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diff --git a/deps/jemalloc/doc/jemalloc.xml.in b/deps/jemalloc/doc/jemalloc.xml.in deleted file mode 100644 index 1e12fd3a8..000000000 --- a/deps/jemalloc/doc/jemalloc.xml.in +++ /dev/null @@ -1,3379 +0,0 @@ -<?xml version='1.0' encoding='UTF-8'?> -<?xml-stylesheet type="text/xsl" - href="http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl"?> -<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" - "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [ -]> - -<refentry> - <refentryinfo> - <title>User Manual</title> - <productname>jemalloc</productname> - <releaseinfo role="version">@jemalloc_version@</releaseinfo> - <authorgroup> - <author> - <firstname>Jason</firstname> - <surname>Evans</surname> - <personblurb>Author</personblurb> - </author> - </authorgroup> - </refentryinfo> - <refmeta> - <refentrytitle>JEMALLOC</refentrytitle> - <manvolnum>3</manvolnum> - </refmeta> - <refnamediv> - <refdescriptor>jemalloc</refdescriptor> - <refname>jemalloc</refname> - <!-- Each refname causes a man page file to be created. Only if this were - the system malloc(3) implementation would these files be appropriate. - <refname>malloc</refname> - <refname>calloc</refname> - <refname>posix_memalign</refname> - <refname>aligned_alloc</refname> - <refname>realloc</refname> - <refname>free</refname> - <refname>mallocx</refname> - <refname>rallocx</refname> - <refname>xallocx</refname> - <refname>sallocx</refname> - <refname>dallocx</refname> - <refname>sdallocx</refname> - <refname>nallocx</refname> - <refname>mallctl</refname> - <refname>mallctlnametomib</refname> - <refname>mallctlbymib</refname> - <refname>malloc_stats_print</refname> - <refname>malloc_usable_size</refname> - --> - <refpurpose>general purpose memory allocation functions</refpurpose> - </refnamediv> - <refsect1 id="library"> - <title>LIBRARY</title> - <para>This manual describes jemalloc @jemalloc_version@. More information - can be found at the <ulink - url="http://jemalloc.net/">jemalloc website</ulink>.</para> - </refsect1> - <refsynopsisdiv> - <title>SYNOPSIS</title> - <funcsynopsis> - <funcsynopsisinfo>#include <<filename class="headerfile">jemalloc/jemalloc.h</filename>></funcsynopsisinfo> - <refsect2> - <title>Standard API</title> - <funcprototype> - <funcdef>void *<function>malloc</function></funcdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void *<function>calloc</function></funcdef> - <paramdef>size_t <parameter>number</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>int <function>posix_memalign</function></funcdef> - <paramdef>void **<parameter>ptr</parameter></paramdef> - <paramdef>size_t <parameter>alignment</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void *<function>aligned_alloc</function></funcdef> - <paramdef>size_t <parameter>alignment</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void *<function>realloc</function></funcdef> - <paramdef>void *<parameter>ptr</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void <function>free</function></funcdef> - <paramdef>void *<parameter>ptr</parameter></paramdef> - </funcprototype> - </refsect2> - <refsect2> - <title>Non-standard API</title> - <funcprototype> - <funcdef>void *<function>mallocx</function></funcdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>int <parameter>flags</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void *<function>rallocx</function></funcdef> - <paramdef>void *<parameter>ptr</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>int <parameter>flags</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>size_t <function>xallocx</function></funcdef> - <paramdef>void *<parameter>ptr</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>size_t <parameter>extra</parameter></paramdef> - <paramdef>int <parameter>flags</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>size_t <function>sallocx</function></funcdef> - <paramdef>void *<parameter>ptr</parameter></paramdef> - <paramdef>int <parameter>flags</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void <function>dallocx</function></funcdef> - <paramdef>void *<parameter>ptr</parameter></paramdef> - <paramdef>int <parameter>flags</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void <function>sdallocx</function></funcdef> - <paramdef>void *<parameter>ptr</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>int <parameter>flags</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>size_t <function>nallocx</function></funcdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>int <parameter>flags</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>int <function>mallctl</function></funcdef> - <paramdef>const char *<parameter>name</parameter></paramdef> - <paramdef>void *<parameter>oldp</parameter></paramdef> - <paramdef>size_t *<parameter>oldlenp</parameter></paramdef> - <paramdef>void *<parameter>newp</parameter></paramdef> - <paramdef>size_t <parameter>newlen</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>int <function>mallctlnametomib</function></funcdef> - <paramdef>const char *<parameter>name</parameter></paramdef> - <paramdef>size_t *<parameter>mibp</parameter></paramdef> - <paramdef>size_t *<parameter>miblenp</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>int <function>mallctlbymib</function></funcdef> - <paramdef>const size_t *<parameter>mib</parameter></paramdef> - <paramdef>size_t <parameter>miblen</parameter></paramdef> - <paramdef>void *<parameter>oldp</parameter></paramdef> - <paramdef>size_t *<parameter>oldlenp</parameter></paramdef> - <paramdef>void *<parameter>newp</parameter></paramdef> - <paramdef>size_t <parameter>newlen</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void <function>malloc_stats_print</function></funcdef> - <paramdef>void <parameter>(*write_cb)</parameter> - <funcparams>void *, const char *</funcparams> - </paramdef> - <paramdef>void *<parameter>cbopaque</parameter></paramdef> - <paramdef>const char *<parameter>opts</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>size_t <function>malloc_usable_size</function></funcdef> - <paramdef>const void *<parameter>ptr</parameter></paramdef> - </funcprototype> - <funcprototype> - <funcdef>void <function>(*malloc_message)</function></funcdef> - <paramdef>void *<parameter>cbopaque</parameter></paramdef> - <paramdef>const char *<parameter>s</parameter></paramdef> - </funcprototype> - <para><type>const char *</type><varname>malloc_conf</varname>;</para> - </refsect2> - </funcsynopsis> - </refsynopsisdiv> - <refsect1 id="description"> - <title>DESCRIPTION</title> - <refsect2> - <title>Standard API</title> - - <para>The <function>malloc()</function> function allocates - <parameter>size</parameter> bytes of uninitialized memory. The allocated - space is suitably aligned (after possible pointer coercion) for storage - of any type of object.</para> - - <para>The <function>calloc()</function> function allocates - space for <parameter>number</parameter> objects, each - <parameter>size</parameter> bytes in length. The result is identical to - calling <function>malloc()</function> with an argument of - <parameter>number</parameter> * <parameter>size</parameter>, with the - exception that the allocated memory is explicitly initialized to zero - bytes.</para> - - <para>The <function>posix_memalign()</function> function - allocates <parameter>size</parameter> bytes of memory such that the - allocation's base address is a multiple of - <parameter>alignment</parameter>, and returns the allocation in the value - pointed to by <parameter>ptr</parameter>. The requested - <parameter>alignment</parameter> must be a power of 2 at least as large as - <code language="C">sizeof(<type>void *</type>)</code>.</para> - - <para>The <function>aligned_alloc()</function> function - allocates <parameter>size</parameter> bytes of memory such that the - allocation's base address is a multiple of - <parameter>alignment</parameter>. The requested - <parameter>alignment</parameter> must be a power of 2. Behavior is - undefined if <parameter>size</parameter> is not an integral multiple of - <parameter>alignment</parameter>.</para> - - <para>The <function>realloc()</function> function changes the - size of the previously allocated memory referenced by - <parameter>ptr</parameter> to <parameter>size</parameter> bytes. The - contents of the memory are unchanged up to the lesser of the new and old - sizes. If the new size is larger, the contents of the newly allocated - portion of the memory are undefined. Upon success, the memory referenced - by <parameter>ptr</parameter> is freed and a pointer to the newly - allocated memory is returned. Note that - <function>realloc()</function> may move the memory allocation, - resulting in a different return value than <parameter>ptr</parameter>. - If <parameter>ptr</parameter> is <constant>NULL</constant>, the - <function>realloc()</function> function behaves identically to - <function>malloc()</function> for the specified size.</para> - - <para>The <function>free()</function> function causes the - allocated memory referenced by <parameter>ptr</parameter> to be made - available for future allocations. If <parameter>ptr</parameter> is - <constant>NULL</constant>, no action occurs.</para> - </refsect2> - <refsect2> - <title>Non-standard API</title> - <para>The <function>mallocx()</function>, - <function>rallocx()</function>, - <function>xallocx()</function>, - <function>sallocx()</function>, - <function>dallocx()</function>, - <function>sdallocx()</function>, and - <function>nallocx()</function> functions all have a - <parameter>flags</parameter> argument that can be used to specify - options. The functions only check the options that are contextually - relevant. Use bitwise or (<code language="C">|</code>) operations to - specify one or more of the following: - <variablelist> - <varlistentry id="MALLOCX_LG_ALIGN"> - <term><constant>MALLOCX_LG_ALIGN(<parameter>la</parameter>) - </constant></term> - - <listitem><para>Align the memory allocation to start at an address - that is a multiple of <code language="C">(1 << - <parameter>la</parameter>)</code>. This macro does not validate - that <parameter>la</parameter> is within the valid - range.</para></listitem> - </varlistentry> - <varlistentry id="MALLOCX_ALIGN"> - <term><constant>MALLOCX_ALIGN(<parameter>a</parameter>) - </constant></term> - - <listitem><para>Align the memory allocation to start at an address - that is a multiple of <parameter>a</parameter>, where - <parameter>a</parameter> is a power of two. This macro does not - validate that <parameter>a</parameter> is a power of 2. - </para></listitem> - </varlistentry> - <varlistentry id="MALLOCX_ZERO"> - <term><constant>MALLOCX_ZERO</constant></term> - - <listitem><para>Initialize newly allocated memory to contain zero - bytes. In the growing reallocation case, the real size prior to - reallocation defines the boundary between untouched bytes and those - that are initialized to contain zero bytes. If this macro is - absent, newly allocated memory is uninitialized.</para></listitem> - </varlistentry> - <varlistentry id="MALLOCX_TCACHE"> - <term><constant>MALLOCX_TCACHE(<parameter>tc</parameter>) - </constant></term> - - <listitem><para>Use the thread-specific cache (tcache) specified by - the identifier <parameter>tc</parameter>, which must have been - acquired via the <link - linkend="tcache.create"><mallctl>tcache.create</mallctl></link> - mallctl. This macro does not validate that - <parameter>tc</parameter> specifies a valid - identifier.</para></listitem> - </varlistentry> - <varlistentry id="MALLOC_TCACHE_NONE"> - <term><constant>MALLOCX_TCACHE_NONE</constant></term> - - <listitem><para>Do not use a thread-specific cache (tcache). Unless - <constant>MALLOCX_TCACHE(<parameter>tc</parameter>)</constant> or - <constant>MALLOCX_TCACHE_NONE</constant> is specified, an - automatically managed tcache will be used under many circumstances. - This macro cannot be used in the same <parameter>flags</parameter> - argument as - <constant>MALLOCX_TCACHE(<parameter>tc</parameter>)</constant>.</para></listitem> - </varlistentry> - <varlistentry id="MALLOCX_ARENA"> - <term><constant>MALLOCX_ARENA(<parameter>a</parameter>) - </constant></term> - - <listitem><para>Use the arena specified by the index - <parameter>a</parameter>. This macro has no effect for regions that - were allocated via an arena other than the one specified. This - macro does not validate that <parameter>a</parameter> specifies an - arena index in the valid range.</para></listitem> - </varlistentry> - </variablelist> - </para> - - <para>The <function>mallocx()</function> function allocates at - least <parameter>size</parameter> bytes of memory, and returns a pointer - to the base address of the allocation. Behavior is undefined if - <parameter>size</parameter> is <constant>0</constant>.</para> - - <para>The <function>rallocx()</function> function resizes the - allocation at <parameter>ptr</parameter> to be at least - <parameter>size</parameter> bytes, and returns a pointer to the base - address of the resulting allocation, which may or may not have moved from - its original location. Behavior is undefined if - <parameter>size</parameter> is <constant>0</constant>.</para> - - <para>The <function>xallocx()</function> function resizes the - allocation at <parameter>ptr</parameter> in place to be at least - <parameter>size</parameter> bytes, and returns the real size of the - allocation. If <parameter>extra</parameter> is non-zero, an attempt is - made to resize the allocation to be at least <code - language="C">(<parameter>size</parameter> + - <parameter>extra</parameter>)</code> bytes, though inability to allocate - the extra byte(s) will not by itself result in failure to resize. - Behavior is undefined if <parameter>size</parameter> is - <constant>0</constant>, or if <code - language="C">(<parameter>size</parameter> + <parameter>extra</parameter> - > <constant>SIZE_T_MAX</constant>)</code>.</para> - - <para>The <function>sallocx()</function> function returns the - real size of the allocation at <parameter>ptr</parameter>.</para> - - <para>The <function>dallocx()</function> function causes the - memory referenced by <parameter>ptr</parameter> to be made available for - future allocations.</para> - - <para>The <function>sdallocx()</function> function is an - extension of <function>dallocx()</function> with a - <parameter>size</parameter> parameter to allow the caller to pass in the - allocation size as an optimization. The minimum valid input size is the - original requested size of the allocation, and the maximum valid input - size is the corresponding value returned by - <function>nallocx()</function> or - <function>sallocx()</function>.</para> - - <para>The <function>nallocx()</function> function allocates no - memory, but it performs the same size computation as the - <function>mallocx()</function> function, and returns the real - size of the allocation that would result from the equivalent - <function>mallocx()</function> function call, or - <constant>0</constant> if the inputs exceed the maximum supported size - class and/or alignment. Behavior is undefined if - <parameter>size</parameter> is <constant>0</constant>.</para> - - <para>The <function>mallctl()</function> function provides a - general interface for introspecting the memory allocator, as well as - setting modifiable parameters and triggering actions. The - period-separated <parameter>name</parameter> argument specifies a - location in a tree-structured namespace; see the <xref - linkend="mallctl_namespace" xrefstyle="template:%t"/> section for - documentation on the tree contents. To read a value, pass a pointer via - <parameter>oldp</parameter> to adequate space to contain the value, and a - pointer to its length via <parameter>oldlenp</parameter>; otherwise pass - <constant>NULL</constant> and <constant>NULL</constant>. Similarly, to - write a value, pass a pointer to the value via - <parameter>newp</parameter>, and its length via - <parameter>newlen</parameter>; otherwise pass <constant>NULL</constant> - and <constant>0</constant>.</para> - - <para>The <function>mallctlnametomib()</function> function - provides a way to avoid repeated name lookups for applications that - repeatedly query the same portion of the namespace, by translating a name - to a <quote>Management Information Base</quote> (MIB) that can be passed - repeatedly to <function>mallctlbymib()</function>. Upon - successful return from <function>mallctlnametomib()</function>, - <parameter>mibp</parameter> contains an array of - <parameter>*miblenp</parameter> integers, where - <parameter>*miblenp</parameter> is the lesser of the number of components - in <parameter>name</parameter> and the input value of - <parameter>*miblenp</parameter>. Thus it is possible to pass a - <parameter>*miblenp</parameter> that is smaller than the number of - period-separated name components, which results in a partial MIB that can - be used as the basis for constructing a complete MIB. For name - components that are integers (e.g. the 2 in - <link - linkend="arenas.bin.i.size"><mallctl>arenas.bin.2.size</mallctl></link>), - the corresponding MIB component will always be that integer. Therefore, - it is legitimate to construct code like the following: <programlisting - language="C"><![CDATA[ -unsigned nbins, i; -size_t mib[4]; -size_t len, miblen; - -len = sizeof(nbins); -mallctl("arenas.nbins", &nbins, &len, NULL, 0); - -miblen = 4; -mallctlnametomib("arenas.bin.0.size", mib, &miblen); -for (i = 0; i < nbins; i++) { - size_t bin_size; - - mib[2] = i; - len = sizeof(bin_size); - mallctlbymib(mib, miblen, (void *)&bin_size, &len, NULL, 0); - /* Do something with bin_size... */ -}]]></programlisting></para> - - <varlistentry id="malloc_stats_print_opts"> - </varlistentry> - <para>The <function>malloc_stats_print()</function> function writes - summary statistics via the <parameter>write_cb</parameter> callback - function pointer and <parameter>cbopaque</parameter> data passed to - <parameter>write_cb</parameter>, or <function>malloc_message()</function> - if <parameter>write_cb</parameter> is <constant>NULL</constant>. The - statistics are presented in human-readable form unless <quote>J</quote> is - specified as a character within the <parameter>opts</parameter> string, in - which case the statistics are presented in <ulink - url="http://www.json.org/">JSON format</ulink>. This function can be - called repeatedly. General information that never changes during - execution can be omitted by specifying <quote>g</quote> as a character - within the <parameter>opts</parameter> string. Note that - <function>malloc_message()</function> uses the - <function>mallctl*()</function> functions internally, so inconsistent - statistics can be reported if multiple threads use these functions - simultaneously. If <option>--enable-stats</option> is specified during - configuration, <quote>m</quote>, <quote>d</quote>, and <quote>a</quote> - can be specified to omit merged arena, destroyed merged arena, and per - arena statistics, respectively; <quote>b</quote> and <quote>l</quote> can - be specified to omit per size class statistics for bins and large objects, - respectively; <quote>x</quote> can be specified to omit all mutex - statistics. Unrecognized characters are silently ignored. Note that - thread caching may prevent some statistics from being completely up to - date, since extra locking would be required to merge counters that track - thread cache operations.</para> - - <para>The <function>malloc_usable_size()</function> function - returns the usable size of the allocation pointed to by - <parameter>ptr</parameter>. The return value may be larger than the size - that was requested during allocation. The - <function>malloc_usable_size()</function> function is not a - mechanism for in-place <function>realloc()</function>; rather - it is provided solely as a tool for introspection purposes. Any - discrepancy between the requested allocation size and the size reported - by <function>malloc_usable_size()</function> should not be - depended on, since such behavior is entirely implementation-dependent. - </para> - </refsect2> - </refsect1> - <refsect1 id="tuning"> - <title>TUNING</title> - <para>Once, when the first call is made to one of the memory allocation - routines, the allocator initializes its internals based in part on various - options that can be specified at compile- or run-time.</para> - - <para>The string specified via <option>--with-malloc-conf</option>, the - string pointed to by the global variable <varname>malloc_conf</varname>, the - <quote>name</quote> of the file referenced by the symbolic link named - <filename class="symlink">/etc/malloc.conf</filename>, and the value of the - environment variable <envar>MALLOC_CONF</envar>, will be interpreted, in - that order, from left to right as options. Note that - <varname>malloc_conf</varname> may be read before - <function>main()</function> is entered, so the declaration of - <varname>malloc_conf</varname> should specify an initializer that contains - the final value to be read by jemalloc. <option>--with-malloc-conf</option> - and <varname>malloc_conf</varname> are compile-time mechanisms, whereas - <filename class="symlink">/etc/malloc.conf</filename> and - <envar>MALLOC_CONF</envar> can be safely set any time prior to program - invocation.</para> - - <para>An options string is a comma-separated list of option:value pairs. - There is one key corresponding to each <link - linkend="opt.abort"><mallctl>opt.*</mallctl></link> mallctl (see the <xref - linkend="mallctl_namespace" xrefstyle="template:%t"/> section for options - documentation). For example, <literal>abort:true,narenas:1</literal> sets - the <link linkend="opt.abort"><mallctl>opt.abort</mallctl></link> and <link - linkend="opt.narenas"><mallctl>opt.narenas</mallctl></link> options. Some - options have boolean values (true/false), others have integer values (base - 8, 10, or 16, depending on prefix), and yet others have raw string - values.</para> - </refsect1> - <refsect1 id="implementation_notes"> - <title>IMPLEMENTATION NOTES</title> - <para>Traditionally, allocators have used - <citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> to obtain memory, which is - suboptimal for several reasons, including race conditions, increased - fragmentation, and artificial limitations on maximum usable memory. If - <citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> is supported by the operating - system, this allocator uses both - <citerefentry><refentrytitle>mmap</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> and - <citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry>, in that order of preference; - otherwise only <citerefentry><refentrytitle>mmap</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> is used.</para> - - <para>This allocator uses multiple arenas in order to reduce lock - contention for threaded programs on multi-processor systems. This works - well with regard to threading scalability, but incurs some costs. There is - a small fixed per-arena overhead, and additionally, arenas manage memory - completely independently of each other, which means a small fixed increase - in overall memory fragmentation. These overheads are not generally an - issue, given the number of arenas normally used. Note that using - substantially more arenas than the default is not likely to improve - performance, mainly due to reduced cache performance. However, it may make - sense to reduce the number of arenas if an application does not make much - use of the allocation functions.</para> - - <para>In addition to multiple arenas, this allocator supports - thread-specific caching, in order to make it possible to completely avoid - synchronization for most allocation requests. Such caching allows very fast - allocation in the common case, but it increases memory usage and - fragmentation, since a bounded number of objects can remain allocated in - each thread cache.</para> - - <para>Memory is conceptually broken into extents. Extents are always - aligned to multiples of the page size. This alignment makes it possible to - find metadata for user objects quickly. User objects are broken into two - categories according to size: small and large. Contiguous small objects - comprise a slab, which resides within a single extent, whereas large objects - each have their own extents backing them.</para> - - <para>Small objects are managed in groups by slabs. Each slab maintains - a bitmap to track which regions are in use. Allocation requests that are no - more than half the quantum (8 or 16, depending on architecture) are rounded - up to the nearest power of two that is at least <code - language="C">sizeof(<type>double</type>)</code>. All other object size - classes are multiples of the quantum, spaced such that there are four size - classes for each doubling in size, which limits internal fragmentation to - approximately 20% for all but the smallest size classes. Small size classes - are smaller than four times the page size, and large size classes extend - from four times the page size up to the largest size class that does not - exceed <constant>PTRDIFF_MAX</constant>.</para> - - <para>Allocations are packed tightly together, which can be an issue for - multi-threaded applications. If you need to assure that allocations do not - suffer from cacheline sharing, round your allocation requests up to the - nearest multiple of the cacheline size, or specify cacheline alignment when - allocating.</para> - - <para>The <function>realloc()</function>, - <function>rallocx()</function>, and - <function>xallocx()</function> functions may resize allocations - without moving them under limited circumstances. Unlike the - <function>*allocx()</function> API, the standard API does not - officially round up the usable size of an allocation to the nearest size - class, so technically it is necessary to call - <function>realloc()</function> to grow e.g. a 9-byte allocation to - 16 bytes, or shrink a 16-byte allocation to 9 bytes. Growth and shrinkage - trivially succeeds in place as long as the pre-size and post-size both round - up to the same size class. No other API guarantees are made regarding - in-place resizing, but the current implementation also tries to resize large - allocations in place, as long as the pre-size and post-size are both large. - For shrinkage to succeed, the extent allocator must support splitting (see - <link - linkend="arena.i.extent_hooks"><mallctl>arena.<i>.extent_hooks</mallctl></link>). - Growth only succeeds if the trailing memory is currently available, and the - extent allocator supports merging.</para> - - <para>Assuming 4 KiB pages and a 16-byte quantum on a 64-bit system, the - size classes in each category are as shown in <xref linkend="size_classes" - xrefstyle="template:Table %n"/>.</para> - - <table xml:id="size_classes" frame="all"> - <title>Size classes</title> - <tgroup cols="3" colsep="1" rowsep="1"> - <colspec colname="c1" align="left"/> - <colspec colname="c2" align="right"/> - <colspec colname="c3" align="left"/> - <thead> - <row> - <entry>Category</entry> - <entry>Spacing</entry> - <entry>Size</entry> - </row> - </thead> - <tbody> - <row> - <entry morerows="8">Small</entry> - <entry>lg</entry> - <entry>[8]</entry> - </row> - <row> - <entry>16</entry> - <entry>[16, 32, 48, 64, 80, 96, 112, 128]</entry> - </row> - <row> - <entry>32</entry> - <entry>[160, 192, 224, 256]</entry> - </row> - <row> - <entry>64</entry> - <entry>[320, 384, 448, 512]</entry> - </row> - <row> - <entry>128</entry> - <entry>[640, 768, 896, 1024]</entry> - </row> - <row> - <entry>256</entry> - <entry>[1280, 1536, 1792, 2048]</entry> - </row> - <row> - <entry>512</entry> - <entry>[2560, 3072, 3584, 4096]</entry> - </row> - <row> - <entry>1 KiB</entry> - <entry>[5 KiB, 6 KiB, 7 KiB, 8 KiB]</entry> - </row> - <row> - <entry>2 KiB</entry> - <entry>[10 KiB, 12 KiB, 14 KiB]</entry> - </row> - <row> - <entry morerows="15">Large</entry> - <entry>2 KiB</entry> - <entry>[16 KiB]</entry> - </row> - <row> - <entry>4 KiB</entry> - <entry>[20 KiB, 24 KiB, 28 KiB, 32 KiB]</entry> - </row> - <row> - <entry>8 KiB</entry> - <entry>[40 KiB, 48 KiB, 54 KiB, 64 KiB]</entry> - </row> - <row> - <entry>16 KiB</entry> - <entry>[80 KiB, 96 KiB, 112 KiB, 128 KiB]</entry> - </row> - <row> - <entry>32 KiB</entry> - <entry>[160 KiB, 192 KiB, 224 KiB, 256 KiB]</entry> - </row> - <row> - <entry>64 KiB</entry> - <entry>[320 KiB, 384 KiB, 448 KiB, 512 KiB]</entry> - </row> - <row> - <entry>128 KiB</entry> - <entry>[640 KiB, 768 KiB, 896 KiB, 1 MiB]</entry> - </row> - <row> - <entry>256 KiB</entry> - <entry>[1280 KiB, 1536 KiB, 1792 KiB, 2 MiB]</entry> - </row> - <row> - <entry>512 KiB</entry> - <entry>[2560 KiB, 3 MiB, 3584 KiB, 4 MiB]</entry> - </row> - <row> - <entry>1 MiB</entry> - <entry>[5 MiB, 6 MiB, 7 MiB, 8 MiB]</entry> - </row> - <row> - <entry>2 MiB</entry> - <entry>[10 MiB, 12 MiB, 14 MiB, 16 MiB]</entry> - </row> - <row> - <entry>4 MiB</entry> - <entry>[20 MiB, 24 MiB, 28 MiB, 32 MiB]</entry> - </row> - <row> - <entry>8 MiB</entry> - <entry>[40 MiB, 48 MiB, 56 MiB, 64 MiB]</entry> - </row> - <row> - <entry>...</entry> - <entry>...</entry> - </row> - <row> - <entry>512 PiB</entry> - <entry>[2560 PiB, 3 EiB, 3584 PiB, 4 EiB]</entry> - </row> - <row> - <entry>1 EiB</entry> - <entry>[5 EiB, 6 EiB, 7 EiB]</entry> - </row> - </tbody> - </tgroup> - </table> - </refsect1> - <refsect1 id="mallctl_namespace"> - <title>MALLCTL NAMESPACE</title> - <para>The following names are defined in the namespace accessible via the - <function>mallctl*()</function> functions. Value types are specified in - parentheses, their readable/writable statuses are encoded as - <literal>rw</literal>, <literal>r-</literal>, <literal>-w</literal>, or - <literal>--</literal>, and required build configuration flags follow, if - any. A name element encoded as <literal><i></literal> or - <literal><j></literal> indicates an integer component, where the - integer varies from 0 to some upper value that must be determined via - introspection. In the case of <mallctl>stats.arenas.<i>.*</mallctl> - and <mallctl>arena.<i>.{initialized,purge,decay,dss}</mallctl>, - <literal><i></literal> equal to - <constant>MALLCTL_ARENAS_ALL</constant> can be used to operate on all arenas - or access the summation of statistics from all arenas; similarly - <literal><i></literal> equal to - <constant>MALLCTL_ARENAS_DESTROYED</constant> can be used to access the - summation of statistics from all destroyed arenas. These constants can be - utilized either via <function>mallctlnametomib()</function> followed by - <function>mallctlbymib()</function>, or via code such as the following: - <programlisting language="C"><![CDATA[ -#define STRINGIFY_HELPER(x) #x -#define STRINGIFY(x) STRINGIFY_HELPER(x) - -mallctl("arena." STRINGIFY(MALLCTL_ARENAS_ALL) ".decay", - NULL, NULL, NULL, 0);]]></programlisting> - Take special note of the <link - linkend="epoch"><mallctl>epoch</mallctl></link> mallctl, which controls - refreshing of cached dynamic statistics.</para> - - <variablelist> - <varlistentry id="version"> - <term> - <mallctl>version</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - </term> - <listitem><para>Return the jemalloc version string.</para></listitem> - </varlistentry> - - <varlistentry id="epoch"> - <term> - <mallctl>epoch</mallctl> - (<type>uint64_t</type>) - <literal>rw</literal> - </term> - <listitem><para>If a value is passed in, refresh the data from which - the <function>mallctl*()</function> functions report values, - and increment the epoch. Return the current epoch. This is useful for - detecting whether another thread caused a refresh.</para></listitem> - </varlistentry> - - <varlistentry id="background_thread"> - <term> - <mallctl>background_thread</mallctl> - (<type>bool</type>) - <literal>rw</literal> - </term> - <listitem><para>Enable/disable internal background worker threads. When - set to true, background threads are created on demand (the number of - background threads will be no more than the number of CPUs or active - arenas). Threads run periodically, and handle <link - linkend="arena.i.decay">purging</link> asynchronously. When switching - off, background threads are terminated synchronously. Note that after - <citerefentry><refentrytitle>fork</refentrytitle><manvolnum>2</manvolnum></citerefentry> - function, the state in the child process will be disabled regardless - the state in parent process. See <link - linkend="stats.background_thread.num_threads"><mallctl>stats.background_thread</mallctl></link> - for related stats. <link - linkend="opt.background_thread"><mallctl>opt.background_thread</mallctl></link> - can be used to set the default option. This option is only available on - selected pthread-based platforms.</para></listitem> - </varlistentry> - - <varlistentry id="max_background_threads"> - <term> - <mallctl>max_background_threads</mallctl> - (<type>size_t</type>) - <literal>rw</literal> - </term> - <listitem><para>Maximum number of background worker threads that will - be created. This value is capped at <link - linkend="opt.max_background_threads"><mallctl>opt.max_background_threads</mallctl></link> at - startup.</para></listitem> - </varlistentry> - - <varlistentry id="config.cache_oblivious"> - <term> - <mallctl>config.cache_oblivious</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-cache-oblivious</option> was specified - during build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.debug"> - <term> - <mallctl>config.debug</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-debug</option> was specified during - build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.fill"> - <term> - <mallctl>config.fill</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-fill</option> was specified during - build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.lazy_lock"> - <term> - <mallctl>config.lazy_lock</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-lazy-lock</option> was specified - during build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.malloc_conf"> - <term> - <mallctl>config.malloc_conf</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - </term> - <listitem><para>Embedded configure-time-specified run-time options - string, empty unless <option>--with-malloc-conf</option> was specified - during build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.prof"> - <term> - <mallctl>config.prof</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-prof</option> was specified during - build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.prof_libgcc"> - <term> - <mallctl>config.prof_libgcc</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--disable-prof-libgcc</option> was not - specified during build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.prof_libunwind"> - <term> - <mallctl>config.prof_libunwind</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-prof-libunwind</option> was specified - during build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.stats"> - <term> - <mallctl>config.stats</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-stats</option> was specified during - build configuration.</para></listitem> - </varlistentry> - - - <varlistentry id="config.utrace"> - <term> - <mallctl>config.utrace</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-utrace</option> was specified during - build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="config.xmalloc"> - <term> - <mallctl>config.xmalloc</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para><option>--enable-xmalloc</option> was specified during - build configuration.</para></listitem> - </varlistentry> - - <varlistentry id="opt.abort"> - <term> - <mallctl>opt.abort</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para>Abort-on-warning enabled/disabled. If true, most - warnings are fatal. Note that runtime option warnings are not included - (see <link - linkend="opt.abort_conf"><mallctl>opt.abort_conf</mallctl></link> for - that). The process will call - <citerefentry><refentrytitle>abort</refentrytitle> - <manvolnum>3</manvolnum></citerefentry> in these cases. This option is - disabled by default unless <option>--enable-debug</option> is - specified during configuration, in which case it is enabled by default. - </para></listitem> - </varlistentry> - - <varlistentry id="opt.abort_conf"> - <term> - <mallctl>opt.abort_conf</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para>Abort-on-invalid-configuration enabled/disabled. If - true, invalid runtime options are fatal. The process will call - <citerefentry><refentrytitle>abort</refentrytitle> - <manvolnum>3</manvolnum></citerefentry> in these cases. This option is - disabled by default unless <option>--enable-debug</option> is - specified during configuration, in which case it is enabled by default. - </para></listitem> - </varlistentry> - - <varlistentry id="opt.metadata_thp"> - <term> - <mallctl>opt.metadata_thp</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - </term> - <listitem><para>Controls whether to allow jemalloc to use transparent - huge page (THP) for internal metadata (see <link - linkend="stats.metadata">stats.metadata</link>). <quote>always</quote> - allows such usage. <quote>auto</quote> uses no THP initially, but may - begin to do so when metadata usage reaches certain level. The default - is <quote>disabled</quote>.</para></listitem> - </varlistentry> - - <varlistentry id="opt.retain"> - <term> - <mallctl>opt.retain</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para>If true, retain unused virtual memory for later reuse - rather than discarding it by calling - <citerefentry><refentrytitle>munmap</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> or equivalent (see <link - linkend="stats.retained">stats.retained</link> for related details). - This option is disabled by default unless discarding virtual memory is - known to trigger - platform-specific performance problems, e.g. for [64-bit] Linux, which - has a quirk in its virtual memory allocation algorithm that causes - semi-permanent VM map holes under normal jemalloc operation. Although - <citerefentry><refentrytitle>munmap</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> causes issues on 32-bit Linux as - well, retaining virtual memory for 32-bit Linux is disabled by default - due to the practical possibility of address space exhaustion. - </para></listitem> - </varlistentry> - - <varlistentry id="opt.dss"> - <term> - <mallctl>opt.dss</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - </term> - <listitem><para>dss (<citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry>) allocation precedence as - related to <citerefentry><refentrytitle>mmap</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> allocation. The following - settings are supported if - <citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> is supported by the operating - system: <quote>disabled</quote>, <quote>primary</quote>, and - <quote>secondary</quote>; otherwise only <quote>disabled</quote> is - supported. The default is <quote>secondary</quote> if - <citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> is supported by the operating - system; <quote>disabled</quote> otherwise. - </para></listitem> - </varlistentry> - - <varlistentry id="opt.narenas"> - <term> - <mallctl>opt.narenas</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - </term> - <listitem><para>Maximum number of arenas to use for automatic - multiplexing of threads and arenas. The default is four times the - number of CPUs, or one if there is a single CPU.</para></listitem> - </varlistentry> - - <varlistentry id="opt.percpu_arena"> - <term> - <mallctl>opt.percpu_arena</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - </term> - <listitem><para>Per CPU arena mode. Use the <quote>percpu</quote> - setting to enable this feature, which uses number of CPUs to determine - number of arenas, and bind threads to arenas dynamically based on the - CPU the thread runs on currently. <quote>phycpu</quote> setting uses - one arena per physical CPU, which means the two hyper threads on the - same CPU share one arena. Note that no runtime checking regarding the - availability of hyper threading is done at the moment. When set to - <quote>disabled</quote>, narenas and thread to arena association will - not be impacted by this option. The default is <quote>disabled</quote>. - </para></listitem> - </varlistentry> - - <varlistentry id="opt.background_thread"> - <term> - <mallctl>opt.background_thread</mallctl> - (<type>const bool</type>) - <literal>r-</literal> - </term> - <listitem><para>Internal background worker threads enabled/disabled. - Because of potential circular dependencies, enabling background thread - using this option may cause crash or deadlock during initialization. For - a reliable way to use this feature, see <link - linkend="background_thread">background_thread</link> for dynamic control - options and details. This option is disabled by - default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.max_background_threads"> - <term> - <mallctl>opt.max_background_threads</mallctl> - (<type>const size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Maximum number of background threads that will be created - if <link linkend="background_thread">background_thread</link> is set. - Defaults to number of cpus.</para></listitem> - </varlistentry> - - <varlistentry id="opt.dirty_decay_ms"> - <term> - <mallctl>opt.dirty_decay_ms</mallctl> - (<type>ssize_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Approximate time in milliseconds from the creation of a - set of unused dirty pages until an equivalent set of unused dirty pages - is purged (i.e. converted to muzzy via e.g. - <function>madvise(<parameter>...</parameter><parameter><constant>MADV_FREE</constant></parameter>)</function> - if supported by the operating system, or converted to clean otherwise) - and/or reused. Dirty pages are defined as previously having been - potentially written to by the application, and therefore consuming - physical memory, yet having no current use. The pages are incrementally - purged according to a sigmoidal decay curve that starts and ends with - zero purge rate. A decay time of 0 causes all unused dirty pages to be - purged immediately upon creation. A decay time of -1 disables purging. - The default decay time is 10 seconds. See <link - linkend="arenas.dirty_decay_ms"><mallctl>arenas.dirty_decay_ms</mallctl></link> - and <link - linkend="arena.i.dirty_decay_ms"><mallctl>arena.<i>.dirty_decay_ms</mallctl></link> - for related dynamic control options. See <link - linkend="opt.muzzy_decay_ms"><mallctl>opt.muzzy_decay_ms</mallctl></link> - for a description of muzzy pages.</para></listitem> - </varlistentry> - - <varlistentry id="opt.muzzy_decay_ms"> - <term> - <mallctl>opt.muzzy_decay_ms</mallctl> - (<type>ssize_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Approximate time in milliseconds from the creation of a - set of unused muzzy pages until an equivalent set of unused muzzy pages - is purged (i.e. converted to clean) and/or reused. Muzzy pages are - defined as previously having been unused dirty pages that were - subsequently purged in a manner that left them subject to the - reclamation whims of the operating system (e.g. - <function>madvise(<parameter>...</parameter><parameter><constant>MADV_FREE</constant></parameter>)</function>), - and therefore in an indeterminate state. The pages are incrementally - purged according to a sigmoidal decay curve that starts and ends with - zero purge rate. A decay time of 0 causes all unused muzzy pages to be - purged immediately upon creation. A decay time of -1 disables purging. - The default decay time is 10 seconds. See <link - linkend="arenas.muzzy_decay_ms"><mallctl>arenas.muzzy_decay_ms</mallctl></link> - and <link - linkend="arena.i.muzzy_decay_ms"><mallctl>arena.<i>.muzzy_decay_ms</mallctl></link> - for related dynamic control options.</para></listitem> - </varlistentry> - - <varlistentry id="opt.lg_extent_max_active_fit"> - <term> - <mallctl>opt.lg_extent_max_active_fit</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>When reusing dirty extents, this determines the (log - base 2 of the) maximum ratio between the size of the active extent - selected (to split off from) and the size of the requested allocation. - This prevents the splitting of large active extents for smaller - allocations, which can reduce fragmentation over the long run - (especially for non-active extents). Lower value may reduce - fragmentation, at the cost of extra active extents. The default value - is 6, which gives a maximum ratio of 64 (2^6).</para></listitem> - </varlistentry> - - <varlistentry id="opt.stats_print"> - <term> - <mallctl>opt.stats_print</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para>Enable/disable statistics printing at exit. If - enabled, the <function>malloc_stats_print()</function> - function is called at program exit via an - <citerefentry><refentrytitle>atexit</refentrytitle> - <manvolnum>3</manvolnum></citerefentry> function. <link - linkend="opt.stats_print_opts"><mallctl>opt.stats_print_opts</mallctl></link> - can be combined to specify output options. If - <option>--enable-stats</option> is specified during configuration, this - has the potential to cause deadlock for a multi-threaded process that - exits while one or more threads are executing in the memory allocation - functions. Furthermore, <function>atexit()</function> may - allocate memory during application initialization and then deadlock - internally when jemalloc in turn calls - <function>atexit()</function>, so this option is not - universally usable (though the application can register its own - <function>atexit()</function> function with equivalent - functionality). Therefore, this option should only be used with care; - it is primarily intended as a performance tuning aid during application - development. This option is disabled by default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.stats_print_opts"> - <term> - <mallctl>opt.stats_print_opts</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - </term> - <listitem><para>Options (the <parameter>opts</parameter> string) to pass - to the <function>malloc_stats_print()</function> at exit (enabled - through <link - linkend="opt.stats_print"><mallctl>opt.stats_print</mallctl></link>). See - available options in <link - linkend="malloc_stats_print_opts"><function>malloc_stats_print()</function></link>. - Has no effect unless <link - linkend="opt.stats_print"><mallctl>opt.stats_print</mallctl></link> is - enabled. The default is <quote></quote>.</para></listitem> - </varlistentry> - - <varlistentry id="opt.junk"> - <term> - <mallctl>opt.junk</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - [<option>--enable-fill</option>] - </term> - <listitem><para>Junk filling. If set to <quote>alloc</quote>, each byte - of uninitialized allocated memory will be initialized to - <literal>0xa5</literal>. If set to <quote>free</quote>, all deallocated - memory will be initialized to <literal>0x5a</literal>. If set to - <quote>true</quote>, both allocated and deallocated memory will be - initialized, and if set to <quote>false</quote>, junk filling be - disabled entirely. This is intended for debugging and will impact - performance negatively. This option is <quote>false</quote> by default - unless <option>--enable-debug</option> is specified during - configuration, in which case it is <quote>true</quote> by - default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.zero"> - <term> - <mallctl>opt.zero</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-fill</option>] - </term> - <listitem><para>Zero filling enabled/disabled. If enabled, each byte - of uninitialized allocated memory will be initialized to 0. Note that - this initialization only happens once for each byte, so - <function>realloc()</function> and - <function>rallocx()</function> calls do not zero memory that - was previously allocated. This is intended for debugging and will - impact performance negatively. This option is disabled by default. - </para></listitem> - </varlistentry> - - <varlistentry id="opt.utrace"> - <term> - <mallctl>opt.utrace</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-utrace</option>] - </term> - <listitem><para>Allocation tracing based on - <citerefentry><refentrytitle>utrace</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> enabled/disabled. This option - is disabled by default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.xmalloc"> - <term> - <mallctl>opt.xmalloc</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-xmalloc</option>] - </term> - <listitem><para>Abort-on-out-of-memory enabled/disabled. If enabled, - rather than returning failure for any allocation function, display a - diagnostic message on <constant>STDERR_FILENO</constant> and cause the - program to drop core (using - <citerefentry><refentrytitle>abort</refentrytitle> - <manvolnum>3</manvolnum></citerefentry>). If an application is - designed to depend on this behavior, set the option at compile time by - including the following in the source code: - <programlisting language="C"><![CDATA[ -malloc_conf = "xmalloc:true";]]></programlisting> - This option is disabled by default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.tcache"> - <term> - <mallctl>opt.tcache</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para>Thread-specific caching (tcache) enabled/disabled. When - there are multiple threads, each thread uses a tcache for objects up to - a certain size. Thread-specific caching allows many allocations to be - satisfied without performing any thread synchronization, at the cost of - increased memory use. See the <link - linkend="opt.lg_tcache_max"><mallctl>opt.lg_tcache_max</mallctl></link> - option for related tuning information. This option is enabled by - default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.lg_tcache_max"> - <term> - <mallctl>opt.lg_tcache_max</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Maximum size class (log base 2) to cache in the - thread-specific cache (tcache). At a minimum, all small size classes - are cached, and at a maximum all large size classes are cached. The - default maximum is 32 KiB (2^15).</para></listitem> - </varlistentry> - - <varlistentry id="opt.thp"> - <term> - <mallctl>opt.thp</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - </term> - <listitem><para>Transparent hugepage (THP) mode. Settings "always", - "never" and "default" are available if THP is supported by the operating - system. The "always" setting enables transparent hugepage for all user - memory mappings with - <parameter><constant>MADV_HUGEPAGE</constant></parameter>; "never" - ensures no transparent hugepage with - <parameter><constant>MADV_NOHUGEPAGE</constant></parameter>; the default - setting "default" makes no changes. Note that: this option does not - affect THP for jemalloc internal metadata (see <link - linkend="opt.metadata_thp"><mallctl>opt.metadata_thp</mallctl></link>); - in addition, for arenas with customized <link - linkend="arena.i.extent_hooks"><mallctl>extent_hooks</mallctl></link>, - this option is bypassed as it is implemented as part of the default - extent hooks.</para></listitem> - </varlistentry> - - <varlistentry id="opt.prof"> - <term> - <mallctl>opt.prof</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Memory profiling enabled/disabled. If enabled, profile - memory allocation activity. See the <link - linkend="opt.prof_active"><mallctl>opt.prof_active</mallctl></link> - option for on-the-fly activation/deactivation. See the <link - linkend="opt.lg_prof_sample"><mallctl>opt.lg_prof_sample</mallctl></link> - option for probabilistic sampling control. See the <link - linkend="opt.prof_accum"><mallctl>opt.prof_accum</mallctl></link> - option for control of cumulative sample reporting. See the <link - linkend="opt.lg_prof_interval"><mallctl>opt.lg_prof_interval</mallctl></link> - option for information on interval-triggered profile dumping, the <link - linkend="opt.prof_gdump"><mallctl>opt.prof_gdump</mallctl></link> - option for information on high-water-triggered profile dumping, and the - <link linkend="opt.prof_final"><mallctl>opt.prof_final</mallctl></link> - option for final profile dumping. Profile output is compatible with - the <command>jeprof</command> command, which is based on the - <command>pprof</command> that is developed as part of the <ulink - url="http://code.google.com/p/gperftools/">gperftools - package</ulink>. See <link linkend="heap_profile_format">HEAP PROFILE - FORMAT</link> for heap profile format documentation.</para></listitem> - </varlistentry> - - <varlistentry id="opt.prof_prefix"> - <term> - <mallctl>opt.prof_prefix</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Filename prefix for profile dumps. If the prefix is - set to the empty string, no automatic dumps will occur; this is - primarily useful for disabling the automatic final heap dump (which - also disables leak reporting, if enabled). The default prefix is - <filename>jeprof</filename>.</para></listitem> - </varlistentry> - - <varlistentry id="opt.prof_active"> - <term> - <mallctl>opt.prof_active</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Profiling activated/deactivated. This is a secondary - control mechanism that makes it possible to start the application with - profiling enabled (see the <link - linkend="opt.prof"><mallctl>opt.prof</mallctl></link> option) but - inactive, then toggle profiling at any time during program execution - with the <link - linkend="prof.active"><mallctl>prof.active</mallctl></link> mallctl. - This option is enabled by default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.prof_thread_active_init"> - <term> - <mallctl>opt.prof_thread_active_init</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Initial setting for <link - linkend="thread.prof.active"><mallctl>thread.prof.active</mallctl></link> - in newly created threads. The initial setting for newly created threads - can also be changed during execution via the <link - linkend="prof.thread_active_init"><mallctl>prof.thread_active_init</mallctl></link> - mallctl. This option is enabled by default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.lg_prof_sample"> - <term> - <mallctl>opt.lg_prof_sample</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Average interval (log base 2) between allocation - samples, as measured in bytes of allocation activity. Increasing the - sampling interval decreases profile fidelity, but also decreases the - computational overhead. The default sample interval is 512 KiB (2^19 - B).</para></listitem> - </varlistentry> - - <varlistentry id="opt.prof_accum"> - <term> - <mallctl>opt.prof_accum</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Reporting of cumulative object/byte counts in profile - dumps enabled/disabled. If this option is enabled, every unique - backtrace must be stored for the duration of execution. Depending on - the application, this can impose a large memory overhead, and the - cumulative counts are not always of interest. This option is disabled - by default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.lg_prof_interval"> - <term> - <mallctl>opt.lg_prof_interval</mallctl> - (<type>ssize_t</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Average interval (log base 2) between memory profile - dumps, as measured in bytes of allocation activity. The actual - interval between dumps may be sporadic because decentralized allocation - counters are used to avoid synchronization bottlenecks. Profiles are - dumped to files named according to the pattern - <filename><prefix>.<pid>.<seq>.i<iseq>.heap</filename>, - where <literal><prefix></literal> is controlled by the - <link - linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> - option. By default, interval-triggered profile dumping is disabled - (encoded as -1). - </para></listitem> - </varlistentry> - - <varlistentry id="opt.prof_gdump"> - <term> - <mallctl>opt.prof_gdump</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Set the initial state of <link - linkend="prof.gdump"><mallctl>prof.gdump</mallctl></link>, which when - enabled triggers a memory profile dump every time the total virtual - memory exceeds the previous maximum. This option is disabled by - default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.prof_final"> - <term> - <mallctl>opt.prof_final</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Use an - <citerefentry><refentrytitle>atexit</refentrytitle> - <manvolnum>3</manvolnum></citerefentry> function to dump final memory - usage to a file named according to the pattern - <filename><prefix>.<pid>.<seq>.f.heap</filename>, - where <literal><prefix></literal> is controlled by the <link - linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> - option. Note that <function>atexit()</function> may allocate - memory during application initialization and then deadlock internally - when jemalloc in turn calls <function>atexit()</function>, so - this option is not universally usable (though the application can - register its own <function>atexit()</function> function with - equivalent functionality). This option is disabled by - default.</para></listitem> - </varlistentry> - - <varlistentry id="opt.prof_leak"> - <term> - <mallctl>opt.prof_leak</mallctl> - (<type>bool</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Leak reporting enabled/disabled. If enabled, use an - <citerefentry><refentrytitle>atexit</refentrytitle> - <manvolnum>3</manvolnum></citerefentry> function to report memory leaks - detected by allocation sampling. See the - <link linkend="opt.prof"><mallctl>opt.prof</mallctl></link> option for - information on analyzing heap profile output. This option is disabled - by default.</para></listitem> - </varlistentry> - - <varlistentry id="thread.arena"> - <term> - <mallctl>thread.arena</mallctl> - (<type>unsigned</type>) - <literal>rw</literal> - </term> - <listitem><para>Get or set the arena associated with the calling - thread. If the specified arena was not initialized beforehand (see the - <link - linkend="arena.i.initialized"><mallctl>arena.i.initialized</mallctl></link> - mallctl), it will be automatically initialized as a side effect of - calling this interface.</para></listitem> - </varlistentry> - - <varlistentry id="thread.allocated"> - <term> - <mallctl>thread.allocated</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Get the total number of bytes ever allocated by the - calling thread. This counter has the potential to wrap around; it is - up to the application to appropriately interpret the counter in such - cases.</para></listitem> - </varlistentry> - - <varlistentry id="thread.allocatedp"> - <term> - <mallctl>thread.allocatedp</mallctl> - (<type>uint64_t *</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Get a pointer to the the value that is returned by the - <link - linkend="thread.allocated"><mallctl>thread.allocated</mallctl></link> - mallctl. This is useful for avoiding the overhead of repeated - <function>mallctl*()</function> calls.</para></listitem> - </varlistentry> - - <varlistentry id="thread.deallocated"> - <term> - <mallctl>thread.deallocated</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Get the total number of bytes ever deallocated by the - calling thread. This counter has the potential to wrap around; it is - up to the application to appropriately interpret the counter in such - cases.</para></listitem> - </varlistentry> - - <varlistentry id="thread.deallocatedp"> - <term> - <mallctl>thread.deallocatedp</mallctl> - (<type>uint64_t *</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Get a pointer to the the value that is returned by the - <link - linkend="thread.deallocated"><mallctl>thread.deallocated</mallctl></link> - mallctl. This is useful for avoiding the overhead of repeated - <function>mallctl*()</function> calls.</para></listitem> - </varlistentry> - - <varlistentry id="thread.tcache.enabled"> - <term> - <mallctl>thread.tcache.enabled</mallctl> - (<type>bool</type>) - <literal>rw</literal> - </term> - <listitem><para>Enable/disable calling thread's tcache. The tcache is - implicitly flushed as a side effect of becoming - disabled (see <link - linkend="thread.tcache.flush"><mallctl>thread.tcache.flush</mallctl></link>). - </para></listitem> - </varlistentry> - - <varlistentry id="thread.tcache.flush"> - <term> - <mallctl>thread.tcache.flush</mallctl> - (<type>void</type>) - <literal>--</literal> - </term> - <listitem><para>Flush calling thread's thread-specific cache (tcache). - This interface releases all cached objects and internal data structures - associated with the calling thread's tcache. Ordinarily, this interface - need not be called, since automatic periodic incremental garbage - collection occurs, and the thread cache is automatically discarded when - a thread exits. However, garbage collection is triggered by allocation - activity, so it is possible for a thread that stops - allocating/deallocating to retain its cache indefinitely, in which case - the developer may find manual flushing useful.</para></listitem> - </varlistentry> - - <varlistentry id="thread.prof.name"> - <term> - <mallctl>thread.prof.name</mallctl> - (<type>const char *</type>) - <literal>r-</literal> or - <literal>-w</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Get/set the descriptive name associated with the calling - thread in memory profile dumps. An internal copy of the name string is - created, so the input string need not be maintained after this interface - completes execution. The output string of this interface should be - copied for non-ephemeral uses, because multiple implementation details - can cause asynchronous string deallocation. Furthermore, each - invocation of this interface can only read or write; simultaneous - read/write is not supported due to string lifetime limitations. The - name string must be nil-terminated and comprised only of characters in - the sets recognized - by <citerefentry><refentrytitle>isgraph</refentrytitle> - <manvolnum>3</manvolnum></citerefentry> and - <citerefentry><refentrytitle>isblank</refentrytitle> - <manvolnum>3</manvolnum></citerefentry>.</para></listitem> - </varlistentry> - - <varlistentry id="thread.prof.active"> - <term> - <mallctl>thread.prof.active</mallctl> - (<type>bool</type>) - <literal>rw</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Control whether sampling is currently active for the - calling thread. This is an activation mechanism in addition to <link - linkend="prof.active"><mallctl>prof.active</mallctl></link>; both must - be active for the calling thread to sample. This flag is enabled by - default.</para></listitem> - </varlistentry> - - <varlistentry id="tcache.create"> - <term> - <mallctl>tcache.create</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - </term> - <listitem><para>Create an explicit thread-specific cache (tcache) and - return an identifier that can be passed to the <link - linkend="MALLOCX_TCACHE"><constant>MALLOCX_TCACHE(<parameter>tc</parameter>)</constant></link> - macro to explicitly use the specified cache rather than the - automatically managed one that is used by default. Each explicit cache - can be used by only one thread at a time; the application must assure - that this constraint holds. - </para></listitem> - </varlistentry> - - <varlistentry id="tcache.flush"> - <term> - <mallctl>tcache.flush</mallctl> - (<type>unsigned</type>) - <literal>-w</literal> - </term> - <listitem><para>Flush the specified thread-specific cache (tcache). The - same considerations apply to this interface as to <link - linkend="thread.tcache.flush"><mallctl>thread.tcache.flush</mallctl></link>, - except that the tcache will never be automatically discarded. - </para></listitem> - </varlistentry> - - <varlistentry id="tcache.destroy"> - <term> - <mallctl>tcache.destroy</mallctl> - (<type>unsigned</type>) - <literal>-w</literal> - </term> - <listitem><para>Flush the specified thread-specific cache (tcache) and - make the identifier available for use during a future tcache creation. - </para></listitem> - </varlistentry> - - <varlistentry id="arena.i.initialized"> - <term> - <mallctl>arena.<i>.initialized</mallctl> - (<type>bool</type>) - <literal>r-</literal> - </term> - <listitem><para>Get whether the specified arena's statistics are - initialized (i.e. the arena was initialized prior to the current epoch). - This interface can also be nominally used to query whether the merged - statistics corresponding to <constant>MALLCTL_ARENAS_ALL</constant> are - initialized (always true).</para></listitem> - </varlistentry> - - <varlistentry id="arena.i.decay"> - <term> - <mallctl>arena.<i>.decay</mallctl> - (<type>void</type>) - <literal>--</literal> - </term> - <listitem><para>Trigger decay-based purging of unused dirty/muzzy pages - for arena <i>, or for all arenas if <i> equals - <constant>MALLCTL_ARENAS_ALL</constant>. The proportion of unused - dirty/muzzy pages to be purged depends on the current time; see <link - linkend="opt.dirty_decay_ms"><mallctl>opt.dirty_decay_ms</mallctl></link> - and <link - linkend="opt.muzzy_decay_ms"><mallctl>opt.muzy_decay_ms</mallctl></link> - for details.</para></listitem> - </varlistentry> - - <varlistentry id="arena.i.purge"> - <term> - <mallctl>arena.<i>.purge</mallctl> - (<type>void</type>) - <literal>--</literal> - </term> - <listitem><para>Purge all unused dirty pages for arena <i>, or for - all arenas if <i> equals <constant>MALLCTL_ARENAS_ALL</constant>. - </para></listitem> - </varlistentry> - - <varlistentry id="arena.i.reset"> - <term> - <mallctl>arena.<i>.reset</mallctl> - (<type>void</type>) - <literal>--</literal> - </term> - <listitem><para>Discard all of the arena's extant allocations. This - interface can only be used with arenas explicitly created via <link - linkend="arenas.create"><mallctl>arenas.create</mallctl></link>. None - of the arena's discarded/cached allocations may accessed afterward. As - part of this requirement, all thread caches which were used to - allocate/deallocate in conjunction with the arena must be flushed - beforehand.</para></listitem> - </varlistentry> - - <varlistentry id="arena.i.destroy"> - <term> - <mallctl>arena.<i>.destroy</mallctl> - (<type>void</type>) - <literal>--</literal> - </term> - <listitem><para>Destroy the arena. Discard all of the arena's extant - allocations using the same mechanism as for <link - linkend="arena.i.reset"><mallctl>arena.<i>.reset</mallctl></link> - (with all the same constraints and side effects), merge the arena stats - into those accessible at arena index - <constant>MALLCTL_ARENAS_DESTROYED</constant>, and then completely - discard all metadata associated with the arena. Future calls to <link - linkend="arenas.create"><mallctl>arenas.create</mallctl></link> may - recycle the arena index. Destruction will fail if any threads are - currently associated with the arena as a result of calls to <link - linkend="thread.arena"><mallctl>thread.arena</mallctl></link>.</para></listitem> - </varlistentry> - - <varlistentry id="arena.i.dss"> - <term> - <mallctl>arena.<i>.dss</mallctl> - (<type>const char *</type>) - <literal>rw</literal> - </term> - <listitem><para>Set the precedence of dss allocation as related to mmap - allocation for arena <i>, or for all arenas if <i> equals - <constant>MALLCTL_ARENAS_ALL</constant>. See <link - linkend="opt.dss"><mallctl>opt.dss</mallctl></link> for supported - settings.</para></listitem> - </varlistentry> - - <varlistentry id="arena.i.dirty_decay_ms"> - <term> - <mallctl>arena.<i>.dirty_decay_ms</mallctl> - (<type>ssize_t</type>) - <literal>rw</literal> - </term> - <listitem><para>Current per-arena approximate time in milliseconds from - the creation of a set of unused dirty pages until an equivalent set of - unused dirty pages is purged and/or reused. Each time this interface is - set, all currently unused dirty pages are considered to have fully - decayed, which causes immediate purging of all unused dirty pages unless - the decay time is set to -1 (i.e. purging disabled). See <link - linkend="opt.dirty_decay_ms"><mallctl>opt.dirty_decay_ms</mallctl></link> - for additional information.</para></listitem> - </varlistentry> - - <varlistentry id="arena.i.muzzy_decay_ms"> - <term> - <mallctl>arena.<i>.muzzy_decay_ms</mallctl> - (<type>ssize_t</type>) - <literal>rw</literal> - </term> - <listitem><para>Current per-arena approximate time in milliseconds from - the creation of a set of unused muzzy pages until an equivalent set of - unused muzzy pages is purged and/or reused. Each time this interface is - set, all currently unused muzzy pages are considered to have fully - decayed, which causes immediate purging of all unused muzzy pages unless - the decay time is set to -1 (i.e. purging disabled). See <link - linkend="opt.muzzy_decay_ms"><mallctl>opt.muzzy_decay_ms</mallctl></link> - for additional information.</para></listitem> - </varlistentry> - - <varlistentry id="arena.i.retain_grow_limit"> - <term> - <mallctl>arena.<i>.retain_grow_limit</mallctl> - (<type>size_t</type>) - <literal>rw</literal> - </term> - <listitem><para>Maximum size to grow retained region (only relevant when - <link linkend="opt.retain"><mallctl>opt.retain</mallctl></link> is - enabled). This controls the maximum increment to expand virtual memory, - or allocation through <link - linkend="arena.i.extent_hooks"><mallctl>arena.<i>extent_hooks</mallctl></link>. - In particular, if customized extent hooks reserve physical memory - (e.g. 1G huge pages), this is useful to control the allocation hook's - input size. The default is no limit.</para></listitem> - </varlistentry> - - <varlistentry id="arena.i.extent_hooks"> - <term> - <mallctl>arena.<i>.extent_hooks</mallctl> - (<type>extent_hooks_t *</type>) - <literal>rw</literal> - </term> - <listitem><para>Get or set the extent management hook functions for - arena <i>. The functions must be capable of operating on all - extant extents associated with arena <i>, usually by passing - unknown extents to the replaced functions. In practice, it is feasible - to control allocation for arenas explicitly created via <link - linkend="arenas.create"><mallctl>arenas.create</mallctl></link> such - that all extents originate from an application-supplied extent allocator - (by specifying the custom extent hook functions during arena creation), - but the automatically created arenas will have already created extents - prior to the application having an opportunity to take over extent - allocation.</para> - - <programlisting language="C"><![CDATA[ -typedef extent_hooks_s extent_hooks_t; -struct extent_hooks_s { - extent_alloc_t *alloc; - extent_dalloc_t *dalloc; - extent_destroy_t *destroy; - extent_commit_t *commit; - extent_decommit_t *decommit; - extent_purge_t *purge_lazy; - extent_purge_t *purge_forced; - extent_split_t *split; - extent_merge_t *merge; -};]]></programlisting> - <para>The <type>extent_hooks_t</type> structure comprises function - pointers which are described individually below. jemalloc uses these - functions to manage extent lifetime, which starts off with allocation of - mapped committed memory, in the simplest case followed by deallocation. - However, there are performance and platform reasons to retain extents - for later reuse. Cleanup attempts cascade from deallocation to decommit - to forced purging to lazy purging, which gives the extent management - functions opportunities to reject the most permanent cleanup operations - in favor of less permanent (and often less costly) operations. All - operations except allocation can be universally opted out of by setting - the hook pointers to <constant>NULL</constant>, or selectively opted out - of by returning failure. Note that once the extent hook is set, the - structure is accessed directly by the associated arenas, so it must - remain valid for the entire lifetime of the arenas.</para> - - <funcsynopsis><funcprototype> - <funcdef>typedef void *<function>(extent_alloc_t)</function></funcdef> - <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> - <paramdef>void *<parameter>new_addr</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>size_t <parameter>alignment</parameter></paramdef> - <paramdef>bool *<parameter>zero</parameter></paramdef> - <paramdef>bool *<parameter>commit</parameter></paramdef> - <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> - </funcprototype></funcsynopsis> - <literallayout></literallayout> - <para>An extent allocation function conforms to the - <type>extent_alloc_t</type> type and upon success returns a pointer to - <parameter>size</parameter> bytes of mapped memory on behalf of arena - <parameter>arena_ind</parameter> such that the extent's base address is - a multiple of <parameter>alignment</parameter>, as well as setting - <parameter>*zero</parameter> to indicate whether the extent is zeroed - and <parameter>*commit</parameter> to indicate whether the extent is - committed. Upon error the function returns <constant>NULL</constant> - and leaves <parameter>*zero</parameter> and - <parameter>*commit</parameter> unmodified. The - <parameter>size</parameter> parameter is always a multiple of the page - size. The <parameter>alignment</parameter> parameter is always a power - of two at least as large as the page size. Zeroing is mandatory if - <parameter>*zero</parameter> is true upon function entry. Committing is - mandatory if <parameter>*commit</parameter> is true upon function entry. - If <parameter>new_addr</parameter> is not <constant>NULL</constant>, the - returned pointer must be <parameter>new_addr</parameter> on success or - <constant>NULL</constant> on error. Committed memory may be committed - in absolute terms as on a system that does not overcommit, or in - implicit terms as on a system that overcommits and satisfies physical - memory needs on demand via soft page faults. Note that replacing the - default extent allocation function makes the arena's <link - linkend="arena.i.dss"><mallctl>arena.<i>.dss</mallctl></link> - setting irrelevant.</para> - - <funcsynopsis><funcprototype> - <funcdef>typedef bool <function>(extent_dalloc_t)</function></funcdef> - <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> - <paramdef>void *<parameter>addr</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>bool <parameter>committed</parameter></paramdef> - <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> - </funcprototype></funcsynopsis> - <literallayout></literallayout> - <para> - An extent deallocation function conforms to the - <type>extent_dalloc_t</type> type and deallocates an extent at given - <parameter>addr</parameter> and <parameter>size</parameter> with - <parameter>committed</parameter>/decommited memory as indicated, on - behalf of arena <parameter>arena_ind</parameter>, returning false upon - success. If the function returns true, this indicates opt-out from - deallocation; the virtual memory mapping associated with the extent - remains mapped, in the same commit state, and available for future use, - in which case it will be automatically retained for later reuse.</para> - - <funcsynopsis><funcprototype> - <funcdef>typedef void <function>(extent_destroy_t)</function></funcdef> - <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> - <paramdef>void *<parameter>addr</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>bool <parameter>committed</parameter></paramdef> - <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> - </funcprototype></funcsynopsis> - <literallayout></literallayout> - <para> - An extent destruction function conforms to the - <type>extent_destroy_t</type> type and unconditionally destroys an - extent at given <parameter>addr</parameter> and - <parameter>size</parameter> with - <parameter>committed</parameter>/decommited memory as indicated, on - behalf of arena <parameter>arena_ind</parameter>. This function may be - called to destroy retained extents during arena destruction (see <link - linkend="arena.i.destroy"><mallctl>arena.<i>.destroy</mallctl></link>).</para> - - <funcsynopsis><funcprototype> - <funcdef>typedef bool <function>(extent_commit_t)</function></funcdef> - <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> - <paramdef>void *<parameter>addr</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>size_t <parameter>offset</parameter></paramdef> - <paramdef>size_t <parameter>length</parameter></paramdef> - <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> - </funcprototype></funcsynopsis> - <literallayout></literallayout> - <para>An extent commit function conforms to the - <type>extent_commit_t</type> type and commits zeroed physical memory to - back pages within an extent at given <parameter>addr</parameter> and - <parameter>size</parameter> at <parameter>offset</parameter> bytes, - extending for <parameter>length</parameter> on behalf of arena - <parameter>arena_ind</parameter>, returning false upon success. - Committed memory may be committed in absolute terms as on a system that - does not overcommit, or in implicit terms as on a system that - overcommits and satisfies physical memory needs on demand via soft page - faults. If the function returns true, this indicates insufficient - physical memory to satisfy the request.</para> - - <funcsynopsis><funcprototype> - <funcdef>typedef bool <function>(extent_decommit_t)</function></funcdef> - <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> - <paramdef>void *<parameter>addr</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>size_t <parameter>offset</parameter></paramdef> - <paramdef>size_t <parameter>length</parameter></paramdef> - <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> - </funcprototype></funcsynopsis> - <literallayout></literallayout> - <para>An extent decommit function conforms to the - <type>extent_decommit_t</type> type and decommits any physical memory - that is backing pages within an extent at given - <parameter>addr</parameter> and <parameter>size</parameter> at - <parameter>offset</parameter> bytes, extending for - <parameter>length</parameter> on behalf of arena - <parameter>arena_ind</parameter>, returning false upon success, in which - case the pages will be committed via the extent commit function before - being reused. If the function returns true, this indicates opt-out from - decommit; the memory remains committed and available for future use, in - which case it will be automatically retained for later reuse.</para> - - <funcsynopsis><funcprototype> - <funcdef>typedef bool <function>(extent_purge_t)</function></funcdef> - <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> - <paramdef>void *<parameter>addr</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>size_t <parameter>offset</parameter></paramdef> - <paramdef>size_t <parameter>length</parameter></paramdef> - <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> - </funcprototype></funcsynopsis> - <literallayout></literallayout> - <para>An extent purge function conforms to the - <type>extent_purge_t</type> type and discards physical pages - within the virtual memory mapping associated with an extent at given - <parameter>addr</parameter> and <parameter>size</parameter> at - <parameter>offset</parameter> bytes, extending for - <parameter>length</parameter> on behalf of arena - <parameter>arena_ind</parameter>. A lazy extent purge function (e.g. - implemented via - <function>madvise(<parameter>...</parameter><parameter><constant>MADV_FREE</constant></parameter>)</function>) - can delay purging indefinitely and leave the pages within the purged - virtual memory range in an indeterminite state, whereas a forced extent - purge function immediately purges, and the pages within the virtual - memory range will be zero-filled the next time they are accessed. If - the function returns true, this indicates failure to purge.</para> - - <funcsynopsis><funcprototype> - <funcdef>typedef bool <function>(extent_split_t)</function></funcdef> - <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> - <paramdef>void *<parameter>addr</parameter></paramdef> - <paramdef>size_t <parameter>size</parameter></paramdef> - <paramdef>size_t <parameter>size_a</parameter></paramdef> - <paramdef>size_t <parameter>size_b</parameter></paramdef> - <paramdef>bool <parameter>committed</parameter></paramdef> - <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> - </funcprototype></funcsynopsis> - <literallayout></literallayout> - <para>An extent split function conforms to the - <type>extent_split_t</type> type and optionally splits an extent at - given <parameter>addr</parameter> and <parameter>size</parameter> into - two adjacent extents, the first of <parameter>size_a</parameter> bytes, - and the second of <parameter>size_b</parameter> bytes, operating on - <parameter>committed</parameter>/decommitted memory as indicated, on - behalf of arena <parameter>arena_ind</parameter>, returning false upon - success. If the function returns true, this indicates that the extent - remains unsplit and therefore should continue to be operated on as a - whole.</para> - - <funcsynopsis><funcprototype> - <funcdef>typedef bool <function>(extent_merge_t)</function></funcdef> - <paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef> - <paramdef>void *<parameter>addr_a</parameter></paramdef> - <paramdef>size_t <parameter>size_a</parameter></paramdef> - <paramdef>void *<parameter>addr_b</parameter></paramdef> - <paramdef>size_t <parameter>size_b</parameter></paramdef> - <paramdef>bool <parameter>committed</parameter></paramdef> - <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> - </funcprototype></funcsynopsis> - <literallayout></literallayout> - <para>An extent merge function conforms to the - <type>extent_merge_t</type> type and optionally merges adjacent extents, - at given <parameter>addr_a</parameter> and <parameter>size_a</parameter> - with given <parameter>addr_b</parameter> and - <parameter>size_b</parameter> into one contiguous extent, operating on - <parameter>committed</parameter>/decommitted memory as indicated, on - behalf of arena <parameter>arena_ind</parameter>, returning false upon - success. If the function returns true, this indicates that the extents - remain distinct mappings and therefore should continue to be operated on - independently.</para> - </listitem> - </varlistentry> - - <varlistentry id="arenas.narenas"> - <term> - <mallctl>arenas.narenas</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - </term> - <listitem><para>Current limit on number of arenas.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.dirty_decay_ms"> - <term> - <mallctl>arenas.dirty_decay_ms</mallctl> - (<type>ssize_t</type>) - <literal>rw</literal> - </term> - <listitem><para>Current default per-arena approximate time in - milliseconds from the creation of a set of unused dirty pages until an - equivalent set of unused dirty pages is purged and/or reused, used to - initialize <link - linkend="arena.i.dirty_decay_ms"><mallctl>arena.<i>.dirty_decay_ms</mallctl></link> - during arena creation. See <link - linkend="opt.dirty_decay_ms"><mallctl>opt.dirty_decay_ms</mallctl></link> - for additional information.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.muzzy_decay_ms"> - <term> - <mallctl>arenas.muzzy_decay_ms</mallctl> - (<type>ssize_t</type>) - <literal>rw</literal> - </term> - <listitem><para>Current default per-arena approximate time in - milliseconds from the creation of a set of unused muzzy pages until an - equivalent set of unused muzzy pages is purged and/or reused, used to - initialize <link - linkend="arena.i.muzzy_decay_ms"><mallctl>arena.<i>.muzzy_decay_ms</mallctl></link> - during arena creation. See <link - linkend="opt.muzzy_decay_ms"><mallctl>opt.muzzy_decay_ms</mallctl></link> - for additional information.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.quantum"> - <term> - <mallctl>arenas.quantum</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Quantum size.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.page"> - <term> - <mallctl>arenas.page</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Page size.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.tcache_max"> - <term> - <mallctl>arenas.tcache_max</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Maximum thread-cached size class.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.nbins"> - <term> - <mallctl>arenas.nbins</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - </term> - <listitem><para>Number of bin size classes.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.nhbins"> - <term> - <mallctl>arenas.nhbins</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - </term> - <listitem><para>Total number of thread cache bin size - classes.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.bin.i.size"> - <term> - <mallctl>arenas.bin.<i>.size</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Maximum size supported by size class.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.bin.i.nregs"> - <term> - <mallctl>arenas.bin.<i>.nregs</mallctl> - (<type>uint32_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Number of regions per slab.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.bin.i.slab_size"> - <term> - <mallctl>arenas.bin.<i>.slab_size</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Number of bytes per slab.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.nlextents"> - <term> - <mallctl>arenas.nlextents</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - </term> - <listitem><para>Total number of large size classes.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.lextent.i.size"> - <term> - <mallctl>arenas.lextent.<i>.size</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Maximum size supported by this large size - class.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.create"> - <term> - <mallctl>arenas.create</mallctl> - (<type>unsigned</type>, <type>extent_hooks_t *</type>) - <literal>rw</literal> - </term> - <listitem><para>Explicitly create a new arena outside the range of - automatically managed arenas, with optionally specified extent hooks, - and return the new arena index.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.lookup"> - <term> - <mallctl>arenas.lookup</mallctl> - (<type>unsigned</type>, <type>void*</type>) - <literal>rw</literal> - </term> - <listitem><para>Index of the arena to which an allocation belongs to.</para></listitem> - </varlistentry> - - <varlistentry id="prof.thread_active_init"> - <term> - <mallctl>prof.thread_active_init</mallctl> - (<type>bool</type>) - <literal>rw</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Control the initial setting for <link - linkend="thread.prof.active"><mallctl>thread.prof.active</mallctl></link> - in newly created threads. See the <link - linkend="opt.prof_thread_active_init"><mallctl>opt.prof_thread_active_init</mallctl></link> - option for additional information.</para></listitem> - </varlistentry> - - <varlistentry id="prof.active"> - <term> - <mallctl>prof.active</mallctl> - (<type>bool</type>) - <literal>rw</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Control whether sampling is currently active. See the - <link - linkend="opt.prof_active"><mallctl>opt.prof_active</mallctl></link> - option for additional information, as well as the interrelated <link - linkend="thread.prof.active"><mallctl>thread.prof.active</mallctl></link> - mallctl.</para></listitem> - </varlistentry> - - <varlistentry id="prof.dump"> - <term> - <mallctl>prof.dump</mallctl> - (<type>const char *</type>) - <literal>-w</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Dump a memory profile to the specified file, or if NULL - is specified, to a file according to the pattern - <filename><prefix>.<pid>.<seq>.m<mseq>.heap</filename>, - where <literal><prefix></literal> is controlled by the - <link - linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> - option.</para></listitem> - </varlistentry> - - <varlistentry id="prof.gdump"> - <term> - <mallctl>prof.gdump</mallctl> - (<type>bool</type>) - <literal>rw</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>When enabled, trigger a memory profile dump every time - the total virtual memory exceeds the previous maximum. Profiles are - dumped to files named according to the pattern - <filename><prefix>.<pid>.<seq>.u<useq>.heap</filename>, - where <literal><prefix></literal> is controlled by the <link - linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> - option.</para></listitem> - </varlistentry> - - <varlistentry id="prof.reset"> - <term> - <mallctl>prof.reset</mallctl> - (<type>size_t</type>) - <literal>-w</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Reset all memory profile statistics, and optionally - update the sample rate (see <link - linkend="opt.lg_prof_sample"><mallctl>opt.lg_prof_sample</mallctl></link> - and <link - linkend="prof.lg_sample"><mallctl>prof.lg_sample</mallctl></link>). - </para></listitem> - </varlistentry> - - <varlistentry id="prof.lg_sample"> - <term> - <mallctl>prof.lg_sample</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Get the current sample rate (see <link - linkend="opt.lg_prof_sample"><mallctl>opt.lg_prof_sample</mallctl></link>). - </para></listitem> - </varlistentry> - - <varlistentry id="prof.interval"> - <term> - <mallctl>prof.interval</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-prof</option>] - </term> - <listitem><para>Average number of bytes allocated between - interval-based profile dumps. See the - <link - linkend="opt.lg_prof_interval"><mallctl>opt.lg_prof_interval</mallctl></link> - option for additional information.</para></listitem> - </varlistentry> - - <varlistentry id="stats.allocated"> - <term> - <mallctl>stats.allocated</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Total number of bytes allocated by the - application.</para></listitem> - </varlistentry> - - <varlistentry id="stats.active"> - <term> - <mallctl>stats.active</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Total number of bytes in active pages allocated by the - application. This is a multiple of the page size, and greater than or - equal to <link - linkend="stats.allocated"><mallctl>stats.allocated</mallctl></link>. - This does not include <link linkend="stats.arenas.i.pdirty"> - <mallctl>stats.arenas.<i>.pdirty</mallctl></link>, - <link linkend="stats.arenas.i.pmuzzy"> - <mallctl>stats.arenas.<i>.pmuzzy</mallctl></link>, nor pages - entirely devoted to allocator metadata.</para></listitem> - </varlistentry> - - <varlistentry id="stats.metadata"> - <term> - <mallctl>stats.metadata</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Total number of bytes dedicated to metadata, which - comprise base allocations used for bootstrap-sensitive allocator - metadata structures (see <link - linkend="stats.arenas.i.base"><mallctl>stats.arenas.<i>.base</mallctl></link>) - and internal allocations (see <link - linkend="stats.arenas.i.internal"><mallctl>stats.arenas.<i>.internal</mallctl></link>). - Transparent huge page (enabled with <link - linkend="opt.metadata_thp">opt.metadata_thp</link>) usage is not - considered.</para></listitem> - </varlistentry> - - <varlistentry id="stats.metadata_thp"> - <term> - <mallctl>stats.metadata_thp</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of transparent huge pages (THP) used for - metadata. See <link - linkend="stats.metadata"><mallctl>stats.metadata</mallctl></link> and - <link linkend="opt.metadata_thp">opt.metadata_thp</link>) for - details.</para></listitem> - </varlistentry> - - <varlistentry id="stats.resident"> - <term> - <mallctl>stats.resident</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Maximum number of bytes in physically resident data - pages mapped by the allocator, comprising all pages dedicated to - allocator metadata, pages backing active allocations, and unused dirty - pages. This is a maximum rather than precise because pages may not - actually be physically resident if they correspond to demand-zeroed - virtual memory that has not yet been touched. This is a multiple of the - page size, and is larger than <link - linkend="stats.active"><mallctl>stats.active</mallctl></link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.mapped"> - <term> - <mallctl>stats.mapped</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Total number of bytes in active extents mapped by the - allocator. This is larger than <link - linkend="stats.active"><mallctl>stats.active</mallctl></link>. This - does not include inactive extents, even those that contain unused dirty - pages, which means that there is no strict ordering between this and - <link - linkend="stats.resident"><mallctl>stats.resident</mallctl></link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.retained"> - <term> - <mallctl>stats.retained</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Total number of bytes in virtual memory mappings that - were retained rather than being returned to the operating system via - e.g. <citerefentry><refentrytitle>munmap</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> or similar. Retained virtual - memory is typically untouched, decommitted, or purged, so it has no - strongly associated physical memory (see <link - linkend="arena.i.extent_hooks">extent hooks</link> for details). - Retained memory is excluded from mapped memory statistics, e.g. <link - linkend="stats.mapped"><mallctl>stats.mapped</mallctl></link>. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.background_thread.num_threads"> - <term> - <mallctl>stats.background_thread.num_threads</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para> Number of <link linkend="background_thread">background - threads</link> running currently.</para></listitem> - </varlistentry> - - <varlistentry id="stats.background_thread.num_runs"> - <term> - <mallctl>stats.background_thread.num_runs</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para> Total number of runs from all <link - linkend="background_thread">background threads</link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.background_thread.run_interval"> - <term> - <mallctl>stats.background_thread.run_interval</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para> Average run interval in nanoseconds of <link - linkend="background_thread">background threads</link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.mutexes.ctl"> - <term> - <mallctl>stats.mutexes.ctl.{counter};</mallctl> - (<type>counter specific type</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Statistics on <varname>ctl</varname> mutex (global - scope; mallctl related). <mallctl>{counter}</mallctl> is one of the - counters below:</para> - <varlistentry id="mutex_counters"> - <listitem><para><varname>num_ops</varname> (<type>uint64_t</type>): - Total number of lock acquisition operations on this mutex.</para> - - <para><varname>num_spin_acq</varname> (<type>uint64_t</type>): Number - of times the mutex was spin-acquired. When the mutex is currently - locked and cannot be acquired immediately, a short period of - spin-retry within jemalloc will be performed. Acquired through spin - generally means the contention was lightweight and not causing context - switches.</para> - - <para><varname>num_wait</varname> (<type>uint64_t</type>): Number of - times the mutex was wait-acquired, which means the mutex contention - was not solved by spin-retry, and blocking operation was likely - involved in order to acquire the mutex. This event generally implies - higher cost / longer delay, and should be investigated if it happens - often.</para> - - <para><varname>max_wait_time</varname> (<type>uint64_t</type>): - Maximum length of time in nanoseconds spent on a single wait-acquired - lock operation. Note that to avoid profiling overhead on the common - path, this does not consider spin-acquired cases.</para> - - <para><varname>total_wait_time</varname> (<type>uint64_t</type>): - Cumulative time in nanoseconds spent on wait-acquired lock operations. - Similarly, spin-acquired cases are not considered.</para> - - <para><varname>max_num_thds</varname> (<type>uint32_t</type>): Maximum - number of threads waiting on this mutex simultaneously. Similarly, - spin-acquired cases are not considered.</para> - - <para><varname>num_owner_switch</varname> (<type>uint64_t</type>): - Number of times the current mutex owner is different from the previous - one. This event does not generally imply an issue; rather it is an - indicator of how often the protected data are accessed by different - threads. - </para> - </listitem> - </varlistentry> - </listitem> - </varlistentry> - - <varlistentry id="stats.mutexes.background_thread"> - <term> - <mallctl>stats.mutexes.background_thread.{counter}</mallctl> - (<type>counter specific type</type>) <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Statistics on <varname>background_thread</varname> mutex - (global scope; <link - linkend="background_thread"><mallctl>background_thread</mallctl></link> - related). <mallctl>{counter}</mallctl> is one of the counters in <link - linkend="mutex_counters">mutex profiling - counters</link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.mutexes.prof"> - <term> - <mallctl>stats.mutexes.prof.{counter}</mallctl> - (<type>counter specific type</type>) <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Statistics on <varname>prof</varname> mutex (global - scope; profiling related). <mallctl>{counter}</mallctl> is one of the - counters in <link linkend="mutex_counters">mutex profiling - counters</link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.mutexes.reset"> - <term> - <mallctl>stats.mutexes.reset</mallctl> - (<type>void</type>) <literal>--</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Reset all mutex profile statistics, including global - mutexes, arena mutexes and bin mutexes.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.dss"> - <term> - <mallctl>stats.arenas.<i>.dss</mallctl> - (<type>const char *</type>) - <literal>r-</literal> - </term> - <listitem><para>dss (<citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry>) allocation precedence as - related to <citerefentry><refentrytitle>mmap</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> allocation. See <link - linkend="opt.dss"><mallctl>opt.dss</mallctl></link> for details. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.dirty_decay_ms"> - <term> - <mallctl>stats.arenas.<i>.dirty_decay_ms</mallctl> - (<type>ssize_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Approximate time in milliseconds from the creation of a - set of unused dirty pages until an equivalent set of unused dirty pages - is purged and/or reused. See <link - linkend="opt.dirty_decay_ms"><mallctl>opt.dirty_decay_ms</mallctl></link> - for details.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.muzzy_decay_ms"> - <term> - <mallctl>stats.arenas.<i>.muzzy_decay_ms</mallctl> - (<type>ssize_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Approximate time in milliseconds from the creation of a - set of unused muzzy pages until an equivalent set of unused muzzy pages - is purged and/or reused. See <link - linkend="opt.muzzy_decay_ms"><mallctl>opt.muzzy_decay_ms</mallctl></link> - for details.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.nthreads"> - <term> - <mallctl>stats.arenas.<i>.nthreads</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - </term> - <listitem><para>Number of threads currently assigned to - arena.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.uptime"> - <term> - <mallctl>stats.arenas.<i>.uptime</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Time elapsed (in nanoseconds) since the arena was - created. If <i> equals <constant>0</constant> or - <constant>MALLCTL_ARENAS_ALL</constant>, this is the uptime since malloc - initialization.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.pactive"> - <term> - <mallctl>stats.arenas.<i>.pactive</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Number of pages in active extents.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.pdirty"> - <term> - <mallctl>stats.arenas.<i>.pdirty</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Number of pages within unused extents that are - potentially dirty, and for which <function>madvise()</function> or - similar has not been called. See <link - linkend="opt.dirty_decay_ms"><mallctl>opt.dirty_decay_ms</mallctl></link> - for a description of dirty pages.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.pmuzzy"> - <term> - <mallctl>stats.arenas.<i>.pmuzzy</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Number of pages within unused extents that are muzzy. - See <link - linkend="opt.muzzy_decay_ms"><mallctl>opt.muzzy_decay_ms</mallctl></link> - for a description of muzzy pages.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.mapped"> - <term> - <mallctl>stats.arenas.<i>.mapped</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of mapped bytes.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.retained"> - <term> - <mallctl>stats.arenas.<i>.retained</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of retained bytes. See <link - linkend="stats.retained"><mallctl>stats.retained</mallctl></link> for - details.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.base"> - <term> - <mallctl>stats.arenas.<i>.base</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para> - Number of bytes dedicated to bootstrap-sensitive allocator metadata - structures.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.internal"> - <term> - <mallctl>stats.arenas.<i>.internal</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of bytes dedicated to internal allocations. - Internal allocations differ from application-originated allocations in - that they are for internal use, and that they are omitted from heap - profiles.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.metadata_thp"> - <term> - <mallctl>stats.arenas.<i>.metadata_thp</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of transparent huge pages (THP) used for - metadata. See <link linkend="opt.metadata_thp">opt.metadata_thp</link> - for details.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.resident"> - <term> - <mallctl>stats.arenas.<i>.resident</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Maximum number of bytes in physically resident data - pages mapped by the arena, comprising all pages dedicated to allocator - metadata, pages backing active allocations, and unused dirty pages. - This is a maximum rather than precise because pages may not actually be - physically resident if they correspond to demand-zeroed virtual memory - that has not yet been touched. This is a multiple of the page - size.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.dirty_npurge"> - <term> - <mallctl>stats.arenas.<i>.dirty_npurge</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of dirty page purge sweeps performed. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.dirty_nmadvise"> - <term> - <mallctl>stats.arenas.<i>.dirty_nmadvise</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of <function>madvise()</function> or similar - calls made to purge dirty pages.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.dirty_purged"> - <term> - <mallctl>stats.arenas.<i>.dirty_purged</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of dirty pages purged.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.muzzy_npurge"> - <term> - <mallctl>stats.arenas.<i>.muzzy_npurge</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of muzzy page purge sweeps performed. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.muzzy_nmadvise"> - <term> - <mallctl>stats.arenas.<i>.muzzy_nmadvise</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of <function>madvise()</function> or similar - calls made to purge muzzy pages.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.muzzy_purged"> - <term> - <mallctl>stats.arenas.<i>.muzzy_purged</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of muzzy pages purged.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.small.allocated"> - <term> - <mallctl>stats.arenas.<i>.small.allocated</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of bytes currently allocated by small objects. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.small.nmalloc"> - <term> - <mallctl>stats.arenas.<i>.small.nmalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of times a small allocation was - requested from the arena's bins, whether to fill the relevant tcache if - <link linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is - enabled, or to directly satisfy an allocation request - otherwise.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.small.ndalloc"> - <term> - <mallctl>stats.arenas.<i>.small.ndalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of times a small allocation was - returned to the arena's bins, whether to flush the relevant tcache if - <link linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is - enabled, or to directly deallocate an allocation - otherwise.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.small.nrequests"> - <term> - <mallctl>stats.arenas.<i>.small.nrequests</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of allocation requests satisfied by - all bin size classes.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.large.allocated"> - <term> - <mallctl>stats.arenas.<i>.large.allocated</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Number of bytes currently allocated by large objects. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.large.nmalloc"> - <term> - <mallctl>stats.arenas.<i>.large.nmalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of times a large extent was allocated - from the arena, whether to fill the relevant tcache if <link - linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is enabled and - the size class is within the range being cached, or to directly satisfy - an allocation request otherwise.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.large.ndalloc"> - <term> - <mallctl>stats.arenas.<i>.large.ndalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of times a large extent was returned - to the arena, whether to flush the relevant tcache if <link - linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is enabled and - the size class is within the range being cached, or to directly - deallocate an allocation otherwise.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.large.nrequests"> - <term> - <mallctl>stats.arenas.<i>.large.nrequests</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of allocation requests satisfied by - all large size classes.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.nmalloc"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.nmalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of times a bin region of the - corresponding size class was allocated from the arena, whether to fill - the relevant tcache if <link - linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is enabled, or - to directly satisfy an allocation request otherwise.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.ndalloc"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.ndalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of times a bin region of the - corresponding size class was returned to the arena, whether to flush the - relevant tcache if <link - linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is enabled, or - to directly deallocate an allocation otherwise.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.nrequests"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.nrequests</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of allocation requests satisfied by - bin regions of the corresponding size class.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.curregs"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.curregs</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Current number of regions for this size - class.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.nfills"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.nfills</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Cumulative number of tcache fills.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.nflushes"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.nflushes</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - </term> - <listitem><para>Cumulative number of tcache flushes.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.nslabs"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.nslabs</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of slabs created.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.nreslabs"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.nreslabs</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of times the current slab from which - to allocate changed.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.j.curslabs"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.curslabs</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Current number of slabs.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.bins.mutex"> - <term> - <mallctl>stats.arenas.<i>.bins.<j>.mutex.{counter}</mallctl> - (<type>counter specific type</type>) <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Statistics on - <varname>arena.<i>.bins.<j></varname> mutex (arena bin - scope; bin operation related). <mallctl>{counter}</mallctl> is one of - the counters in <link linkend="mutex_counters">mutex profiling - counters</link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.lextents.j.nmalloc"> - <term> - <mallctl>stats.arenas.<i>.lextents.<j>.nmalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of times a large extent of the - corresponding size class was allocated from the arena, whether to fill - the relevant tcache if <link - linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is enabled and - the size class is within the range being cached, or to directly satisfy - an allocation request otherwise.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.lextents.j.ndalloc"> - <term> - <mallctl>stats.arenas.<i>.lextents.<j>.ndalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of times a large extent of the - corresponding size class was returned to the arena, whether to flush the - relevant tcache if <link - linkend="opt.tcache"><mallctl>opt.tcache</mallctl></link> is enabled and - the size class is within the range being cached, or to directly - deallocate an allocation otherwise.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.lextents.j.nrequests"> - <term> - <mallctl>stats.arenas.<i>.lextents.<j>.nrequests</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Cumulative number of allocation requests satisfied by - large extents of the corresponding size class.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.lextents.j.curlextents"> - <term> - <mallctl>stats.arenas.<i>.lextents.<j>.curlextents</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Current number of large allocations for this size class. - </para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.mutexes.large"> - <term> - <mallctl>stats.arenas.<i>.mutexes.large.{counter}</mallctl> - (<type>counter specific type</type>) <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Statistics on <varname>arena.<i>.large</varname> - mutex (arena scope; large allocation related). - <mallctl>{counter}</mallctl> is one of the counters in <link - linkend="mutex_counters">mutex profiling - counters</link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.mutexes.extent_avail"> - <term> - <mallctl>stats.arenas.<i>.mutexes.extent_avail.{counter}</mallctl> - (<type>counter specific type</type>) <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Statistics on <varname>arena.<i>.extent_avail - </varname> mutex (arena scope; extent avail related). - <mallctl>{counter}</mallctl> is one of the counters in <link - linkend="mutex_counters">mutex profiling - counters</link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.mutexes.extents_dirty"> - <term> - <mallctl>stats.arenas.<i>.mutexes.extents_dirty.{counter}</mallctl> - (<type>counter specific type</type>) <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Statistics on <varname>arena.<i>.extents_dirty - </varname> mutex (arena scope; dirty extents related). - <mallctl>{counter}</mallctl> is one of the counters in <link - linkend="mutex_counters">mutex profiling - counters</link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.mutexes.extents_muzzy"> - <term> - <mallctl>stats.arenas.<i>.mutexes.extents_muzzy.{counter}</mallctl> - (<type>counter specific type</type>) <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Statistics on <varname>arena.<i>.extents_muzzy - </varname> mutex (arena scope; muzzy extents related). - <mallctl>{counter}</mallctl> is one of the counters in <link - linkend="mutex_counters">mutex profiling - counters</link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.mutexes.extents_retained"> - <term> - <mallctl>stats.arenas.<i>.mutexes.extents_retained.{counter}</mallctl> - (<type>counter specific type</type>) <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Statistics on <varname>arena.<i>.extents_retained - </varname> mutex (arena scope; retained extents related). - <mallctl>{counter}</mallctl> is one of the counters in <link - linkend="mutex_counters">mutex profiling - counters</link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.mutexes.decay_dirty"> - <term> - <mallctl>stats.arenas.<i>.mutexes.decay_dirty.{counter}</mallctl> - (<type>counter specific type</type>) <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Statistics on <varname>arena.<i>.decay_dirty - </varname> mutex (arena scope; decay for dirty pages related). - <mallctl>{counter}</mallctl> is one of the counters in <link - linkend="mutex_counters">mutex profiling - counters</link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.mutexes.decay_muzzy"> - <term> - <mallctl>stats.arenas.<i>.mutexes.decay_muzzy.{counter}</mallctl> - (<type>counter specific type</type>) <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Statistics on <varname>arena.<i>.decay_muzzy - </varname> mutex (arena scope; decay for muzzy pages related). - <mallctl>{counter}</mallctl> is one of the counters in <link - linkend="mutex_counters">mutex profiling - counters</link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.mutexes.base"> - <term> - <mallctl>stats.arenas.<i>.mutexes.base.{counter}</mallctl> - (<type>counter specific type</type>) <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Statistics on <varname>arena.<i>.base</varname> - mutex (arena scope; base allocator related). - <mallctl>{counter}</mallctl> is one of the counters in <link - linkend="mutex_counters">mutex profiling - counters</link>.</para></listitem> - </varlistentry> - - <varlistentry id="stats.arenas.i.mutexes.tcache_list"> - <term> - <mallctl>stats.arenas.<i>.mutexes.tcache_list.{counter}</mallctl> - (<type>counter specific type</type>) <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Statistics on - <varname>arena.<i>.tcache_list</varname> mutex (arena scope; - tcache to arena association related). This mutex is expected to be - accessed less often. <mallctl>{counter}</mallctl> is one of the - counters in <link linkend="mutex_counters">mutex profiling - counters</link>.</para></listitem> - </varlistentry> - - </variablelist> - </refsect1> - <refsect1 id="heap_profile_format"> - <title>HEAP PROFILE FORMAT</title> - <para>Although the heap profiling functionality was originally designed to - be compatible with the - <command>pprof</command> command that is developed as part of the <ulink - url="http://code.google.com/p/gperftools/">gperftools - package</ulink>, the addition of per thread heap profiling functionality - required a different heap profile format. The <command>jeprof</command> - command is derived from <command>pprof</command>, with enhancements to - support the heap profile format described here.</para> - - <para>In the following hypothetical heap profile, <constant>[...]</constant> - indicates elision for the sake of compactness. <programlisting><![CDATA[ -heap_v2/524288 - t*: 28106: 56637512 [0: 0] - [...] - t3: 352: 16777344 [0: 0] - [...] - t99: 17754: 29341640 [0: 0] - [...] -@ 0x5f86da8 0x5f5a1dc [...] 0x29e4d4e 0xa200316 0xabb2988 [...] - t*: 13: 6688 [0: 0] - t3: 12: 6496 [0: ] - t99: 1: 192 [0: 0] -[...] - -MAPPED_LIBRARIES: -[...]]]></programlisting> The following matches the above heap profile, but most -tokens are replaced with <constant><description></constant> to indicate -descriptions of the corresponding fields. <programlisting><![CDATA[ -<heap_profile_format_version>/<mean_sample_interval> - <aggregate>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>] - [...] - <thread_3_aggregate>: <curobjs>: <curbytes>[<cumobjs>: <cumbytes>] - [...] - <thread_99_aggregate>: <curobjs>: <curbytes>[<cumobjs>: <cumbytes>] - [...] -@ <top_frame> <frame> [...] <frame> <frame> <frame> [...] - <backtrace_aggregate>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>] - <backtrace_thread_3>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>] - <backtrace_thread_99>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>] -[...] - -MAPPED_LIBRARIES: -</proc/<pid>/maps>]]></programlisting></para> - </refsect1> - - <refsect1 id="debugging_malloc_problems"> - <title>DEBUGGING MALLOC PROBLEMS</title> - <para>When debugging, it is a good idea to configure/build jemalloc with - the <option>--enable-debug</option> and <option>--enable-fill</option> - options, and recompile the program with suitable options and symbols for - debugger support. When so configured, jemalloc incorporates a wide variety - of run-time assertions that catch application errors such as double-free, - write-after-free, etc.</para> - - <para>Programs often accidentally depend on <quote>uninitialized</quote> - memory actually being filled with zero bytes. Junk filling - (see the <link linkend="opt.junk"><mallctl>opt.junk</mallctl></link> - option) tends to expose such bugs in the form of obviously incorrect - results and/or coredumps. Conversely, zero - filling (see the <link - linkend="opt.zero"><mallctl>opt.zero</mallctl></link> option) eliminates - the symptoms of such bugs. Between these two options, it is usually - possible to quickly detect, diagnose, and eliminate such bugs.</para> - - <para>This implementation does not provide much detail about the problems - it detects, because the performance impact for storing such information - would be prohibitive.</para> - </refsect1> - <refsect1 id="diagnostic_messages"> - <title>DIAGNOSTIC MESSAGES</title> - <para>If any of the memory allocation/deallocation functions detect an - error or warning condition, a message will be printed to file descriptor - <constant>STDERR_FILENO</constant>. Errors will result in the process - dumping core. If the <link - linkend="opt.abort"><mallctl>opt.abort</mallctl></link> option is set, most - warnings are treated as errors.</para> - - <para>The <varname>malloc_message</varname> variable allows the programmer - to override the function which emits the text strings forming the errors - and warnings if for some reason the <constant>STDERR_FILENO</constant> file - descriptor is not suitable for this. - <function>malloc_message()</function> takes the - <parameter>cbopaque</parameter> pointer argument that is - <constant>NULL</constant> unless overridden by the arguments in a call to - <function>malloc_stats_print()</function>, followed by a string - pointer. Please note that doing anything which tries to allocate memory in - this function is likely to result in a crash or deadlock.</para> - - <para>All messages are prefixed by - <quote><computeroutput><jemalloc>: </computeroutput></quote>.</para> - </refsect1> - <refsect1 id="return_values"> - <title>RETURN VALUES</title> - <refsect2> - <title>Standard API</title> - <para>The <function>malloc()</function> and - <function>calloc()</function> functions return a pointer to the - allocated memory if successful; otherwise a <constant>NULL</constant> - pointer is returned and <varname>errno</varname> is set to - <errorname>ENOMEM</errorname>.</para> - - <para>The <function>posix_memalign()</function> function - returns the value 0 if successful; otherwise it returns an error value. - The <function>posix_memalign()</function> function will fail - if: - <variablelist> - <varlistentry> - <term><errorname>EINVAL</errorname></term> - - <listitem><para>The <parameter>alignment</parameter> parameter is - not a power of 2 at least as large as - <code language="C">sizeof(<type>void *</type>)</code>. - </para></listitem> - </varlistentry> - <varlistentry> - <term><errorname>ENOMEM</errorname></term> - - <listitem><para>Memory allocation error.</para></listitem> - </varlistentry> - </variablelist> - </para> - - <para>The <function>aligned_alloc()</function> function returns - a pointer to the allocated memory if successful; otherwise a - <constant>NULL</constant> pointer is returned and - <varname>errno</varname> is set. The - <function>aligned_alloc()</function> function will fail if: - <variablelist> - <varlistentry> - <term><errorname>EINVAL</errorname></term> - - <listitem><para>The <parameter>alignment</parameter> parameter is - not a power of 2. - </para></listitem> - </varlistentry> - <varlistentry> - <term><errorname>ENOMEM</errorname></term> - - <listitem><para>Memory allocation error.</para></listitem> - </varlistentry> - </variablelist> - </para> - - <para>The <function>realloc()</function> function returns a - pointer, possibly identical to <parameter>ptr</parameter>, to the - allocated memory if successful; otherwise a <constant>NULL</constant> - pointer is returned, and <varname>errno</varname> is set to - <errorname>ENOMEM</errorname> if the error was the result of an - allocation failure. The <function>realloc()</function> - function always leaves the original buffer intact when an error occurs. - </para> - - <para>The <function>free()</function> function returns no - value.</para> - </refsect2> - <refsect2> - <title>Non-standard API</title> - <para>The <function>mallocx()</function> and - <function>rallocx()</function> functions return a pointer to - the allocated memory if successful; otherwise a <constant>NULL</constant> - pointer is returned to indicate insufficient contiguous memory was - available to service the allocation request. </para> - - <para>The <function>xallocx()</function> function returns the - real size of the resulting resized allocation pointed to by - <parameter>ptr</parameter>, which is a value less than - <parameter>size</parameter> if the allocation could not be adequately - grown in place. </para> - - <para>The <function>sallocx()</function> function returns the - real size of the allocation pointed to by <parameter>ptr</parameter>. - </para> - - <para>The <function>nallocx()</function> returns the real size - that would result from a successful equivalent - <function>mallocx()</function> function call, or zero if - insufficient memory is available to perform the size computation. </para> - - <para>The <function>mallctl()</function>, - <function>mallctlnametomib()</function>, and - <function>mallctlbymib()</function> functions return 0 on - success; otherwise they return an error value. The functions will fail - if: - <variablelist> - <varlistentry> - <term><errorname>EINVAL</errorname></term> - - <listitem><para><parameter>newp</parameter> is not - <constant>NULL</constant>, and <parameter>newlen</parameter> is too - large or too small. Alternatively, <parameter>*oldlenp</parameter> - is too large or too small; in this case as much data as possible - are read despite the error.</para></listitem> - </varlistentry> - <varlistentry> - <term><errorname>ENOENT</errorname></term> - - <listitem><para><parameter>name</parameter> or - <parameter>mib</parameter> specifies an unknown/invalid - value.</para></listitem> - </varlistentry> - <varlistentry> - <term><errorname>EPERM</errorname></term> - - <listitem><para>Attempt to read or write void value, or attempt to - write read-only value.</para></listitem> - </varlistentry> - <varlistentry> - <term><errorname>EAGAIN</errorname></term> - - <listitem><para>A memory allocation failure - occurred.</para></listitem> - </varlistentry> - <varlistentry> - <term><errorname>EFAULT</errorname></term> - - <listitem><para>An interface with side effects failed in some way - not directly related to <function>mallctl*()</function> - read/write processing.</para></listitem> - </varlistentry> - </variablelist> - </para> - - <para>The <function>malloc_usable_size()</function> function - returns the usable size of the allocation pointed to by - <parameter>ptr</parameter>. </para> - </refsect2> - </refsect1> - <refsect1 id="environment"> - <title>ENVIRONMENT</title> - <para>The following environment variable affects the execution of the - allocation functions: - <variablelist> - <varlistentry> - <term><envar>MALLOC_CONF</envar></term> - - <listitem><para>If the environment variable - <envar>MALLOC_CONF</envar> is set, the characters it contains - will be interpreted as options.</para></listitem> - </varlistentry> - </variablelist> - </para> - </refsect1> - <refsect1 id="examples"> - <title>EXAMPLES</title> - <para>To dump core whenever a problem occurs: - <screen>ln -s 'abort:true' /etc/malloc.conf</screen> - </para> - <para>To specify in the source that only one arena should be automatically - created: - <programlisting language="C"><![CDATA[ -malloc_conf = "narenas:1";]]></programlisting></para> - </refsect1> - <refsect1 id="see_also"> - <title>SEE ALSO</title> - <para><citerefentry><refentrytitle>madvise</refentrytitle> - <manvolnum>2</manvolnum></citerefentry>, - <citerefentry><refentrytitle>mmap</refentrytitle> - <manvolnum>2</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sbrk</refentrytitle> - <manvolnum>2</manvolnum></citerefentry>, - <citerefentry><refentrytitle>utrace</refentrytitle> - <manvolnum>2</manvolnum></citerefentry>, - <citerefentry><refentrytitle>alloca</refentrytitle> - <manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>atexit</refentrytitle> - <manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>getpagesize</refentrytitle> - <manvolnum>3</manvolnum></citerefentry></para> - </refsect1> - <refsect1 id="standards"> - <title>STANDARDS</title> - <para>The <function>malloc()</function>, - <function>calloc()</function>, - <function>realloc()</function>, and - <function>free()</function> functions conform to ISO/IEC - 9899:1990 (<quote>ISO C90</quote>).</para> - - <para>The <function>posix_memalign()</function> function conforms - to IEEE Std 1003.1-2001 (<quote>POSIX.1</quote>).</para> - </refsect1> -</refentry> |