diff options
Diffstat (limited to 'deps/jemalloc/doc/jemalloc.xml.in')
| -rw-r--r-- | deps/jemalloc/doc/jemalloc.xml.in | 1899 |
1 files changed, 1258 insertions, 641 deletions
diff --git a/deps/jemalloc/doc/jemalloc.xml.in b/deps/jemalloc/doc/jemalloc.xml.in index 8fc774b18..1e12fd3a8 100644 --- a/deps/jemalloc/doc/jemalloc.xml.in +++ b/deps/jemalloc/doc/jemalloc.xml.in @@ -52,7 +52,7 @@ <title>LIBRARY</title> <para>This manual describes jemalloc @jemalloc_version@. More information can be found at the <ulink - url="http://www.canonware.com/jemalloc/">jemalloc website</ulink>.</para> + url="http://jemalloc.net/">jemalloc website</ulink>.</para> </refsect1> <refsynopsisdiv> <title>SYNOPSIS</title> @@ -180,20 +180,20 @@ <refsect2> <title>Standard API</title> - <para>The <function>malloc<parameter/></function> function allocates + <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<parameter/></function> function allocates + <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<parameter/></function> with an argument of + 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<parameter/></function> function + <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 @@ -201,7 +201,7 @@ <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<parameter/></function> function + <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 @@ -209,7 +209,7 @@ undefined if <parameter>size</parameter> is not an integral multiple of <parameter>alignment</parameter>.</para> - <para>The <function>realloc<parameter/></function> function changes the + <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 @@ -217,26 +217,26 @@ 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<parameter/></function> may move the memory allocation, + <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<parameter/></function> function behaves identically to - <function>malloc<parameter/></function> for the specified size.</para> + <function>realloc()</function> function behaves identically to + <function>malloc()</function> for the specified size.</para> - <para>The <function>free<parameter/></function> function causes the + <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<parameter/></function>, - <function>rallocx<parameter/></function>, - <function>xallocx<parameter/></function>, - <function>sallocx<parameter/></function>, - <function>dallocx<parameter/></function>, - <function>sdallocx<parameter/></function>, and - <function>nallocx<parameter/></function> functions all have a + <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 @@ -307,21 +307,19 @@ </variablelist> </para> - <para>The <function>mallocx<parameter/></function> function allocates at + <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>, or if request size - overflows due to size class and/or alignment constraints.</para> + <parameter>size</parameter> is <constant>0</constant>.</para> - <para>The <function>rallocx<parameter/></function> function resizes the + <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>, or if request size - overflows due to size class and/or alignment constraints.</para> + <parameter>size</parameter> is <constant>0</constant>.</para> - <para>The <function>xallocx<parameter/></function> function resizes the + <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 @@ -334,32 +332,32 @@ language="C">(<parameter>size</parameter> + <parameter>extra</parameter> > <constant>SIZE_T_MAX</constant>)</code>.</para> - <para>The <function>sallocx<parameter/></function> function returns the + <para>The <function>sallocx()</function> function returns the real size of the allocation at <parameter>ptr</parameter>.</para> - <para>The <function>dallocx<parameter/></function> function causes the + <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<parameter/></function> function is an - extension of <function>dallocx<parameter/></function> with a + <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<parameter/></function> or - <function>sallocx<parameter/></function>.</para> + <function>nallocx()</function> or + <function>sallocx()</function>.</para> - <para>The <function>nallocx<parameter/></function> function allocates no + <para>The <function>nallocx()</function> function allocates no memory, but it performs the same size computation as the - <function>mallocx<parameter/></function> function, and returns the real + <function>mallocx()</function> function, and returns the real size of the allocation that would result from the equivalent - <function>mallocx<parameter/></function> function call. Behavior is - undefined if <parameter>size</parameter> is <constant>0</constant>, or if - request size overflows due to size class and/or alignment - constraints.</para> + <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<parameter/></function> function provides a + <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 @@ -374,12 +372,12 @@ <parameter>newlen</parameter>; otherwise pass <constant>NULL</constant> and <constant>0</constant>.</para> - <para>The <function>mallctlnametomib<parameter/></function> function + <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 “Management Information Base” (MIB) that can be passed - repeatedly to <function>mallctlbymib<parameter/></function>. Upon - successful return from <function>mallctlnametomib<parameter/></function>, + 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 @@ -408,43 +406,47 @@ for (i = 0; i < nbins; i++) { mib[2] = i; len = sizeof(bin_size); - mallctlbymib(mib, miblen, &bin_size, &len, NULL, 0); + mallctlbymib(mib, miblen, (void *)&bin_size, &len, NULL, 0); /* Do something with bin_size... */ }]]></programlisting></para> - <para>The <function>malloc_stats_print<parameter/></function> function - writes human-readable 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<parameter/></function> if - <parameter>write_cb</parameter> is <constant>NULL</constant>. This - function can be called repeatedly. General information that never - changes during execution can be omitted by specifying "g" as a character + <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<parameter/></function> uses the - <function>mallctl*<parameter/></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, “m” and “a” can - be specified to omit merged arena and per arena statistics, respectively; - “b”, “l”, and “h” can be specified to - omit per size class statistics for bins, large objects, and huge objects, - respectively. Unrecognized characters are silently ignored. 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> + thread cache operations.</para> - <para>The <function>malloc_usable_size<parameter/></function> function + <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<parameter/></function> function is not a - mechanism for in-place <function>realloc<parameter/></function>; rather + <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<parameter/></function> should not be + by <function>malloc_usable_size()</function> should not be depended on, since such behavior is entirely implementation-dependent. </para> </refsect2> @@ -455,19 +457,20 @@ for (i = 0; i < nbins; i++) { 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 pointed to by the global variable - <varname>malloc_conf</varname>, the “name” of the file - referenced by the symbolic link named <filename - class="symlink">/etc/malloc.conf</filename>, and the value of the + <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<parameter/></function> is entered, so the declaration of + <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. <varname>malloc_conf</varname> is - a compile-time setting, whereas <filename - class="symlink">/etc/malloc.conf</filename> and <envar>MALLOC_CONF</envar> - can be safely set any time prior to program invocation.</para> + 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 @@ -509,33 +512,21 @@ for (i = 0; i < nbins; i++) { 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, unless - <option>--disable-tcache</option> is specified during configuration, this - allocator supports thread-specific caching for small and large objects, 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 equal-sized chunks, where the - chunk size is a power of two that is greater than the page size. Chunks - are always aligned to multiples of the chunk size. This alignment makes it - possible to find metadata for user objects very quickly.</para> - - <para>User objects are broken into three categories according to size: - small, large, and huge. Small and large objects are managed entirely by - arenas; huge objects are additionally aggregated in a single data structure - that is shared by all threads. Huge objects are typically used by - applications infrequently enough that this single data structure is not a - scalability issue.</para> - - <para>Each chunk that is managed by an arena tracks its contents as runs of - contiguous pages (unused, backing a set of small objects, or backing one - large object). The combination of chunk alignment and chunk page maps - makes it possible to determine all metadata regarding small and large - allocations in constant time.</para> - - <para>Small objects are managed in groups by page runs. Each run maintains + <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 @@ -543,11 +534,9 @@ for (i = 0; i < nbins; i++) { 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, large size classes are smaller - than the chunk size (see the <link - linkend="opt.lg_chunk"><mallctl>opt.lg_chunk</mallctl></link> option), and - huge size classes extend from the chunk size up to one size class less than - the full address space size.</para> + 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 @@ -555,30 +544,28 @@ for (i = 0; i < nbins; i++) { nearest multiple of the cacheline size, or specify cacheline alignment when allocating.</para> - <para>The <function>realloc<parameter/></function>, - <function>rallocx<parameter/></function>, and - <function>xallocx<parameter/></function> functions may resize allocations + <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<parameter/></function> API, the standard API does not + <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<parameter/></function> to grow e.g. a 9-byte allocation to + <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 - and huge allocations in place, as long as the pre-size and post-size are - both large or both huge. In such cases shrinkage always succeeds for large - size classes, but for huge size classes the chunk allocator must support - splitting (see <link - linkend="arena.i.chunk_hooks"><mallctl>arena.<i>.chunk_hooks</mallctl></link>). - Growth only succeeds if the trailing memory is currently available, and - additionally for huge size classes the chunk allocator must support - merging.</para> - - <para>Assuming 2 MiB chunks, 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> + 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> @@ -632,7 +619,7 @@ for (i = 0; i < nbins; i++) { <entry>[10 KiB, 12 KiB, 14 KiB]</entry> </row> <row> - <entry morerows="7">Large</entry> + <entry morerows="15">Large</entry> <entry>2 KiB</entry> <entry>[16 KiB]</entry> </row> @@ -662,12 +649,7 @@ for (i = 0; i < nbins; i++) { </row> <row> <entry>256 KiB</entry> - <entry>[1280 KiB, 1536 KiB, 1792 KiB]</entry> - </row> - <row> - <entry morerows="6">Huge</entry> - <entry>256 KiB</entry> - <entry>[2 MiB]</entry> + <entry>[1280 KiB, 1536 KiB, 1792 KiB, 2 MiB]</entry> </row> <row> <entry>512 KiB</entry> @@ -693,6 +675,14 @@ for (i = 0; i < nbins; i++) { <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> @@ -700,19 +690,32 @@ for (i = 0; i < nbins; i++) { <refsect1 id="mallctl_namespace"> <title>MALLCTL NAMESPACE</title> <para>The following names are defined in the namespace accessible via the - <function>mallctl*<parameter/></function> functions. Value types are - specified in parentheses, their readable/writable statuses are encoded as + <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>, - <literal><i></literal> equal to <link - linkend="arenas.narenas"><mallctl>arenas.narenas</mallctl></link> can be - used to access the summation of statistics from all arenas. Take special - note of the <link linkend="epoch"><mallctl>epoch</mallctl></link> mallctl, - which controls refreshing of cached dynamic statistics.</para> + 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"> @@ -731,11 +734,45 @@ for (i = 0; i < nbins; i++) { <literal>rw</literal> </term> <listitem><para>If a value is passed in, refresh the data from which - the <function>mallctl*<parameter/></function> functions report values, + 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> @@ -776,14 +813,15 @@ for (i = 0; i < nbins; i++) { during build configuration.</para></listitem> </varlistentry> - <varlistentry id="config.munmap"> + <varlistentry id="config.malloc_conf"> <term> - <mallctl>config.munmap</mallctl> - (<type>bool</type>) + <mallctl>config.malloc_conf</mallctl> + (<type>const char *</type>) <literal>r-</literal> </term> - <listitem><para><option>--enable-munmap</option> was specified during - build configuration.</para></listitem> + <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"> @@ -826,68 +864,94 @@ for (i = 0; i < nbins; i++) { build configuration.</para></listitem> </varlistentry> - <varlistentry id="config.tcache"> + + <varlistentry id="config.utrace"> <term> - <mallctl>config.tcache</mallctl> + <mallctl>config.utrace</mallctl> (<type>bool</type>) <literal>r-</literal> </term> - <listitem><para><option>--disable-tcache</option> was not specified - during build configuration.</para></listitem> + <listitem><para><option>--enable-utrace</option> was specified during + build configuration.</para></listitem> </varlistentry> - <varlistentry id="config.tls"> + <varlistentry id="config.xmalloc"> <term> - <mallctl>config.tls</mallctl> + <mallctl>config.xmalloc</mallctl> (<type>bool</type>) <literal>r-</literal> </term> - <listitem><para><option>--disable-tls</option> was not specified during + <listitem><para><option>--enable-xmalloc</option> was specified during build configuration.</para></listitem> </varlistentry> - <varlistentry id="config.utrace"> + <varlistentry id="opt.abort"> <term> - <mallctl>config.utrace</mallctl> + <mallctl>opt.abort</mallctl> (<type>bool</type>) <literal>r-</literal> </term> - <listitem><para><option>--enable-utrace</option> was specified during - build configuration.</para></listitem> + <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="config.valgrind"> + <varlistentry id="opt.abort_conf"> <term> - <mallctl>config.valgrind</mallctl> + <mallctl>opt.abort_conf</mallctl> (<type>bool</type>) <literal>r-</literal> </term> - <listitem><para><option>--enable-valgrind</option> was specified during - build configuration.</para></listitem> + <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="config.xmalloc"> + <varlistentry id="opt.metadata_thp"> <term> - <mallctl>config.xmalloc</mallctl> - (<type>bool</type>) + <mallctl>opt.metadata_thp</mallctl> + (<type>const char *</type>) <literal>r-</literal> </term> - <listitem><para><option>--enable-xmalloc</option> was specified during - build configuration.</para></listitem> + <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.abort"> + <varlistentry id="opt.retain"> <term> - <mallctl>opt.abort</mallctl> + <mallctl>opt.retain</mallctl> (<type>bool</type>) <literal>r-</literal> </term> - <listitem><para>Abort-on-warning enabled/disabled. If true, most - warnings 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. + <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> @@ -904,61 +968,136 @@ for (i = 0; i < nbins; i++) { settings are supported if <citerefentry><refentrytitle>sbrk</refentrytitle> <manvolnum>2</manvolnum></citerefentry> is supported by the operating - system: “disabled”, “primary”, and - “secondary”; otherwise only “disabled” is - supported. The default is “secondary” if + 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; “disabled” otherwise. + system; <quote>disabled</quote> otherwise. </para></listitem> </varlistentry> - <varlistentry id="opt.lg_chunk"> + <varlistentry id="opt.narenas"> <term> - <mallctl>opt.lg_chunk</mallctl> - (<type>size_t</type>) + <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>Virtual memory chunk size (log base 2). If a chunk - size outside the supported size range is specified, the size is - silently clipped to the minimum/maximum supported size. The default - chunk size is 2 MiB (2^21). + <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.narenas"> + <varlistentry id="opt.background_thread"> <term> - <mallctl>opt.narenas</mallctl> - (<type>size_t</type>) + <mallctl>opt.background_thread</mallctl> + (<type>const bool</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> + <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.lg_dirty_mult"> + <varlistentry id="opt.dirty_decay_ms"> <term> - <mallctl>opt.lg_dirty_mult</mallctl> + <mallctl>opt.dirty_decay_ms</mallctl> (<type>ssize_t</type>) <literal>r-</literal> </term> - <listitem><para>Per-arena minimum ratio (log base 2) of active to dirty - pages. Some dirty unused pages may be allowed to accumulate, within - the limit set by the ratio (or one chunk worth of dirty pages, - whichever is greater), before informing the kernel about some of those - pages via <citerefentry><refentrytitle>madvise</refentrytitle> - <manvolnum>2</manvolnum></citerefentry> or a similar system call. This - provides the kernel with sufficient information to recycle dirty pages - if physical memory becomes scarce and the pages remain unused. The - default minimum ratio is 8:1 (2^3:1); an option value of -1 will - disable dirty page purging. See <link - linkend="arenas.lg_dirty_mult"><mallctl>arenas.lg_dirty_mult</mallctl></link> + <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.lg_dirty_mult"><mallctl>arena.<i>.lg_dirty_mult</mallctl></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> @@ -966,82 +1105,61 @@ for (i = 0; i < nbins; i++) { <literal>r-</literal> </term> <listitem><para>Enable/disable statistics printing at exit. If - enabled, the <function>malloc_stats_print<parameter/></function> + enabled, the <function>malloc_stats_print()</function> function is called at program exit via an <citerefentry><refentrytitle>atexit</refentrytitle> - <manvolnum>3</manvolnum></citerefentry> function. If + <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<parameter/></function> may + functions. Furthermore, <function>atexit()</function> may allocate memory during application initialization and then deadlock internally when jemalloc in turn calls - <function>atexit<parameter/></function>, so this option is not - univerally usable (though the application can register its own - <function>atexit<parameter/></function> function with equivalent + <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.junk"> + <varlistentry id="opt.stats_print_opts"> <term> - <mallctl>opt.junk</mallctl> + <mallctl>opt.stats_print_opts</mallctl> (<type>const char *</type>) <literal>r-</literal> - [<option>--enable-fill</option>] </term> - <listitem><para>Junk filling. If set to "alloc", each byte of - uninitialized allocated memory will be initialized to - <literal>0xa5</literal>. If set to "free", all deallocated memory will - be initialized to <literal>0x5a</literal>. If set to "true", both - allocated and deallocated memory will be initialized, and if set to - "false", junk filling be disabled entirely. This is intended for - debugging and will impact performance negatively. This option is - "false" by default unless <option>--enable-debug</option> is specified - during configuration, in which case it is "true" by default unless - running inside <ulink - url="http://valgrind.org/">Valgrind</ulink>.</para></listitem> + <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.quarantine"> - <term> - <mallctl>opt.quarantine</mallctl> - (<type>size_t</type>) - <literal>r-</literal> - [<option>--enable-fill</option>] - </term> - <listitem><para>Per thread quarantine size in bytes. If non-zero, each - thread maintains a FIFO object quarantine that stores up to the - specified number of bytes of memory. The quarantined memory is not - freed until it is released from quarantine, though it is immediately - junk-filled if the <link - linkend="opt.junk"><mallctl>opt.junk</mallctl></link> option is - enabled. This feature is of particular use in combination with <ulink - url="http://valgrind.org/">Valgrind</ulink>, which can detect attempts - to access quarantined objects. This is intended for debugging and will - impact performance negatively. The default quarantine size is 0 unless - running inside Valgrind, in which case the default is 16 - MiB.</para></listitem> - </varlistentry> - - <varlistentry id="opt.redzone"> + <varlistentry id="opt.junk"> <term> - <mallctl>opt.redzone</mallctl> - (<type>bool</type>) + <mallctl>opt.junk</mallctl> + (<type>const char *</type>) <literal>r-</literal> [<option>--enable-fill</option>] </term> - <listitem><para>Redzones enabled/disabled. If enabled, small - allocations have redzones before and after them. Furthermore, if the - <link linkend="opt.junk"><mallctl>opt.junk</mallctl></link> option is - enabled, the redzones are checked for corruption during deallocation. - However, the primary intended purpose of this feature is to be used in - combination with <ulink url="http://valgrind.org/">Valgrind</ulink>, - which needs redzones in order to do effective buffer overflow/underflow - detection. This option is intended for debugging and will impact - performance negatively. This option is disabled by - default unless running inside Valgrind.</para></listitem> + <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"> @@ -1054,8 +1172,8 @@ for (i = 0; i < nbins; i++) { <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<parameter/></function> and - <function>rallocx<parameter/></function> calls do not zero memory that + <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> @@ -1099,7 +1217,6 @@ malloc_conf = "xmalloc:true";]]></programlisting> <mallctl>opt.tcache</mallctl> (<type>bool</type>) <literal>r-</literal> - [<option>--enable-tcache</option>] </term> <listitem><para>Thread-specific caching (tcache) enabled/disabled. When there are multiple threads, each thread uses a tcache for objects up to @@ -1108,9 +1225,7 @@ malloc_conf = "xmalloc:true";]]></programlisting> 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 unless running inside <ulink - url="http://valgrind.org/">Valgrind</ulink>, in which case it is - forcefully disabled.</para></listitem> + default.</para></listitem> </varlistentry> <varlistentry id="opt.lg_tcache_max"> @@ -1118,7 +1233,6 @@ malloc_conf = "xmalloc:true";]]></programlisting> <mallctl>opt.lg_tcache_max</mallctl> (<type>size_t</type>) <literal>r-</literal> - [<option>--enable-tcache</option>] </term> <listitem><para>Maximum size class (log base 2) to cache in the thread-specific cache (tcache). At a minimum, all small size classes @@ -1126,6 +1240,28 @@ malloc_conf = "xmalloc:true";]]></programlisting> 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> @@ -1150,7 +1286,8 @@ malloc_conf = "xmalloc:true";]]></programlisting> 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>.</para></listitem> + 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"> @@ -1277,11 +1414,11 @@ malloc_conf = "xmalloc:true";]]></programlisting> <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<parameter/></function> may allocate + option. Note that <function>atexit()</function> may allocate memory during application initialization and then deadlock internally - when jemalloc in turn calls <function>atexit<parameter/></function>, so - this option is not univerally usable (though the application can - register its own <function>atexit<parameter/></function> function with + 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> @@ -1311,7 +1448,7 @@ malloc_conf = "xmalloc:true";]]></programlisting> <listitem><para>Get or set the arena associated with the calling thread. If the specified arena was not initialized beforehand (see the <link - linkend="arenas.initialized"><mallctl>arenas.initialized</mallctl></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> @@ -1340,7 +1477,7 @@ malloc_conf = "xmalloc:true";]]></programlisting> <link linkend="thread.allocated"><mallctl>thread.allocated</mallctl></link> mallctl. This is useful for avoiding the overhead of repeated - <function>mallctl*<parameter/></function> calls.</para></listitem> + <function>mallctl*()</function> calls.</para></listitem> </varlistentry> <varlistentry id="thread.deallocated"> @@ -1367,7 +1504,7 @@ malloc_conf = "xmalloc:true";]]></programlisting> <link linkend="thread.deallocated"><mallctl>thread.deallocated</mallctl></link> mallctl. This is useful for avoiding the overhead of repeated - <function>mallctl*<parameter/></function> calls.</para></listitem> + <function>mallctl*()</function> calls.</para></listitem> </varlistentry> <varlistentry id="thread.tcache.enabled"> @@ -1375,7 +1512,6 @@ malloc_conf = "xmalloc:true";]]></programlisting> <mallctl>thread.tcache.enabled</mallctl> (<type>bool</type>) <literal>rw</literal> - [<option>--enable-tcache</option>] </term> <listitem><para>Enable/disable calling thread's tcache. The tcache is implicitly flushed as a side effect of becoming @@ -1389,7 +1525,6 @@ malloc_conf = "xmalloc:true";]]></programlisting> <mallctl>thread.tcache.flush</mallctl> (<type>void</type>) <literal>--</literal> - [<option>--enable-tcache</option>] </term> <listitem><para>Flush calling thread's thread-specific cache (tcache). This interface releases all cached objects and internal data structures @@ -1418,8 +1553,8 @@ malloc_conf = "xmalloc:true";]]></programlisting> 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 nil-terminated and comprised only of characters in the - sets recognized + 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> @@ -1445,7 +1580,6 @@ malloc_conf = "xmalloc:true";]]></programlisting> <mallctl>tcache.create</mallctl> (<type>unsigned</type>) <literal>r-</literal> - [<option>--enable-tcache</option>] </term> <listitem><para>Create an explicit thread-specific cache (tcache) and return an identifier that can be passed to the <link @@ -1462,12 +1596,11 @@ malloc_conf = "xmalloc:true";]]></programlisting> <mallctl>tcache.flush</mallctl> (<type>unsigned</type>) <literal>-w</literal> - [<option>--enable-tcache</option>] </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 be discarded. + except that the tcache will never be automatically discarded. </para></listitem> </varlistentry> @@ -1476,25 +1609,86 @@ malloc_conf = "xmalloc:true";]]></programlisting> <mallctl>tcache.destroy</mallctl> (<type>unsigned</type>) <literal>-w</literal> - [<option>--enable-tcache</option>] </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 unused dirty pages for arena <i>, or for - all arenas if <i> equals <link - linkend="arenas.narenas"><mallctl>arenas.narenas</mallctl></link>. + <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> @@ -1503,71 +1697,109 @@ malloc_conf = "xmalloc:true";]]></programlisting> </term> <listitem><para>Set the precedence of dss allocation as related to mmap allocation for arena <i>, or for all arenas if <i> equals - <link - linkend="arenas.narenas"><mallctl>arenas.narenas</mallctl></link>. See - <link linkend="opt.dss"><mallctl>opt.dss</mallctl></link> for supported + <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.lg_dirty_mult"> + <varlistentry id="arena.i.dirty_decay_ms"> <term> - <mallctl>arena.<i>.lg_dirty_mult</mallctl> + <mallctl>arena.<i>.dirty_decay_ms</mallctl> (<type>ssize_t</type>) <literal>rw</literal> </term> - <listitem><para>Current per-arena minimum ratio (log base 2) of active - to dirty pages for arena <i>. Each time this interface is set and - the ratio is increased, pages are synchronously purged as necessary to - impose the new ratio. See <link - linkend="opt.lg_dirty_mult"><mallctl>opt.lg_dirty_mult</mallctl></link> + <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.chunk_hooks"> + <varlistentry id="arena.i.muzzy_decay_ms"> <term> - <mallctl>arena.<i>.chunk_hooks</mallctl> - (<type>chunk_hooks_t</type>) + <mallctl>arena.<i>.muzzy_decay_ms</mallctl> + (<type>ssize_t</type>) <literal>rw</literal> </term> - <listitem><para>Get or set the chunk management hook functions for arena - <i>. The functions must be capable of operating on all extant - chunks associated with arena <i>, usually by passing unknown - chunks to the replaced functions. In practice, it is feasible to - control allocation for arenas created via <link - linkend="arenas.extend"><mallctl>arenas.extend</mallctl></link> such - that all chunks originate from an application-supplied chunk allocator - (by setting custom chunk hook functions just after arena creation), but - the automatically created arenas may have already created chunks prior - to the application having an opportunity to take over chunk + <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 struct { - chunk_alloc_t *alloc; - chunk_dalloc_t *dalloc; - chunk_commit_t *commit; - chunk_decommit_t *decommit; - chunk_purge_t *purge; - chunk_split_t *split; - chunk_merge_t *merge; -} chunk_hooks_t;]]></programlisting> - <para>The <type>chunk_hooks_t</type> structure comprises function +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 chunk lifetime, which starts off with allocation of + 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 chunks for - later reuse. Cleanup attempts cascade from deallocation to decommit to - purging, which gives the chunk management functions opportunities to - reject the most permanent cleanup operations in favor of less permanent - (and often less costly) operations. The chunk splitting and merging - operations can also be opted out of, but this is mainly intended to - support platforms on which virtual memory mappings provided by the - operating system kernel do not automatically coalesce and split, e.g. - Windows.</para> + 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>(chunk_alloc_t)</function></funcdef> - <paramdef>void *<parameter>chunk</parameter></paramdef> + <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> @@ -1575,62 +1807,83 @@ typedef struct { <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> </funcprototype></funcsynopsis> <literallayout></literallayout> - <para>A chunk allocation function conforms to the - <type>chunk_alloc_t</type> type and upon success returns a pointer to + <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 chunk's base address is a - multiple of <parameter>alignment</parameter>, as well as setting - <parameter>*zero</parameter> to indicate whether the chunk is zeroed and - <parameter>*commit</parameter> to indicate whether the chunk is + <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 chunk + <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 chunk size. Zeroing is mandatory if + 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>chunk</parameter> is not <constant>NULL</constant>, the - returned pointer must be <parameter>chunk</parameter> on success or + 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 chunk allocation function makes the arena's <link + 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>(chunk_dalloc_t)</function></funcdef> - <paramdef>void *<parameter>chunk</parameter></paramdef> + <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> - A chunk deallocation function conforms to the - <type>chunk_dalloc_t</type> type and deallocates a - <parameter>chunk</parameter> of given <parameter>size</parameter> with + 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 chunk + 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 bool <function>(chunk_commit_t)</function></funcdef> - <paramdef>void *<parameter>chunk</parameter></paramdef> + <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>A chunk commit function conforms to the - <type>chunk_commit_t</type> type and commits zeroed physical memory to - back pages within a <parameter>chunk</parameter> of given + <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. @@ -1641,46 +1894,56 @@ typedef struct { physical memory to satisfy the request.</para> <funcsynopsis><funcprototype> - <funcdef>typedef bool <function>(chunk_decommit_t)</function></funcdef> - <paramdef>void *<parameter>chunk</parameter></paramdef> + <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>A chunk decommit function conforms to the - <type>chunk_decommit_t</type> type and decommits any physical memory - that is backing pages within a <parameter>chunk</parameter> of given - <parameter>size</parameter> at <parameter>offset</parameter> bytes, - extending for <parameter>length</parameter> on behalf of arena + <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 chunk commit function before + 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>(chunk_purge_t)</function></funcdef> - <paramdef>void *<parameter>chunk</parameter></paramdef> - <paramdef>size_t<parameter>size</parameter></paramdef> + <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>A chunk purge function conforms to the <type>chunk_purge_t</type> - type and optionally discards physical pages within the virtual memory - mapping associated with <parameter>chunk</parameter> of given - <parameter>size</parameter> at <parameter>offset</parameter> bytes, - extending for <parameter>length</parameter> on behalf of arena - <parameter>arena_ind</parameter>, returning false if pages within the - purged virtual memory range will be zero-filled the next time they are - accessed.</para> + <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>(chunk_split_t)</function></funcdef> - <paramdef>void *<parameter>chunk</parameter></paramdef> + <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> @@ -1688,35 +1951,36 @@ typedef struct { <paramdef>unsigned <parameter>arena_ind</parameter></paramdef> </funcprototype></funcsynopsis> <literallayout></literallayout> - <para>A chunk split function conforms to the <type>chunk_split_t</type> - type and optionally splits <parameter>chunk</parameter> of given - <parameter>size</parameter> into two adjacent chunks, the first of - <parameter>size_a</parameter> bytes, and the second of - <parameter>size_b</parameter> bytes, operating on + <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 chunk + 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>(chunk_merge_t)</function></funcdef> - <paramdef>void *<parameter>chunk_a</parameter></paramdef> + <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>chunk_b</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>A chunk merge function conforms to the <type>chunk_merge_t</type> - type and optionally merges adjacent chunks, - <parameter>chunk_a</parameter> of given <parameter>size_a</parameter> - and <parameter>chunk_b</parameter> of given - <parameter>size_b</parameter> into one contiguous chunk, operating on + <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 chunks + 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> @@ -1731,29 +1995,35 @@ typedef struct { <listitem><para>Current limit on number of arenas.</para></listitem> </varlistentry> - <varlistentry id="arenas.initialized"> + <varlistentry id="arenas.dirty_decay_ms"> <term> - <mallctl>arenas.initialized</mallctl> - (<type>bool *</type>) - <literal>r-</literal> + <mallctl>arenas.dirty_decay_ms</mallctl> + (<type>ssize_t</type>) + <literal>rw</literal> </term> - <listitem><para>An array of <link - linkend="arenas.narenas"><mallctl>arenas.narenas</mallctl></link> - booleans. Each boolean indicates whether the corresponding arena is - initialized.</para></listitem> + <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.lg_dirty_mult"> + <varlistentry id="arenas.muzzy_decay_ms"> <term> - <mallctl>arenas.lg_dirty_mult</mallctl> + <mallctl>arenas.muzzy_decay_ms</mallctl> (<type>ssize_t</type>) <literal>rw</literal> </term> - <listitem><para>Current default per-arena minimum ratio (log base 2) of - active to dirty pages, used to initialize <link - linkend="arena.i.lg_dirty_mult"><mallctl>arena.<i>.lg_dirty_mult</mallctl></link> + <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.lg_dirty_mult"><mallctl>opt.lg_dirty_mult</mallctl></link> + linkend="opt.muzzy_decay_ms"><mallctl>opt.muzzy_decay_ms</mallctl></link> for additional information.</para></listitem> </varlistentry> @@ -1780,7 +2050,6 @@ typedef struct { <mallctl>arenas.tcache_max</mallctl> (<type>size_t</type>) <literal>r-</literal> - [<option>--enable-tcache</option>] </term> <listitem><para>Maximum thread-cached size class.</para></listitem> </varlistentry> @@ -1799,7 +2068,6 @@ typedef struct { <mallctl>arenas.nhbins</mallctl> (<type>unsigned</type>) <literal>r-</literal> - [<option>--enable-tcache</option>] </term> <listitem><para>Total number of thread cache bin size classes.</para></listitem> @@ -1820,30 +2088,30 @@ typedef struct { (<type>uint32_t</type>) <literal>r-</literal> </term> - <listitem><para>Number of regions per page run.</para></listitem> + <listitem><para>Number of regions per slab.</para></listitem> </varlistentry> - <varlistentry id="arenas.bin.i.run_size"> + <varlistentry id="arenas.bin.i.slab_size"> <term> - <mallctl>arenas.bin.<i>.run_size</mallctl> + <mallctl>arenas.bin.<i>.slab_size</mallctl> (<type>size_t</type>) <literal>r-</literal> </term> - <listitem><para>Number of bytes per page run.</para></listitem> + <listitem><para>Number of bytes per slab.</para></listitem> </varlistentry> - <varlistentry id="arenas.nlruns"> + <varlistentry id="arenas.nlextents"> <term> - <mallctl>arenas.nlruns</mallctl> + <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.lrun.i.size"> + <varlistentry id="arenas.lextent.i.size"> <term> - <mallctl>arenas.lrun.<i>.size</mallctl> + <mallctl>arenas.lextent.<i>.size</mallctl> (<type>size_t</type>) <literal>r-</literal> </term> @@ -1851,33 +2119,24 @@ typedef struct { class.</para></listitem> </varlistentry> - <varlistentry id="arenas.nhchunks"> - <term> - <mallctl>arenas.nhchunks</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> - </term> - <listitem><para>Total number of huge size classes.</para></listitem> - </varlistentry> - - <varlistentry id="arenas.hchunk.i.size"> + <varlistentry id="arenas.create"> <term> - <mallctl>arenas.hchunk.<i>.size</mallctl> - (<type>size_t</type>) - <literal>r-</literal> + <mallctl>arenas.create</mallctl> + (<type>unsigned</type>, <type>extent_hooks_t *</type>) + <literal>rw</literal> </term> - <listitem><para>Maximum size supported by this huge size - class.</para></listitem> + <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.extend"> + <varlistentry id="arenas.lookup"> <term> - <mallctl>arenas.extend</mallctl> - (<type>unsigned</type>) - <literal>r-</literal> + <mallctl>arenas.lookup</mallctl> + (<type>unsigned</type>, <type>void*</type>) + <literal>rw</literal> </term> - <listitem><para>Extend the array of arenas by appending a new arena, - and returning the new arena index.</para></listitem> + <listitem><para>Index of the arena to which an allocation belongs to.</para></listitem> </varlistentry> <varlistentry id="prof.thread_active_init"> @@ -1976,30 +2235,12 @@ typedef struct { [<option>--enable-prof</option>] </term> <listitem><para>Average number of bytes allocated between - inverval-based profile dumps. See the + 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.cactive"> - <term> - <mallctl>stats.cactive</mallctl> - (<type>size_t *</type>) - <literal>r-</literal> - [<option>--enable-stats</option>] - </term> - <listitem><para>Pointer to a counter that contains an approximate count - of the current number of bytes in active pages. The estimate may be - high, but never low, because each arena rounds up when computing its - contribution to the counter. Note that the <link - linkend="epoch"><mallctl>epoch</mallctl></link> mallctl has no bearing - on this counter. Furthermore, counter consistency is maintained via - atomic operations, so it is necessary to use an atomic operation in - order to guarantee a consistent read when dereferencing the pointer. - </para></listitem> - </varlistentry> - <varlistentry id="stats.allocated"> <term> <mallctl>stats.allocated</mallctl> @@ -2023,7 +2264,9 @@ typedef struct { 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>, nor pages + <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> @@ -2035,11 +2278,28 @@ typedef struct { [<option>--enable-stats</option>] </term> <listitem><para>Total number of bytes dedicated to metadata, which - comprise base allocations used for bootstrap-sensitive internal - allocator data structures, arena chunk headers (see <link - linkend="stats.arenas.i.metadata.mapped"><mallctl>stats.arenas.<i>.metadata.mapped</mallctl></link>), + 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.metadata.allocated"><mallctl>stats.arenas.<i>.metadata.allocated</mallctl></link>).</para></listitem> + 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"> @@ -2066,15 +2326,155 @@ typedef struct { <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Total number of bytes in active chunks mapped by the - allocator. This is a multiple of the chunk size, and is larger than - <link linkend="stats.active"><mallctl>stats.active</mallctl></link>. - This does not include inactive chunks, even those that contain unused - dirty pages, which means that there is no strict ordering between this - and <link + <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> @@ -2089,15 +2489,29 @@ typedef struct { </para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.lg_dirty_mult"> + <varlistentry id="stats.arenas.i.dirty_decay_ms"> <term> - <mallctl>stats.arenas.<i>.lg_dirty_mult</mallctl> + <mallctl>stats.arenas.<i>.dirty_decay_ms</mallctl> (<type>ssize_t</type>) <literal>r-</literal> </term> - <listitem><para>Minimum ratio (log base 2) of active to dirty pages. - See <link - linkend="opt.lg_dirty_mult"><mallctl>opt.lg_dirty_mult</mallctl></link> + <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> @@ -2111,13 +2525,25 @@ typedef struct { 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 runs.</para></listitem> + <listitem><para>Number of pages in active extents.</para></listitem> </varlistentry> <varlistentry id="stats.arenas.i.pdirty"> @@ -2126,10 +2552,23 @@ typedef struct { (<type>size_t</type>) <literal>r-</literal> </term> - <listitem><para>Number of pages within unused runs that are potentially - dirty, and for which <function>madvise<parameter>...</parameter> - <parameter><constant>MADV_DONTNEED</constant></parameter></function> or - similar has not been called.</para></listitem> + <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"> @@ -2142,20 +2581,33 @@ typedef struct { <listitem><para>Number of mapped bytes.</para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.metadata.mapped"> + <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>.metadata.mapped</mallctl> + <mallctl>stats.arenas.<i>.base</mallctl> (<type>size_t</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Number of mapped bytes in arena chunk headers, which - track the states of the non-metadata pages.</para></listitem> + <listitem><para> + Number of bytes dedicated to bootstrap-sensitive allocator metadata + structures.</para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.metadata.allocated"> + <varlistentry id="stats.arenas.i.internal"> <term> - <mallctl>stats.arenas.<i>.metadata.allocated</mallctl> + <mallctl>stats.arenas.<i>.internal</mallctl> (<type>size_t</type>) <literal>r-</literal> [<option>--enable-stats</option>] @@ -2163,180 +2615,199 @@ typedef struct { <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. This statistic is reported separately from <link - linkend="stats.metadata"><mallctl>stats.metadata</mallctl></link> and - <link - linkend="stats.arenas.i.metadata.mapped"><mallctl>stats.arenas.<i>.metadata.mapped</mallctl></link> - because it overlaps with e.g. the <link - linkend="stats.allocated"><mallctl>stats.allocated</mallctl></link> and - <link linkend="stats.active"><mallctl>stats.active</mallctl></link> - statistics, whereas the other metadata statistics do - not.</para></listitem> + profiles.</para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.npurge"> + <varlistentry id="stats.arenas.i.metadata_thp"> <term> - <mallctl>stats.arenas.<i>.npurge</mallctl> - (<type>uint64_t</type>) + <mallctl>stats.arenas.<i>.metadata_thp</mallctl> + (<type>size_t</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Number of dirty page purge sweeps performed. - </para></listitem> + <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.nmadvise"> + <varlistentry id="stats.arenas.i.resident"> <term> - <mallctl>stats.arenas.<i>.nmadvise</mallctl> - (<type>uint64_t</type>) + <mallctl>stats.arenas.<i>.resident</mallctl> + (<type>size_t</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Number of <function>madvise<parameter>...</parameter> - <parameter><constant>MADV_DONTNEED</constant></parameter></function> or - similar calls made to purge dirty pages.</para></listitem> + <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.purged"> + <varlistentry id="stats.arenas.i.dirty_npurge"> <term> - <mallctl>stats.arenas.<i>.purged</mallctl> + <mallctl>stats.arenas.<i>.dirty_npurge</mallctl> (<type>uint64_t</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Number of pages purged.</para></listitem> + <listitem><para>Number of dirty page purge sweeps performed. + </para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.small.allocated"> + <varlistentry id="stats.arenas.i.dirty_nmadvise"> <term> - <mallctl>stats.arenas.<i>.small.allocated</mallctl> - (<type>size_t</type>) + <mallctl>stats.arenas.<i>.dirty_nmadvise</mallctl> + (<type>uint64_t</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Number of bytes currently allocated by small objects. - </para></listitem> + <listitem><para>Number of <function>madvise()</function> or similar + calls made to purge dirty pages.</para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.small.nmalloc"> + <varlistentry id="stats.arenas.i.dirty_purged"> <term> - <mallctl>stats.arenas.<i>.small.nmalloc</mallctl> + <mallctl>stats.arenas.<i>.dirty_purged</mallctl> (<type>uint64_t</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Cumulative number of allocation requests served by - small bins.</para></listitem> + <listitem><para>Number of dirty pages purged.</para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.small.ndalloc"> + <varlistentry id="stats.arenas.i.muzzy_npurge"> <term> - <mallctl>stats.arenas.<i>.small.ndalloc</mallctl> + <mallctl>stats.arenas.<i>.muzzy_npurge</mallctl> (<type>uint64_t</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Cumulative number of small objects returned to bins. + <listitem><para>Number of muzzy page purge sweeps performed. </para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.small.nrequests"> + <varlistentry id="stats.arenas.i.muzzy_nmadvise"> <term> - <mallctl>stats.arenas.<i>.small.nrequests</mallctl> + <mallctl>stats.arenas.<i>.muzzy_nmadvise</mallctl> (<type>uint64_t</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Cumulative number of small allocation requests. - </para></listitem> + <listitem><para>Number of <function>madvise()</function> or similar + calls made to purge muzzy pages.</para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.large.allocated"> + <varlistentry id="stats.arenas.i.muzzy_purged"> <term> - <mallctl>stats.arenas.<i>.large.allocated</mallctl> + <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 large objects. + <listitem><para>Number of bytes currently allocated by small objects. </para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.large.nmalloc"> + <varlistentry id="stats.arenas.i.small.nmalloc"> <term> - <mallctl>stats.arenas.<i>.large.nmalloc</mallctl> + <mallctl>stats.arenas.<i>.small.nmalloc</mallctl> (<type>uint64_t</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Cumulative number of large allocation requests served - directly by the arena.</para></listitem> + <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.large.ndalloc"> + <varlistentry id="stats.arenas.i.small.ndalloc"> <term> - <mallctl>stats.arenas.<i>.large.ndalloc</mallctl> + <mallctl>stats.arenas.<i>.small.ndalloc</mallctl> (<type>uint64_t</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Cumulative number of large deallocation requests served - directly by the arena.</para></listitem> + <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.large.nrequests"> + <varlistentry id="stats.arenas.i.small.nrequests"> <term> - <mallctl>stats.arenas.<i>.large.nrequests</mallctl> + <mallctl>stats.arenas.<i>.small.nrequests</mallctl> (<type>uint64_t</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Cumulative number of large allocation requests. - </para></listitem> + <listitem><para>Cumulative number of allocation requests satisfied by + all bin size classes.</para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.huge.allocated"> + <varlistentry id="stats.arenas.i.large.allocated"> <term> - <mallctl>stats.arenas.<i>.huge.allocated</mallctl> + <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 huge objects. + <listitem><para>Number of bytes currently allocated by large objects. </para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.huge.nmalloc"> + <varlistentry id="stats.arenas.i.large.nmalloc"> <term> - <mallctl>stats.arenas.<i>.huge.nmalloc</mallctl> + <mallctl>stats.arenas.<i>.large.nmalloc</mallctl> (<type>uint64_t</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Cumulative number of huge allocation requests served - directly by the arena.</para></listitem> + <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.huge.ndalloc"> + <varlistentry id="stats.arenas.i.large.ndalloc"> <term> - <mallctl>stats.arenas.<i>.huge.ndalloc</mallctl> + <mallctl>stats.arenas.<i>.large.ndalloc</mallctl> (<type>uint64_t</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Cumulative number of huge deallocation requests served - directly by the arena.</para></listitem> + <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.huge.nrequests"> + <varlistentry id="stats.arenas.i.large.nrequests"> <term> - <mallctl>stats.arenas.<i>.huge.nrequests</mallctl> + <mallctl>stats.arenas.<i>.large.nrequests</mallctl> (<type>uint64_t</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Cumulative number of huge allocation requests. - </para></listitem> + <listitem><para>Cumulative number of allocation requests satisfied by + all large size classes.</para></listitem> </varlistentry> <varlistentry id="stats.arenas.i.bins.j.nmalloc"> @@ -2346,8 +2817,11 @@ typedef struct { <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Cumulative number of allocations served by bin. - </para></listitem> + <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"> @@ -2357,8 +2831,11 @@ typedef struct { <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Cumulative number of allocations returned to bin. - </para></listitem> + <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"> @@ -2368,8 +2845,8 @@ typedef struct { <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Cumulative number of allocation - requests.</para></listitem> + <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"> @@ -2388,7 +2865,6 @@ typedef struct { <mallctl>stats.arenas.<i>.bins.<j>.nfills</mallctl> (<type>uint64_t</type>) <literal>r-</literal> - [<option>--enable-stats</option> <option>--enable-tcache</option>] </term> <listitem><para>Cumulative number of tcache fills.</para></listitem> </varlistentry> @@ -2398,131 +2874,273 @@ typedef struct { <mallctl>stats.arenas.<i>.bins.<j>.nflushes</mallctl> (<type>uint64_t</type>) <literal>r-</literal> - [<option>--enable-stats</option> <option>--enable-tcache</option>] </term> <listitem><para>Cumulative number of tcache flushes.</para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.bins.j.nruns"> + <varlistentry id="stats.arenas.i.bins.j.nslabs"> <term> - <mallctl>stats.arenas.<i>.bins.<j>.nruns</mallctl> + <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 runs created.</para></listitem> + <listitem><para>Cumulative number of slabs created.</para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.bins.j.nreruns"> + <varlistentry id="stats.arenas.i.bins.j.nreslabs"> <term> - <mallctl>stats.arenas.<i>.bins.<j>.nreruns</mallctl> + <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 run from which + <listitem><para>Cumulative number of times the current slab from which to allocate changed.</para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.bins.j.curruns"> + <varlistentry id="stats.arenas.i.bins.j.curslabs"> <term> - <mallctl>stats.arenas.<i>.bins.<j>.curruns</mallctl> + <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 runs.</para></listitem> + <listitem><para>Current number of slabs.</para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.lruns.j.nmalloc"> + <varlistentry id="stats.arenas.i.bins.mutex"> <term> - <mallctl>stats.arenas.<i>.lruns.<j>.nmalloc</mallctl> + <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 allocation requests for this size - class served directly by the arena.</para></listitem> + <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.lruns.j.ndalloc"> + <varlistentry id="stats.arenas.i.lextents.j.ndalloc"> <term> - <mallctl>stats.arenas.<i>.lruns.<j>.ndalloc</mallctl> + <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 deallocation requests for this - size class served directly by the arena.</para></listitem> + <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.lruns.j.nrequests"> + <varlistentry id="stats.arenas.i.lextents.j.nrequests"> <term> - <mallctl>stats.arenas.<i>.lruns.<j>.nrequests</mallctl> + <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 for this size - class.</para></listitem> + <listitem><para>Cumulative number of allocation requests satisfied by + large extents of the corresponding size class.</para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.lruns.j.curruns"> + <varlistentry id="stats.arenas.i.lextents.j.curlextents"> <term> - <mallctl>stats.arenas.<i>.lruns.<j>.curruns</mallctl> + <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 runs for this size class. + <listitem><para>Current number of large allocations for this size class. </para></listitem> </varlistentry> - <varlistentry id="stats.arenas.i.hchunks.j.nmalloc"> + <varlistentry id="stats.arenas.i.mutexes.large"> <term> - <mallctl>stats.arenas.<i>.hchunks.<j>.nmalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> + <mallctl>stats.arenas.<i>.mutexes.large.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Cumulative number of allocation requests for this size - class served directly by the arena.</para></listitem> + <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.hchunks.j.ndalloc"> + <varlistentry id="stats.arenas.i.mutexes.extent_avail"> <term> - <mallctl>stats.arenas.<i>.hchunks.<j>.ndalloc</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> + <mallctl>stats.arenas.<i>.mutexes.extent_avail.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Cumulative number of deallocation requests for this - size class served directly by the arena.</para></listitem> + <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.hchunks.j.nrequests"> + <varlistentry id="stats.arenas.i.mutexes.extents_dirty"> <term> - <mallctl>stats.arenas.<i>.hchunks.<j>.nrequests</mallctl> - (<type>uint64_t</type>) - <literal>r-</literal> + <mallctl>stats.arenas.<i>.mutexes.extents_dirty.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Cumulative number of allocation requests for this size - class.</para></listitem> + <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.hchunks.j.curhchunks"> + <varlistentry id="stats.arenas.i.mutexes.extents_muzzy"> <term> - <mallctl>stats.arenas.<i>.hchunks.<j>.curhchunks</mallctl> - (<type>size_t</type>) - <literal>r-</literal> + <mallctl>stats.arenas.<i>.mutexes.extents_muzzy.{counter}</mallctl> + (<type>counter specific type</type>) <literal>r-</literal> [<option>--enable-stats</option>] </term> - <listitem><para>Current number of huge allocations for this size class. - </para></listitem> + <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 @@ -2532,7 +3150,7 @@ typedef struct { of run-time assertions that catch application errors such as double-free, write-after-free, etc.</para> - <para>Programs often accidentally depend on “uninitialized” + <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 @@ -2544,9 +3162,7 @@ typedef struct { <para>This implementation does not provide much detail about the problems it detects, because the performance impact for storing such information - would be prohibitive. However, jemalloc does integrate with the most - excellent <ulink url="http://valgrind.org/">Valgrind</ulink> tool if the - <option>--enable-valgrind</option> configuration option is enabled.</para> + would be prohibitive.</para> </refsect1> <refsect1 id="diagnostic_messages"> <title>DIAGNOSTIC MESSAGES</title> @@ -2561,29 +3177,29 @@ typedef struct { 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<parameter/></function> takes the + <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<parameter/></function>, followed by a string + <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 - “<computeroutput><jemalloc>: </computeroutput>”.</para> + <quote><computeroutput><jemalloc>: </computeroutput></quote>.</para> </refsect1> <refsect1 id="return_values"> <title>RETURN VALUES</title> <refsect2> <title>Standard API</title> - <para>The <function>malloc<parameter/></function> and - <function>calloc<parameter/></function> functions return a pointer to the + <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<parameter/></function> function + <para>The <function>posix_memalign()</function> function returns the value 0 if successful; otherwise it returns an error value. - The <function>posix_memalign<parameter/></function> function will fail + The <function>posix_memalign()</function> function will fail if: <variablelist> <varlistentry> @@ -2602,11 +3218,11 @@ typedef struct { </variablelist> </para> - <para>The <function>aligned_alloc<parameter/></function> function returns + <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<parameter/></function> function will fail if: + <function>aligned_alloc()</function> function will fail if: <variablelist> <varlistentry> <term><errorname>EINVAL</errorname></term> @@ -2623,44 +3239,44 @@ typedef struct { </variablelist> </para> - <para>The <function>realloc<parameter/></function> function returns a + <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<parameter/></function> + allocation failure. The <function>realloc()</function> function always leaves the original buffer intact when an error occurs. </para> - <para>The <function>free<parameter/></function> function returns no + <para>The <function>free()</function> function returns no value.</para> </refsect2> <refsect2> <title>Non-standard API</title> - <para>The <function>mallocx<parameter/></function> and - <function>rallocx<parameter/></function> functions return a pointer to + <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<parameter/></function> function returns the + <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<parameter/></function> function returns the + <para>The <function>sallocx()</function> function returns the real size of the allocation pointed to by <parameter>ptr</parameter>. </para> - <para>The <function>nallocx<parameter/></function> returns the real size + <para>The <function>nallocx()</function> returns the real size that would result from a successful equivalent - <function>mallocx<parameter/></function> function call, or zero if + <function>mallocx()</function> function call, or zero if insufficient memory is available to perform the size computation. </para> - <para>The <function>mallctl<parameter/></function>, - <function>mallctlnametomib<parameter/></function>, and - <function>mallctlbymib<parameter/></function> functions return 0 on + <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> @@ -2696,13 +3312,13 @@ typedef struct { <term><errorname>EFAULT</errorname></term> <listitem><para>An interface with side effects failed in some way - not directly related to <function>mallctl*<parameter/></function> + not directly related to <function>mallctl*()</function> read/write processing.</para></listitem> </varlistentry> </variablelist> </para> - <para>The <function>malloc_usable_size<parameter/></function> function + <para>The <function>malloc_usable_size()</function> function returns the usable size of the allocation pointed to by <parameter>ptr</parameter>. </para> </refsect2> @@ -2727,9 +3343,10 @@ typedef struct { <para>To dump core whenever a problem occurs: <screen>ln -s 'abort:true' /etc/malloc.conf</screen> </para> - <para>To specify in the source a chunk size that is 16 MiB: + <para>To specify in the source that only one arena should be automatically + created: <programlisting language="C"><![CDATA[ -malloc_conf = "lg_chunk:24";]]></programlisting></para> +malloc_conf = "narenas:1";]]></programlisting></para> </refsect1> <refsect1 id="see_also"> <title>SEE ALSO</title> @@ -2750,13 +3367,13 @@ malloc_conf = "lg_chunk:24";]]></programlisting></para> </refsect1> <refsect1 id="standards"> <title>STANDARDS</title> - <para>The <function>malloc<parameter/></function>, - <function>calloc<parameter/></function>, - <function>realloc<parameter/></function>, and - <function>free<parameter/></function> functions conform to ISO/IEC - 9899:1990 (“ISO C90”).</para> - - <para>The <function>posix_memalign<parameter/></function> function conforms - to IEEE Std 1003.1-2001 (“POSIX.1”).</para> + <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> |