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authorIngo Molnar <mingo@elte.hu>2008-10-28 16:26:12 +0100
committerIngo Molnar <mingo@elte.hu>2008-10-28 16:26:12 +0100
commit7a9787e1eba95a166265e6a260cf30af04ef0a99 (patch)
treee730a4565e0318140d2fbd2f0415d18a339d7336 /Documentation/filesystems/proc.txt
parent41b9eb264c8407655db57b60b4457fe1b2ec9977 (diff)
parent0173a3265b228da319ceb9c1ec6a5682fd1b2d92 (diff)
downloadlinux-7a9787e1eba95a166265e6a260cf30af04ef0a99.tar.gz
Merge commit 'v2.6.28-rc2' into x86/pci-ioapic-boot-irq-quirks
Diffstat (limited to 'Documentation/filesystems/proc.txt')
-rw-r--r--Documentation/filesystems/proc.txt177
1 files changed, 127 insertions, 50 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 7f268f327d75..bcceb99b81dd 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -296,6 +296,7 @@ Table 1-4: Kernel info in /proc
uptime System uptime
version Kernel version
video bttv info of video resources (2.4)
+ vmallocinfo Show vmalloced areas
..............................................................................
You can, for example, check which interrupts are currently in use and what
@@ -557,6 +558,49 @@ VmallocTotal: total size of vmalloc memory area
VmallocUsed: amount of vmalloc area which is used
VmallocChunk: largest contigious block of vmalloc area which is free
+..............................................................................
+
+vmallocinfo:
+
+Provides information about vmalloced/vmaped areas. One line per area,
+containing the virtual address range of the area, size in bytes,
+caller information of the creator, and optional information depending
+on the kind of area :
+
+ pages=nr number of pages
+ phys=addr if a physical address was specified
+ ioremap I/O mapping (ioremap() and friends)
+ vmalloc vmalloc() area
+ vmap vmap()ed pages
+ user VM_USERMAP area
+ vpages buffer for pages pointers was vmalloced (huge area)
+ N<node>=nr (Only on NUMA kernels)
+ Number of pages allocated on memory node <node>
+
+> cat /proc/vmallocinfo
+0xffffc20000000000-0xffffc20000201000 2101248 alloc_large_system_hash+0x204 ...
+ /0x2c0 pages=512 vmalloc N0=128 N1=128 N2=128 N3=128
+0xffffc20000201000-0xffffc20000302000 1052672 alloc_large_system_hash+0x204 ...
+ /0x2c0 pages=256 vmalloc N0=64 N1=64 N2=64 N3=64
+0xffffc20000302000-0xffffc20000304000 8192 acpi_tb_verify_table+0x21/0x4f...
+ phys=7fee8000 ioremap
+0xffffc20000304000-0xffffc20000307000 12288 acpi_tb_verify_table+0x21/0x4f...
+ phys=7fee7000 ioremap
+0xffffc2000031d000-0xffffc2000031f000 8192 init_vdso_vars+0x112/0x210
+0xffffc2000031f000-0xffffc2000032b000 49152 cramfs_uncompress_init+0x2e ...
+ /0x80 pages=11 vmalloc N0=3 N1=3 N2=2 N3=3
+0xffffc2000033a000-0xffffc2000033d000 12288 sys_swapon+0x640/0xac0 ...
+ pages=2 vmalloc N1=2
+0xffffc20000347000-0xffffc2000034c000 20480 xt_alloc_table_info+0xfe ...
+ /0x130 [x_tables] pages=4 vmalloc N0=4
+0xffffffffa0000000-0xffffffffa000f000 61440 sys_init_module+0xc27/0x1d00 ...
+ pages=14 vmalloc N2=14
+0xffffffffa000f000-0xffffffffa0014000 20480 sys_init_module+0xc27/0x1d00 ...
+ pages=4 vmalloc N1=4
+0xffffffffa0014000-0xffffffffa0017000 12288 sys_init_module+0xc27/0x1d00 ...
+ pages=2 vmalloc N1=2
+0xffffffffa0017000-0xffffffffa0022000 45056 sys_init_module+0xc27/0x1d00 ...
+ pages=10 vmalloc N0=10
1.3 IDE devices in /proc/ide
----------------------------
@@ -879,45 +923,44 @@ CPUs.
The "procs_blocked" line gives the number of processes currently blocked,
waiting for I/O to complete.
+
1.9 Ext4 file system parameters
------------------------------
-Ext4 file system have one directory per partition under /proc/fs/ext4/
-# ls /proc/fs/ext4/hdc/
-group_prealloc max_to_scan mb_groups mb_history min_to_scan order2_req
-stats stream_req
-
-mb_groups:
-This file gives the details of mutiblock allocator buddy cache of free blocks
-
-mb_history:
-Multiblock allocation history.
-stats:
-This file indicate whether the multiblock allocator should start collecting
-statistics. The statistics are shown during unmount
+Information about mounted ext4 file systems can be found in
+/proc/fs/ext4. Each mounted filesystem will have a directory in
+/proc/fs/ext4 based on its device name (i.e., /proc/fs/ext4/hdc or
+/proc/fs/ext4/dm-0). The files in each per-device directory are shown
+in Table 1-10, below.
-group_prealloc:
-The multiblock allocator normalize the block allocation request to
-group_prealloc filesystem blocks if we don't have strip value set.
-The stripe value can be specified at mount time or during mke2fs.
-
-max_to_scan:
-How long multiblock allocator can look for a best extent (in found extents)
-
-min_to_scan:
-How long multiblock allocator must look for a best extent
-
-order2_req:
-Multiblock allocator use 2^N search using buddies only for requests greater
-than or equal to order2_req. The request size is specfied in file system
-blocks. A value of 2 indicate only if the requests are greater than or equal
-to 4 blocks.
+Table 1-10: Files in /proc/fs/ext4/<devname>
+..............................................................................
+ File Content
+ mb_groups details of multiblock allocator buddy cache of free blocks
+ mb_history multiblock allocation history
+ stats controls whether the multiblock allocator should start
+ collecting statistics, which are shown during the unmount
+ group_prealloc the multiblock allocator will round up allocation
+ requests to a multiple of this tuning parameter if the
+ stripe size is not set in the ext4 superblock
+ max_to_scan The maximum number of extents the multiblock allocator
+ will search to find the best extent
+ min_to_scan The minimum number of extents the multiblock allocator
+ will search to find the best extent
+ order2_req Tuning parameter which controls the minimum size for
+ requests (as a power of 2) where the buddy cache is
+ used
+ stream_req Files which have fewer blocks than this tunable
+ parameter will have their blocks allocated out of a
+ block group specific preallocation pool, so that small
+ files are packed closely together. Each large file
+ will have its blocks allocated out of its own unique
+ preallocation pool.
+inode_readahead Tuning parameter which controls the maximum number of
+ inode table blocks that ext4's inode table readahead
+ algorithm will pre-read into the buffer cache
+..............................................................................
-stream_req:
-Files smaller than stream_req are served by the stream allocator, whose
-purpose is to pack requests as close each to other as possible to
-produce smooth I/O traffic. Avalue of 16 indicate that file smaller than 16
-filesystem block size will use group based preallocation.
------------------------------------------------------------------------------
Summary
@@ -1278,6 +1321,18 @@ debugging information is displayed on console.
NMI switch that most IA32 servers have fires unknown NMI up, for example.
If a system hangs up, try pressing the NMI switch.
+panic_on_unrecovered_nmi
+------------------------
+
+The default Linux behaviour on an NMI of either memory or unknown is to continue
+operation. For many environments such as scientific computing it is preferable
+that the box is taken out and the error dealt with than an uncorrected
+parity/ECC error get propogated.
+
+A small number of systems do generate NMI's for bizarre random reasons such as
+power management so the default is off. That sysctl works like the existing
+panic controls already in that directory.
+
nmi_watchdog
------------
@@ -1288,12 +1343,24 @@ determine whether or not they are still functioning properly.
Because the NMI watchdog shares registers with oprofile, by disabling the NMI
watchdog, oprofile may have more registers to utilize.
-maps_protect
-------------
+msgmni
+------
+
+Maximum number of message queue ids on the system.
+This value scales to the amount of lowmem. It is automatically recomputed
+upon memory add/remove or ipc namespace creation/removal.
+When a value is written into this file, msgmni's value becomes fixed, i.e. it
+is not recomputed anymore when one of the above events occurs.
+Use auto_msgmni to change this behavior.
-Enables/Disables the protection of the per-process proc entries "maps" and
-"smaps". When enabled, the contents of these files are visible only to
-readers that are allowed to ptrace() the given process.
+auto_msgmni
+-----------
+
+Enables/Disables automatic recomputing of msgmni upon memory add/remove or
+upon ipc namespace creation/removal (see the msgmni description above).
+Echoing "1" into this file enables msgmni automatic recomputing.
+Echoing "0" turns it off.
+auto_msgmni default value is 1.
2.4 /proc/sys/vm - The virtual memory subsystem
@@ -1317,15 +1384,18 @@ causes the kernel to prefer to reclaim dentries and inodes.
dirty_background_ratio
----------------------
-Contains, as a percentage of total system memory, the number of pages at which
-the pdflush background writeback daemon will start writing out dirty data.
+Contains, as a percentage of the dirtyable system memory (free pages + mapped
+pages + file cache, not including locked pages and HugePages), the number of
+pages at which the pdflush background writeback daemon will start writing out
+dirty data.
dirty_ratio
-----------------
-Contains, as a percentage of total system memory, the number of pages at which
-a process which is generating disk writes will itself start writing out dirty
-data.
+Contains, as a percentage of the dirtyable system memory (free pages + mapped
+pages + file cache, not including locked pages and HugePages), the number of
+pages at which a process which is generating disk writes will itself start
+writing out dirty data.
dirty_writeback_centisecs
-------------------------
@@ -1430,7 +1500,7 @@ used because pages_free(1355) is smaller than watermark + protection[2]
normal page requirement. If requirement is DMA zone(index=0), protection[0]
(=0) is used.
-zone[i]'s protection[j] is calculated by following exprssion.
+zone[i]'s protection[j] is calculated by following expression.
(i < j):
zone[i]->protection[j]
@@ -2345,22 +2415,29 @@ will be dumped when the <pid> process is dumped. coredump_filter is a bitmask
of memory types. If a bit of the bitmask is set, memory segments of the
corresponding memory type are dumped, otherwise they are not dumped.
-The following 4 memory types are supported:
+The following 7 memory types are supported:
- (bit 0) anonymous private memory
- (bit 1) anonymous shared memory
- (bit 2) file-backed private memory
- (bit 3) file-backed shared memory
+ - (bit 4) ELF header pages in file-backed private memory areas (it is
+ effective only if the bit 2 is cleared)
+ - (bit 5) hugetlb private memory
+ - (bit 6) hugetlb shared memory
Note that MMIO pages such as frame buffer are never dumped and vDSO pages
are always dumped regardless of the bitmask status.
-Default value of coredump_filter is 0x3; this means all anonymous memory
-segments are dumped.
+ Note bit 0-4 doesn't effect any hugetlb memory. hugetlb memory are only
+ effected by bit 5-6.
+
+Default value of coredump_filter is 0x23; this means all anonymous memory
+segments and hugetlb private memory are dumped.
If you don't want to dump all shared memory segments attached to pid 1234,
-write 1 to the process's proc file.
+write 0x21 to the process's proc file.
- $ echo 0x1 > /proc/1234/coredump_filter
+ $ echo 0x21 > /proc/1234/coredump_filter
When a new process is created, the process inherits the bitmask status from its
parent. It is useful to set up coredump_filter before the program runs.