linux/fs/proc
Eric W. Biederman 99f8955183 [PATCH] proc: don't lock task_structs indefinitely
Every inode in /proc holds a reference to a struct task_struct.  If a
directory or file is opened and remains open after the the task exits this
pinning continues.  With 8K stacks on a 32bit machine the amount pinned per
file descriptor is about 10K.

Normally I would figure a reasonable per user process limit is about 100
processes.  With 80 processes, with a 1000 file descriptors each I can trigger
the 00M killer on a 32bit kernel, because I have pinned about 800MB of useless
data.

This patch replaces the struct task_struct pointer with a pointer to a struct
task_ref which has a struct task_struct pointer.  The so the pinning of dead
tasks does not happen.

The code now has to contend with the fact that the task may now exit at any
time.  Which is a little but not muh more complicated.

With this change it takes about 1000 processes each opening up 1000 file
descriptors before I can trigger the OOM killer.  Much better.

[mlp@google.com: task_mmu small fixes]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Paul Jackson <pj@sgi.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Albert Cahalan <acahalan@gmail.com>
Signed-off-by: Prasanna Meda <mlp@google.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:25 -07:00
..
array.c [PATCH] hrtimers: remove it_real_value calculation from proc/*/stat 2006-03-26 08:57:02 -08:00
base.c [PATCH] proc: don't lock task_structs indefinitely 2006-06-26 09:58:25 -07:00
generic.c [PATCH] mark f_ops const in the inode 2006-03-28 09:16:05 -08:00
inode-alloc.txt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
inode.c [PATCH] proc: don't lock task_structs indefinitely 2006-06-26 09:58:25 -07:00
internal.h [PATCH] proc: don't lock task_structs indefinitely 2006-06-26 09:58:25 -07:00
kcore.c [PATCH] Make most file operations structs in fs/ const 2006-03-28 09:16:06 -08:00
kmsg.c [PATCH] Make most file operations structs in fs/ const 2006-03-28 09:16:06 -08:00
Makefile [PATCH] kdump: Access dump file in elf format (/proc/vmcore) 2005-06-25 16:24:53 -07:00
mmu.c [PATCH] fix impossible VmallocChunk 2005-05-17 07:59:10 -07:00
nommu.c [PATCH] output of /proc/maps on nommu systems is incomplete 2005-10-17 17:03:57 -07:00
proc_devtree.c [PATCH] powerpc: Cope with duplicate node & property names in /proc/device-tree 2006-03-28 16:45:23 +11:00
proc_misc.c [PATCH] Simplify proc/devices and fix early termination regression 2006-03-31 12:18:53 -08:00
proc_tty.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
root.c [PATCH] VFS: Permit filesystem to override root dentry on mount 2006-06-23 07:42:45 -07:00
task_mmu.c [PATCH] proc: don't lock task_structs indefinitely 2006-06-26 09:58:25 -07:00
task_nommu.c [PATCH] proc: Move proc_maps_operations into task_mmu.c 2006-06-26 09:58:24 -07:00
vmcore.c [PATCH] kdump proc vmcore size oveflow fix 2006-04-11 06:18:42 -07:00