linux/fs/proc
KOSAKI Motohiro 0753ba01e1 mm: revert "oom: move oom_adj value"
The commit 2ff05b2b (oom: move oom_adj value) moveed the oom_adj value to
the mm_struct.  It was a very good first step for sanitize OOM.

However Paul Menage reported the commit makes regression to his job
scheduler.  Current OOM logic can kill OOM_DISABLED process.

Why? His program has the code of similar to the following.

	...
	set_oom_adj(OOM_DISABLE); /* The job scheduler never killed by oom */
	...
	if (vfork() == 0) {
		set_oom_adj(0); /* Invoked child can be killed */
		execve("foo-bar-cmd");
	}
	....

vfork() parent and child are shared the same mm_struct.  then above
set_oom_adj(0) doesn't only change oom_adj for vfork() child, it's also
change oom_adj for vfork() parent.  Then, vfork() parent (job scheduler)
lost OOM immune and it was killed.

Actually, fork-setting-exec idiom is very frequently used in userland program.
We must not break this assumption.

Then, this patch revert commit 2ff05b2b and related commit.

Reverted commit list
---------------------
- commit 2ff05b2b4e (oom: move oom_adj value from task_struct to mm_struct)
- commit 4d8b9135c3 (oom: avoid unnecessary mm locking and scanning for OOM_DISABLE)
- commit 8123681022 (oom: only oom kill exiting tasks with attached memory)
- commit 933b787b57 (mm: copy over oom_adj value at fork time)

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-08-18 16:31:13 -07:00
..
array.c proc: avoid information leaks to non-privileged processes 2009-05-04 15:14:23 -07:00
base.c mm: revert "oom: move oom_adj value" 2009-08-18 16:31:13 -07:00
cmdline.c
cpuinfo.c
devices.c
generic.c proc 1/2: do PDE usecounting even for ->read_proc, ->write_proc 2009-03-31 01:14:27 +04:00
inode.c proc 2/2: remove struct proc_dir_entry::owner 2009-03-31 01:14:44 +04:00
internal.h Move junk from proc_fs.h to fs/proc/internal.h 2009-06-11 21:36:01 -04:00
interrupts.c
Kconfig
kcore.c
kmsg.c
loadavg.c sched, timers: cleanup avenrun users 2009-05-15 15:32:45 +02:00
Makefile proc: export statistics for softirq to /proc 2009-06-18 13:03:41 -07:00
meminfo.c mm: remove CONFIG_UNEVICTABLE_LRU config option 2009-06-16 19:47:42 -07:00
mmu.c
nommu.c trivial: fix typo "kernal" -> "kernel" 2009-03-30 15:21:57 +02:00
page.c mm: remove CONFIG_UNEVICTABLE_LRU config option 2009-06-16 19:47:42 -07:00
proc_devtree.c procfs: remove sparse errors in proc_devtree.c 2009-06-18 13:03:41 -07:00
proc_net.c
proc_sysctl.c constify dentry_operations: procfs 2009-03-27 14:44:01 -04:00
proc_tty.c proc tty: remove struct tty_operations::read_proc 2009-04-01 08:59:10 -07:00
root.c Convert obvious places to deactivate_locked_super() 2009-05-09 10:49:40 -04:00
softirqs.c proc: export statistics for softirq to /proc 2009-06-18 13:03:41 -07:00
stat.c proc: export statistics for softirq to /proc 2009-06-18 13:03:41 -07:00
task_mmu.c mm_for_maps: shift down_read(mmap_sem) to the caller 2009-08-10 20:48:32 +10:00
task_nommu.c mm_for_maps: shift down_read(mmap_sem) to the caller 2009-08-10 20:48:32 +10:00
uptime.c Revert "proc: revert /proc/uptime to ->read_proc hook" 2009-03-31 01:14:58 +04:00
version.c
vmcore.c proc: vmcore - use kzalloc in get_new_element() 2009-06-18 13:03:41 -07:00