linux/fs/proc
David Rientjes 2ff05b2b4e oom: move oom_adj value from task_struct to mm_struct
The per-task oom_adj value is a characteristic of its mm more than the
task itself since it's not possible to oom kill any thread that shares the
mm.  If a task were to be killed while attached to an mm that could not be
freed because another thread were set to OOM_DISABLE, it would have
needlessly been terminated since there is no potential for future memory
freeing.

This patch moves oomkilladj (now more appropriately named oom_adj) from
struct task_struct to struct mm_struct.  This requires task_lock() on a
task to check its oom_adj value to protect against exec, but it's already
necessary to take the lock when dereferencing the mm to find the total VM
size for the badness heuristic.

This fixes a livelock if the oom killer chooses a task and another thread
sharing the same memory has an oom_adj value of OOM_DISABLE.  This occurs
because oom_kill_task() repeatedly returns 1 and refuses to kill the
chosen task while select_bad_process() will repeatedly choose the same
task during the next retry.

Taking task_lock() in select_bad_process() to check for OOM_DISABLE and in
oom_kill_task() to check for threads sharing the same memory will be
removed in the next patch in this series where it will no longer be
necessary.

Writing to /proc/pid/oom_adj for a kthread will now return -EINVAL since
these threads are immune from oom killing already.  They simply report an
oom_adj value of OOM_DISABLE.

Cc: Nick Piggin <npiggin@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16 19:47:43 -07:00
..
array.c proc: avoid information leaks to non-privileged processes 2009-05-04 15:14:23 -07:00
base.c oom: move oom_adj value from task_struct to mm_struct 2009-06-16 19:47:43 -07:00
cmdline.c proc: switch /proc/cmdline to seq_file 2008-10-23 14:29:04 +04:00
cpuinfo.c proc: move /proc/cpuinfo code to fs/proc/cpuinfo.c 2008-10-23 15:05:11 +04:00
devices.c proc: move /proc/devices code to fs/proc/devices.c 2008-10-23 15:02:18 +04:00
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 proc: move /proc/interrupts boilerplate code to fs/proc/interrupts.c 2008-10-23 15:15:46 +04:00
Kconfig proc: move PROC_PAGE_MONITOR to fs/proc/Kconfig 2008-10-10 04:18:57 +04:00
kcore.c proc: move all /proc/kcore stuff to fs/proc/kcore.c 2008-10-23 18:32:38 +04:00
kmsg.c proc: move /proc/kmsg creation to fs/proc/kmsg.c 2008-10-23 14:35:08 +04:00
loadavg.c sched, timers: cleanup avenrun users 2009-05-15 15:32:45 +02:00
Makefile proc: remove fs/proc/proc_misc.c 2008-10-23 18:54:05 +04:00
meminfo.c mm: remove CONFIG_UNEVICTABLE_LRU config option 2009-06-16 19:47:42 -07:00
mmu.c fs/proc/mmu.c: headers butchery 2007-10-17 08:42:48 -07:00
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 Move junk from proc_fs.h to fs/proc/internal.h 2009-06-11 21:36:01 -04:00
proc_net.c proc: stop using BKL 2009-01-05 12:27:44 +03:00
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
stat.c [S390] /proc/stat idle field for idle cpus 2009-04-23 13:58:17 +02:00
task_mmu.c pagemap: require aligned-length, non-null reads of /proc/pid/pagemap 2009-05-02 15:36:09 -07:00
task_nommu.c nommu: fix typo vma->pg_off to vma->vm_pgoff 2009-04-08 10:21:44 -07:00
uptime.c Revert "proc: revert /proc/uptime to ->read_proc hook" 2009-03-31 01:14:58 +04:00
version.c proc: switch /proc/version to seq_file 2008-10-23 14:19:58 +04:00
vmcore.c vmcore: remove saved_max_pfn check 2009-01-08 08:31:14 -08:00