linux.git/mm/oom_kill.c, branch v2.6.24

oom_kill bug

2007-10-20T22:04:06+00:00

Wrong order of arguments

Signed-off-by: Al Viro 
Signed-off-by: Linus Torvalds

Use helpers to obtain task pid in printks

2007-10-19T18:53:43+00:00

The task_struct->pid member is going to be deprecated, so start
using the helpers (task_pid_nr/task_pid_vnr/task_pid_nr_ns) in
the kernel.

The first thing to start with is the pid, printed to dmesg - in
this case we may safely use task_pid_nr(). Besides, printks produce
more (much more) than a half of all the explicit pid usage.

[akpm@linux-foundation.org: git-drm went and changed lots of stuff]
Signed-off-by: Pavel Emelyanov 
Cc: Dave Airlie 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Isolate some explicit usage of task->tgid

2007-10-19T18:53:40+00:00

With pid namespaces this field is now dangerous to use explicitly, so hide
it behind the helpers.

Also the pid and pgrp fields o task_struct and signal_struct are to be
deprecated.  Unfortunately this patch cannot be sent right now as this
leads to tons of warnings, so start isolating them, and deprecate later.

Actually the p->tgid == pid has to be changed to has_group_leader_pid(),
but Oleg pointed out that in case of posix cpu timers this is the same, and
thread_group_leader() is more preferable.

Signed-off-by: Pavel Emelyanov 
Acked-by: Oleg Nesterov 
Cc: Sukadev Bhattiprolu 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/oom_kill.c: Use list_for_each_entry instead of list_for_each

2007-10-19T18:53:38+00:00

mm/oom_kill.c: Convert list_for_each to list_for_each_entry in
oom_kill_process()

Signed-off-by: Matthias Kaehlcke 
Cc: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pid namespaces: define is_global_init() and is_container_init()

2007-10-19T18:53:37+00:00

is_init() is an ambiguous name for the pid==1 check.  Split it into
is_global_init() and is_container_init().

A cgroup init has it's tsk->pid == 1.

A global init also has it's tsk->pid == 1 and it's active pid namespace
is the init_pid_ns.  But rather than check the active pid namespace,
compare the task structure with 'init_pid_ns.child_reaper', which is
initialized during boot to the /sbin/init process and never changes.

Changelog:

	2.6.22-rc4-mm2-pidns1:
	- Use 'init_pid_ns.child_reaper' to determine if a given task is the
	  global init (/sbin/init) process. This would improve performance
	  and remove dependence on the task_pid().

	2.6.21-mm2-pidns2:

	- [Sukadev Bhattiprolu] Changed is_container_init() calls in {powerpc,
	  ppc,avr32}/traps.c for the _exception() call to is_global_init().
	  This way, we kill only the cgroup if the cgroup's init has a
	  bug rather than force a kernel panic.

[akpm@linux-foundation.org: fix comment]
[sukadev@us.ibm.com: Use is_global_init() in arch/m32r/mm/fault.c]
[bunk@stusta.de: kernel/pid.c: remove unused exports]
[sukadev@us.ibm.com: Fix capability.c to work with threaded init]
Signed-off-by: Serge E. Hallyn 
Signed-off-by: Sukadev Bhattiprolu 
Acked-by: Pavel Emelianov 
Cc: Eric W. Biederman 
Cc: Cedric Le Goater 
Cc: Dave Hansen 
Cc: Herbert Poetzel 
Cc: Kirill Korotaev 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

oom: convert zone_scan_lock from mutex to spinlock

2007-10-17T15:42:46+00:00

There's no reason to sleep in try_set_zone_oom() or clear_zonelist_oom() if
the lock can't be acquired; it will be available soon enough once the zonelist
scanning is done.  All other threads waiting for the OOM killer are also
contingent on the exiting task being able to acquire the lock in
clear_zonelist_oom() so it doesn't make sense to put it to sleep.

Cc: Andrea Arcangeli 
Cc: Christoph Lameter 
Signed-off-by: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

oom: do not take callback_mutex

2007-10-17T15:42:46+00:00

Since no task descriptor's 'cpuset' field is dereferenced in the execution of
the OOM killer anymore, it is no longer necessary to take callback_mutex.

[akpm@linux-foundation.org: restore cpuset_lock for other patches]
Cc: Andrea Arcangeli 
Acked-by: Christoph Lameter 
Signed-off-by: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

oom: compare cpuset mems_allowed instead of exclusive ancestors

2007-10-17T15:42:46+00:00

Instead of testing for overlap in the memory nodes of the the nearest
exclusive ancestor of both current and the candidate task, it is better to
simply test for intersection between the task's mems_allowed in their task
descriptors.  This does not require taking callback_mutex since it is only
used as a hint in the badness scoring.

Tasks that do not have an intersection in their mems_allowed with the current
task are not explicitly restricted from being OOM killed because it is quite
possible that the candidate task has allocated memory there before and has
since changed its mems_allowed.

Cc: Andrea Arcangeli 
Acked-by: Christoph Lameter 
Signed-off-by: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

oom: suppress extraneous stack and memory dump

2007-10-17T15:42:46+00:00

Suppresses the extraneous stack and memory dump when a parallel OOM killing
has been found.  There's no need to fill the ring buffer with this information
if its already been printed and the condition that triggered the previous OOM
killer has not yet been alleviated.

Cc: Andrea Arcangeli 
Acked-by: Christoph Lameter 
Signed-off-by: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

oom: add oom_kill_allocating_task sysctl

2007-10-17T15:42:46+00:00

Adds a new sysctl, 'oom_kill_allocating_task', which will automatically kill
the OOM-triggering task instead of scanning through the tasklist to find a
memory-hogging target.  This is helpful for systems with an insanely large
number of tasks where scanning the tasklist significantly degrades
performance.

Cc: Andrea Arcangeli 
Acked-by: Christoph Lameter 
Signed-off-by: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds