Commit da99ecf1 authored by Michal Hocko's avatar Michal Hocko Committed by Linus Torvalds
Browse files

mm: replace TIF_MEMDIE checks by tsk_is_oom_victim 

TIF_MEMDIE is set only to the tasks whick were either directly selected
by the OOM killer or passed through mark_oom_victim from the allocator
path.  tsk_is_oom_victim is more generic and allows to identify all
tasks (threads) which share the mm with the oom victim.

Please note that the freezer still needs to check TIF_MEMDIE because we
cannot thaw tasks which do not participage in oom_victims counting
otherwise a !TIF_MEMDIE task could interfere after oom_disbale returns.

Link: http://lkml.kernel.org/r/20170810075019.28998-3-mhocko@kernel.org


Signed-off-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent cd04ae1e

kernel/cgroup/cpuset.c

+5 −4
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ 
#include <linux/time64.h>

#include <linux/backing-dev.h>

#include <linux/sort.h>

#include <linux/oom.h>



#include <linux/uaccess.h>

#include <linux/atomic.h>
@@ -2500,12 +2501,12 @@ static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs) 
 * If we're in interrupt, yes, we can always allocate.  If @node is set in

 * current's mems_allowed, yes.  If it's not a __GFP_HARDWALL request and this

 * node is set in the nearest hardwalled cpuset ancestor to current's cpuset,

 * yes.  If current has access to memory reserves due to TIF_MEMDIE, yes.

 * yes.  If current has access to memory reserves as an oom victim, yes.

 * Otherwise, no.

 *

 * GFP_USER allocations are marked with the __GFP_HARDWALL bit,

 * and do not allow allocations outside the current tasks cpuset

 * unless the task has been OOM killed as is marked TIF_MEMDIE.

 * unless the task has been OOM killed.

 * GFP_KERNEL allocations are not so marked, so can escape to the

 * nearest enclosing hardwalled ancestor cpuset.

 *
@@ -2528,7 +2529,7 @@ static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs) 
 * affect that:

 *	in_interrupt - any node ok (current task context irrelevant)

 *	GFP_ATOMIC   - any node ok

 *	TIF_MEMDIE   - any node ok

 *	tsk_is_oom_victim   - any node ok

 *	GFP_KERNEL   - any node in enclosing hardwalled cpuset ok

 *	GFP_USER     - only nodes in current tasks mems allowed ok.

 */
@@ -2546,7 +2547,7 @@ bool __cpuset_node_allowed(int node, gfp_t gfp_mask) 
	 * Allow tasks that have access to memory reserves because they have

	 * been OOM killed to get memory anywhere.

	 */

	if (unlikely(test_thread_flag(TIF_MEMDIE)))

	if (unlikely(tsk_is_oom_victim(current)))

		return true;

	if (gfp_mask & __GFP_HARDWALL)	/* If hardwall request, stop here */

		return false;

mm/memcontrol.c

+1 −1
Original line number Diff line number Diff line
@@ -1917,7 +1917,7 @@ retry: 
	 * bypass the last charges so that they can exit quickly and

	 * free their memory.

	 */

	if (unlikely(test_thread_flag(TIF_MEMDIE) ||

	if (unlikely(tsk_is_oom_victim(current) ||

		     fatal_signal_pending(current) ||

		     current->flags & PF_EXITING))

		goto force;

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