sched/numa: Do statistics calculation using local variables only
authorRik van Riel <riel@redhat.com>
Mon, 27 Jan 2014 22:03:46 +0000 (17:03 -0500)
committerIngo Molnar <mingo@kernel.org>
Tue, 28 Jan 2014 14:03:17 +0000 (15:03 +0100)
commit35664fd41e1c8cc4f0b89f6a51db5af39ba50640
treebafac16f345f34d673d4d58f51a302137b4d7481
parent7e2703e6099609adc93679c4d45cd6247f565971
sched/numa: Do statistics calculation using local variables only

The current code in task_numa_placement calculates the difference
between the old and the new value, but also temporarily stores half
of the old value in the per-process variables.

The NUMA balancing code looks at those per-process variables, and
having other tasks temporarily see halved statistics could lead to
unwanted numa migrations. This can be avoided by doing all the math
in local variables.

This change also simplifies the code a little.

Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Chegu Vinod <chegu_vinod@hp.com>
Link: http://lkml.kernel.org/r/1390860228-21539-8-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kernel/sched/fair.c