sched/numa: Slow down scan rate if shared faults dominate

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The comment above update_task_scan_period() says the scan period should
be increased (scanning slows down) if the majority of memory accesses
are on the local node, or if the majority of the page accesses are
shared with other tasks.

However, with the current code, all a high ratio of shared accesses
does is slow down the rate at which scanning is made faster.

This patch changes things so either lots of shared accesses or
lots of local accesses will slow down scanning, and numa scanning
is sped up only when there are lots of private faults on remote
memory pages.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: jhladky@redhat.com
Cc: lvenanci@redhat.com
Link: http://lkml.kernel.org/r/20170731192847.23050-2-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

...

This commit is contained in:

Rik van Riel 2017-07-31 15:28:46 -04:00 • committed by Ingo Molnar

parent f235a54f00

commit 37ec97deb3

1 changed files with 25 additions and 14 deletions

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kernel/sched/fair.c

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