Commit-ID: f307cd1a32fab53012b01749a1f5ba10b0a7243f Gitweb: http://git.kernel.org/tip/f307cd1a32fab53012b01749a1f5ba10b0a7243f Author: Mel Gorman <[email protected]> AuthorDate: Mon, 7 Oct 2013 11:28:56 +0100 Committer: Ingo Molnar <[email protected]> CommitDate: Wed, 9 Oct 2013 12:40:21 +0200
sched/numa: Slow scan rate if no NUMA hinting faults are being recorded NUMA PTE scanning slows if a NUMA hinting fault was trapped and no page was migrated. For long-lived but idle processes there may be no faults but the scan rate will be high and just waste CPU. This patch will slow the scan rate for processes that are not trapping faults. Signed-off-by: Mel Gorman <[email protected]> Reviewed-by: Rik van Riel <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Johannes Weiner <[email protected]> Cc: Srikar Dronamraju <[email protected]> Signed-off-by: Peter Zijlstra <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- kernel/sched/fair.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index e08d757..c6c3302 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1039,6 +1039,18 @@ void task_numa_work(struct callback_head *work) out: /* + * If the whole process was scanned without updates then no NUMA + * hinting faults are being recorded and scan rate should be lower. + */ + if (mm->numa_scan_offset == 0 && !nr_pte_updates) { + p->numa_scan_period = min(p->numa_scan_period_max, + p->numa_scan_period << 1); + + next_scan = now + msecs_to_jiffies(p->numa_scan_period); + mm->numa_next_scan = next_scan; + } + + /* * It is possible to reach the end of the VMA list but the last few * VMAs are not guaranteed to the vma_migratable. If they are not, we * would find the !migratable VMA on the next scan but not reset the -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
