Messages in this thread | | | Date | Tue, 24 Jan 2012 11:45:52 +0800 | Subject | Re: [PATCH] mm: vmscan: check mem cgroup over reclaimed | From | Hillf Danton <> |
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Hi all
On Tue, Jan 24, 2012 at 3:04 AM, Ying Han <yinghan@google.com> wrote: > On Sun, Jan 22, 2012 at 5:55 PM, Hillf Danton <dhillf@gmail.com> wrote: >> To avoid reduction in performance of reclaimee, checking overreclaim is added >> after shrinking lru list, when pages are reclaimed from mem cgroup. >> >> If over reclaim occurs, shrinking remaining lru lists is skipped, and no more >> reclaim for reclaim/compaction. >> >> Signed-off-by: Hillf Danton <dhillf@gmail.com> >> --- >> >> --- a/mm/vmscan.c Mon Jan 23 00:23:10 2012 >> +++ b/mm/vmscan.c Mon Jan 23 09:57:20 2012 >> @@ -2086,6 +2086,7 @@ static void shrink_mem_cgroup_zone(int p >> unsigned long nr_reclaimed, nr_scanned; >> unsigned long nr_to_reclaim = sc->nr_to_reclaim; >> struct blk_plug plug; >> + bool memcg_over_reclaimed = false; >> >> restart: >> nr_reclaimed = 0; >> @@ -2103,6 +2104,11 @@ restart: >> >> nr_reclaimed += shrink_list(lru, nr_to_scan, >> mz, sc, priority); >> + >> + memcg_over_reclaimed = !scanning_global_lru(mz) >> + && (nr_reclaimed >= nr_to_reclaim); >> + if (memcg_over_reclaimed) >> + goto out; > > Why we need the change here? Do we have number to demonstrate?
See below please 8-)
> > >> } >> } >> /* >> @@ -2116,6 +2122,7 @@ restart: >> if (nr_reclaimed >= nr_to_reclaim && priority < DEF_PRIORITY) >> break; >> } >> +out: >> blk_finish_plug(&plug); >> sc->nr_reclaimed += nr_reclaimed; >> >> @@ -2127,7 +2134,8 @@ restart: >> shrink_active_list(SWAP_CLUSTER_MAX, mz, sc, priority, 0); >> >> /* reclaim/compaction might need reclaim to continue */ >> - if (should_continue_reclaim(mz, nr_reclaimed, >> + if (!memcg_over_reclaimed && >> + should_continue_reclaim(mz, nr_reclaimed, >> sc->nr_scanned - nr_scanned, sc)) > > This changes the existing logic. What if the nr_reclaimed is greater > than nr_to_reclaim, but smaller than pages_for_compaction? The > existing logic is to continue reclaiming. > With soft limit available, what if nr_to_reclaim set to be the number of pages exceeding soft limit? With over reclaim abused, what are the targets of soft limit?
Thanks Hillf -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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