Messages in this thread | | | Subject | Re: [v7 PATCH 1/2] mm: vmscan: remove double slab pressure by inc'ing sc->nr_scanned | From | Yang Shi <> | Date | Tue, 11 Jun 2019 10:17:39 -0700 |
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On 6/11/19 10:12 AM, Yang Shi wrote: > > > On 6/10/19 2:36 PM, Oscar Salvador wrote: >> On Tue, 2019-05-28 at 14:44 +0800, Yang Shi wrote: >>> The commit 9092c71bb724 ("mm: use sc->priority for slab shrink >>> targets") >>> has broken up the relationship between sc->nr_scanned and slab >>> pressure. >>> The sc->nr_scanned can't double slab pressure anymore. So, it sounds >>> no >>> sense to still keep sc->nr_scanned inc'ed. Actually, it would >>> prevent >>> from adding pressure on slab shrink since excessive sc->nr_scanned >>> would >>> prevent from scan->priority raise. >> Hi Yang, >> >> I might be misunderstanding this, but did you mean "prevent from scan- >> priority decreasing"? >> I guess we are talking about balance_pgdat(), and in case >> kswapd_shrink_node() returns true (it means we have scanned more than >> we had to reclaim), raise_priority becomes false, and this does not let >> sc->priority to be decreased, which has the impact that less pages will >> be reclaimed the next round. > > Yes, exactly.
BTW, for the scan priority, the smaller number the higher priority. So, either "raise" or "decrease" sounds correct. "raise" means the real priority, "decrease" means the number itself.
> >> >> Sorry for bugging here, I just wanted to see if I got this right. >> >> >
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