Messages in this thread | | | Date | Thu, 20 Jan 2022 09:24:22 +0100 | From | Michal Hocko <> | Subject | Re: [RESEND][PATCH v2] mm: don't call lru draining in the nested lru_cache_disable |
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On Wed 19-01-22 20:25:54, Minchan Kim wrote: > On Wed, Jan 19, 2022 at 10:20:22AM +0100, Michal Hocko wrote: [...] > > What does prevent you from calling lru_cache_{disable,enable} this way > > with the existing implementation? AFAICS calls can be nested just fine. > > Or am I missing something? > > It just increases more IPI calls since we drain the lru cache > both upper layer and lower layer. That's I'd like to avoid > in this patch. Just disable lru cache one time for entire > allocation path.
I do not follow. Once you call lru_cache_disable at the higher level then no new pages are going to be added to the pcp caches. At the same time existing caches are flushed so the inner lru_cache_disable will not trigger any new IPIs.
-- Michal Hocko SUSE Labs
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