From: Chris Down <chris@chrisdown.name>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Muchun Song <songmuchun@bytedance.com>,
Michal Hocko <mhocko@kernel.org>,
Matthew Wilcox <willy@infradead.org>,
Chunxin Zang <zangchunxin@bytedance.com>
Subject: Re: [PATCH] mm, vmscan: guarantee drop_slab_node() termination
Date: Wed, 18 Aug 2021 22:48:52 +0100 [thread overview]
Message-ID: <YR2ARISBFq8O6tSN@chrisdown.name> (raw)
In-Reply-To: <20210818152239.25502-1-vbabka@suse.cz>
Vlastimil Babka writes:
>@@ -948,7 +949,7 @@ void drop_slab_node(int nid)
> do {
> freed += shrink_slab(GFP_KERNEL, nid, memcg, 0);
> } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
>- } while (freed > 10);
>+ } while ((freed >> shift++) > 0);
I think this is a good idea, thanks for bringing it up :-)
I'm not sure about the bitshift idea, though. It certainly makes sure that even
large, continuous periods of reclaim eventually terminates, but I find it hard
to reason about -- for example, if there's a lot of parallel activity, that
might result in 10 constantly reintroduced pages, or 1000 pages, and it's not
immediately obvious that we should treat those differently.
What about using MAX_RECLAIM_RETRIES? There's already precedent for using it in
non-OOM scenarios, like mem_cgroup_handle_over_high.
next prev parent reply other threads:[~2021-08-18 21:48 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-18 15:22 [PATCH] mm, vmscan: guarantee drop_slab_node() termination Vlastimil Babka
2021-08-18 21:48 ` Chris Down [this message]
2021-08-19 2:55 ` Kefeng Wang
2021-08-19 7:01 ` Vlastimil Babka
2021-08-19 9:38 ` Kefeng Wang
2021-08-19 13:21 ` Chris Down
2021-08-19 14:16 ` Michal Hocko
2021-08-24 9:33 ` Vlastimil Babka
2021-08-24 10:02 ` Matthew Wilcox
2021-08-24 14:04 ` Vlastimil Babka
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