From: Johannes Weiner <hannes@cmpxchg.org>
To: Yu Zhao <yuzhao@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Vlastimil Babka <vbabka@suse.cz>,
linux-mm@kvack.org
Subject: Re: [PATCH] mm: don't SetPageWorkingset unconditionally during swapin
Date: Thu, 10 Dec 2020 05:47:26 -0500 [thread overview]
Message-ID: <20201210104726.GA264602@cmpxchg.org> (raw)
In-Reply-To: <20201209012400.1771150-1-yuzhao@google.com>
On Tue, Dec 08, 2020 at 06:24:00PM -0700, Yu Zhao wrote:
> We are capable of SetPageWorkingset based on refault distances after
> commit aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU")
> This is done by workingset_refault(), which is right above the
> unconditional SetPageWorkingset deleted by this patch.
>
> The unconditional SetPageWorkingset miscategorizes pages that are
> read ahead or never belonged to the working set (e.g., tmpfs pages
> accessed by fd). When those pages are swapped in (after they were
> swapped out) for the first time, they skew PSI (when using
> async swap). When this happens again, depending on their refault
> distances, they might skew workingset_restore_anon counter in
> addition to PSI because their shadows say they were part of the
> working set.
>
> Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
next prev parent reply other threads:[~2020-12-10 10:49 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-09 1:24 [PATCH] mm: don't SetPageWorkingset unconditionally during swapin Yu Zhao
2020-12-09 9:18 ` Vlastimil Babka
2020-12-10 11:21 ` Johannes Weiner
2020-12-10 22:44 ` Yu Zhao
2020-12-14 16:09 ` Michal Hocko
2020-12-14 23:12 ` [PATCH] mm/swap: " Yu Zhao
2020-12-10 10:47 ` Johannes Weiner [this message]
2020-12-10 12:06 ` [PATCH] mm: " Joonsoo Kim
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