From: Shakeel Butt <shakeelb@google.com>
To: David Hildenbrand <david@redhat.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Yang Shi <shy828301@gmail.com>, Zi Yan <ziy@nvidia.com>,
Matthew Wilcox <willy@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: thp: update split_queue_len correctly
Date: Tue, 23 Nov 2021 09:59:11 -0800 [thread overview]
Message-ID: <CALvZod7NzOjQU+h4d39rebRVsR2kco_VTAxyHhZ=fEv6OqAbXw@mail.gmail.com> (raw)
In-Reply-To: <20211123174658.1728753-1-shakeelb@google.com>
On Tue, Nov 23, 2021 at 9:47 AM Shakeel Butt <shakeelb@google.com> wrote:
>
> The deferred THPs are split on memory pressure through shrinker
> callback and splitting of THP during reclaim can fail for several
> reasons like unable to lock the THP, under writeback or unexpected
> number of pins on the THP. Such pages are put back on the deferred split
> list for consideration later. However kernel does not update the
> deferred queue size on putting back the pages whose split was failed.
> This patch fixes that.
I forgot to add the user visible impact.
"Without this patch the split_queue_len can underflow. Shrinker will
always get that there are some THPs to split even if there are not and
waste some cpu to scan the empty list."
next prev parent reply other threads:[~2021-11-23 17:59 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-23 17:46 Shakeel Butt
2021-11-23 17:59 ` Shakeel Butt [this message]
2021-11-23 18:51 ` Yang Shi
2021-11-23 19:03 ` Shakeel Butt
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