From: Shakeel Butt <shakeelb@google.com>
To: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Vlastimil Babka <vbabka@suse.cz>,
Matthew Wilcox <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linux MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [v2 PATCH 2/2] mm: swap: use smp_mb__after_atomic() to order LRU bit set
Date: Mon, 16 Mar 2020 16:47:15 -0700 [thread overview]
Message-ID: <CALvZod4pn1XJN7EVV9w6t2cYkHWG++GB6pJdBzBJO+w4k8aEEw@mail.gmail.com> (raw)
In-Reply-To: <1584397455-28701-2-git-send-email-yang.shi@linux.alibaba.com>
On Mon, Mar 16, 2020 at 3:24 PM Yang Shi <yang.shi@linux.alibaba.com> wrote:
>
> Memory barrier is needed after setting LRU bit, but smp_mb() is too
> strong. Some architectures, i.e. x86, imply memory barrier with atomic
> operations, so replacing it with smp_mb__after_atomic() sounds better,
> which is nop on strong ordered machines, and full memory barriers on
> others. With this change the vm-calability cases would perform better
> on x86, I saw total 6% improvement with this patch and previous inline
> fix.
>
> The test data (lru-file-readtwice throughput) against v5.6-rc4:
> mainline w/ inline fix w/ both (adding this)
> 150MB 154MB 159MB
>
> Fixes: 9c4e6b1a7027 ("mm, mlock, vmscan: no more skipping pagevecs")
> Cc: Shakeel Butt <shakeelb@google.com>
> Acked-by: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Reviewed-and-Tested-by: Shakeel Butt <shakeelb@google.com>
next prev parent reply other threads:[~2020-03-16 23:47 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-16 22:24 [v2 PATCH 1/2] mm: swap: make page_evictable() inline Yang Shi
2020-03-16 22:24 ` [v2 PATCH 2/2] mm: swap: use smp_mb__after_atomic() to order LRU bit set Yang Shi
2020-03-16 23:47 ` Shakeel Butt [this message]
2020-03-16 23:46 ` [v2 PATCH 1/2] mm: swap: make page_evictable() inline Shakeel Butt
2020-03-17 2:05 ` Yang Shi
2020-03-17 3:00 ` kbuild test robot
2020-03-17 3:24 ` Yang Shi
2020-03-17 3:15 ` kbuild test robot
2020-03-17 8:59 ` Vlastimil Babka
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