From: Alex Shi <alex.shi@linux.alibaba.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, akpm@linux-foundation.org,
mgorman@techsingularity.net, tj@kernel.org, hughd@google.com,
khlebnikov@yandex-team.ru, daniel.m.jordan@oracle.com,
yang.shi@linux.alibaba.com, Johannes Weiner <hannes@cmpxchg.org>,
Roman Gushchin <guro@fb.com>, Shakeel Butt <shakeelb@google.com>,
Chris Down <chris@chrisdown.name>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v2 6/8] mm/lru: remove rcu_read_lock to fix performance regression
Date: Wed, 13 Nov 2019 10:40:58 +0800 [thread overview]
Message-ID: <a6bb6739-cc00-cf9f-cd69-6016ce93e054@linux.alibaba.com> (raw)
In-Reply-To: <20191112143844.GB7934@bombadil.infradead.org>
在 2019/11/12 下午10:38, Matthew Wilcox 写道:
> On Tue, Nov 12, 2019 at 10:06:26PM +0800, Alex Shi wrote:
>> Intel 0day report there are performance regression on this patchset.
>> The detailed info points to rcu_read_lock + PROVE_LOCKING which causes
>> queued_spin_lock_slowpath waiting too long time to get lock.
>> Remove rcu_read_lock is safe here since we had a spinlock hold.
> Argh. You have not sent these patches in a properly reviewable form!
> I wasted all that time reviewing the earlier patch in this series only to
> find out that you changed it here. FIX THE PATCH, don't send a fix-patch
> on top of it!
>
Hi Matthew,
Very sorry for your time! The main reasons I use a separate patch since a, Intel 0day asking me to credit their are founding, and I don't know how to give a clearly/elegant explanation for a non-exist regression in a fixed patch. b, this regression is kindly pretty tricky. Maybe it's better saying thanks in version change log of cover-letter?
Anyway, Thanks a lot for your review!
Alex
next prev parent reply other threads:[~2019-11-13 2:41 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-12 14:06 [PATCH v2 0/8] per lruvec lru_lock for memcg Alex Shi
2019-11-12 14:06 ` [PATCH v2 1/8] mm/lru: add per lruvec lock " Alex Shi
2019-11-12 14:06 ` [PATCH v2 2/8] mm/lruvec: add irqsave flags into lruvec struct Alex Shi
2019-11-12 14:06 ` [PATCH v2 3/8] mm/lru: replace pgdat lru_lock with lruvec lock Alex Shi
2019-11-12 14:06 ` [PATCH v2 4/8] mm/lru: only change the lru_lock iff page's lruvec is different Alex Shi
2019-11-12 14:36 ` Matthew Wilcox
2019-11-13 2:26 ` Alex Shi
2019-11-13 13:45 ` Matthew Wilcox
2019-11-14 6:01 ` Alex Shi
2019-11-12 14:06 ` [PATCH v2 5/8] mm/pgdat: remove pgdat lru_lock Alex Shi
2019-11-12 14:06 ` [PATCH v2 6/8] mm/lru: remove rcu_read_lock to fix performance regression Alex Shi
2019-11-12 14:38 ` Matthew Wilcox
2019-11-13 2:40 ` Alex Shi [this message]
2019-11-13 11:40 ` Mel Gorman
2019-11-14 6:02 ` Alex Shi
2019-11-12 14:06 ` [PATCH v2 7/8] mm/lru: likely enhancement Alex Shi
2019-11-12 14:06 ` [PATCH v2 8/8] mm/lru: revise the comments of lru_lock Alex Shi
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