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From: Chao Yu <yuchao0@huawei.com>
To: David Laight <David.Laight@ACULAB.COM>,
	'Sahitya Tummala' <stummala@codeaurora.org>,
	Jaegeuk Kim <jaegeuk@kernel.org>,
	"linux-f2fs-devel@lists.sourceforge.net" 
	<linux-f2fs-devel@lists.sourceforge.net>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] f2fs: change to use rwsem for cp_mutex
Date: Tue, 24 Nov 2020 11:12:14 +0800	[thread overview]
Message-ID: <a1b9a134-97a8-6fb7-2fdc-d4de91dff849@huawei.com> (raw)
In-Reply-To: <7f5213fb9b334d1290f019ab8ed6ee71@AcuMS.aculab.com>

On 2020/11/24 1:05, David Laight wrote:
> From: Sahitya Tummala
>> Sent: 23 November 2020 05:29
>>
>> Use rwsem to ensure serialization of the callers and to avoid
>> starvation of high priority tasks, when the system is under
>> heavy IO workload.
> 
> I can't see any read lock requests.
> 
> So why the change?

Hi David,

You can check the context of this patch in below link:

https://lore.kernel.org/linux-f2fs-devel/8e094021b958f9fe01df1183a2677882@codeaurora.org/T/#t

BTW, the root cause here is that mutex lock won't serialize callers, so there
could be potential starvation problem when this lock is always grabbed by high
priority tasks.

Thanks,

  reply	other threads:[~2020-11-24  3:12 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-23  5:28 Sahitya Tummala
2020-11-23 17:05 ` David Laight
2020-11-24  3:12   ` Chao Yu [this message]
2020-11-24  9:12     ` David Laight
2020-11-25 13:08       ` Sahitya Tummala
2020-11-24  3:06 ` Chao Yu

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