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From:   David Laight <David.Laight@ACULAB.COM>
To:     'Matthew Wilcox' <willy@infradead.org>,
        Shaokun Zhang <zhangshaokun@hisilicon.com>
CC:     "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Yuqi Jin <jinyuqi@huawei.com>, Will Deacon <will@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>
Subject: RE: [PATCH] fs: Optimized fget to improve performance
Thread-Topic: [PATCH] fs: Optimized fget to improve performance
Thread-Index: AQHWfHA0Q0HraGCxZUqID6ug/Nw0ZqlL69xQ
Date:   Thu, 27 Aug 2020 13:07:33 +0000
Message-ID: <6feef2f0b6ed4df99e66c8325c8e66ae@AcuMS.aculab.com>
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 <20200827123040.GE14765@casper.infradead.org>
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From: Matthew Wilcox
> Sent: 27 August 2020 13:31
> On Thu, Aug 27, 2020 at 06:19:44PM +0800, Shaokun Zhang wrote:
> > From: Yuqi Jin <jinyuqi@huawei.com>
> >
> > It is well known that the performance of atomic_add is better than that of
> > atomic_cmpxchg.
> 
> I don't think that's well-known at all.

Especially since on (probably) every architecture except x86
atomic_add() is implemented using atomic_cmpxchg().

	David

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