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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
Date: Thu, 27 Aug 2020 13:07:33 +0000	[thread overview]
Message-ID: <6feef2f0b6ed4df99e66c8325c8e66ae@AcuMS.aculab.com> (raw)
In-Reply-To: <20200827123040.GE14765@casper.infradead.org>

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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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)


  reply	other threads:[~2020-08-27 14:56 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-27 10:19 Shaokun Zhang
2020-08-27 12:30 ` Matthew Wilcox
2020-08-27 13:07   ` David Laight [this message]
2020-08-27 14:28 ` [NAK] " Al Viro
2020-08-28 11:04   ` Will Deacon
2020-08-31  1:43   ` Shaokun Zhang
2020-08-31  3:21     ` Al Viro
2020-09-01  9:29       ` David Laight

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