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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1qsaJb-009qU7-3o; Tue, 17 Oct 2023 03:00:15 +0000 Date: Tue, 17 Oct 2023 04:00:15 +0100 From: Matthew Wilcox To: Kairui Song Cc: linux-mm@kvack.org, Andrew Morton , "Huang, Ying" , linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/swap: avoid a xa load for swapout path Message-ID: References: <20231017011728.37508-1-ryncsn@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231017011728.37508-1-ryncsn@gmail.com> X-Rspamd-Queue-Id: C504B160015 X-Rspam-User: X-Stat-Signature: 9wtb6cbdu8gbkwbtseqhsjwokd6wqjwb X-Rspamd-Server: rspam03 X-HE-Tag: 1697511630-626843 X-HE-Meta: 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 9gwlwog0 haZpxW9i/KjP3UjafqvTbIVIa6nbHOarpqpOSXmbyAzph7mpOVCQC1IIsUkGKdlhdILEXeFHwoAbzZaXUIAJqgnQTWvt7t66Sb9VGeJpwS27TGpgO8Wq0xoWTDk+EDu1EE1741qhE2yBUaoxADY0C8aXrDLsxxcFtpFYLKTze7wCo07B3mbFCYB0vSudIUFoe+MZD X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Oct 17, 2023 at 09:17:28AM +0800, Kairui Song wrote: > From: Kairui Song > > A variable is never used for swapout path (shadowp is NULL) and compiler > is unable to optimize out the unneeded load since it's a function call. > > Signed-off-by: Kairui Song Reviewed-by: Matthew Wilcox (Oracle) Possibly worth adding a reference to 3852f6768ede ("mm/swapcache: support to handle the shadow entries") Not sure it's worth a Fixes:, but that's where it was introduced.