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Tue, 28 Nov 2023 14:45:12 -0800 (PST) Received: from google.com ([2620:0:1000:8411:8fd0:78d2:c604:3ac8]) by smtp.gmail.com with ESMTPSA id f11-20020a170902ce8b00b001cfb971edf3sm6679898plg.8.2023.11.28.14.45.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Nov 2023 14:45:11 -0800 (PST) Date: Tue, 28 Nov 2023 14:45:09 -0800 From: Minchan Kim To: Michal Hocko Cc: "Huang, Ying" , Yosry Ahmed , Liu Shixin , Yu Zhao , Andrew Morton , Sachin Sant , Johannes Weiner , Kefeng Wang , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v10] mm: vmscan: try to reclaim swapcache pages if no swap space Message-ID: References: <87msv58068.fsf@yhuang6-desk2.ccr.corp.intel.com> <87h6l77wl5.fsf@yhuang6-desk2.ccr.corp.intel.com> <87r0ka64v9.fsf@yhuang6-desk2.ccr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: AC262180018 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: a1beeiwfhmzhjsj6fbsxochy5ht3c6qk X-HE-Tag: 1701211513-273586 X-HE-Meta: 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 7/4pzvDW 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 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: List-Subscribe: List-Unsubscribe: On Tue, Nov 28, 2023 at 11:16:04AM +0100, Michal Hocko wrote: > On Tue 28-11-23 09:31:06, Huang, Ying wrote: > > Michal Hocko writes: > [...] > > > Right. On the other hand we could be more aggressive when dropping the > > > swapcache. Is there any actual reason why we cannot try to folio_free_swap > > > even when mem_cgroup_swap_full == F? > > > > If there are plenty free space in swap device, why not take advantage of > > it? > > Maybe a stupid question but what is the advantage of keeping around in > the swap cache? If the page is shared, we avoids addtional IO to bring them back so swap cache. If the page is still clean on reclaim moment since swap-in, VM doesn't need to write them out to the swap disk since original data is already there.