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h=Date:From:To:Cc:Subject:References:In-Reply-To; b=nmtVWfiMTmNf6D+IX+7K3ePXqNYLegK8TT6JQ1uNfPCg1/lZNl1hdy2I9ZyVlBdqc XUGbbL3VR3ElWJPiiOgM97mnVnP0BqU2QD0SV2hFa2Eib8ci6/5rLW9rls6OtN4nk3 uIGXqzOAXE8tKcd13d5ANdSxe7aDhjCbF1akk4opPo99gdBrvU8MtwuU7j2b1g+TXX fqYRTf5visUjVSFpVAG9EwuqGwtJkX1CPP6lnk6zNbZpnGVVigaaOGODi3dYe5/kPY t5yaYxKVlUmVmfPF7Mr+6NnK8zrgsv5stXOUaO6dCmRV40JC5G6bXFk3A4WQ5NnPEz s9pYjIfB/RoEQ== Date: Tue, 26 May 2026 03:47:46 +0000 From: Jaegeuk Kim To: Matthew Wilcox Cc: Theodore Tso , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, Christoph Hellwig , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Akilesh Kailash , Christian Brauner Subject: Re: [f2fs-dev] [PATCH v2] f2fs: another way to set large folio by remembering inode number Message-ID: References: <20260521155748.GA79343@macsyma-wired.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Queue-Id: 1ADBF20003 X-Rspamd-Server: rspam03 X-Stat-Signature: zyd5o5p4immrfso3xxxoxc7aq8z58gmz X-HE-Tag: 1779767268-58825 X-HE-Meta: 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 NdlZfPAd 467eSfaqKKpmoNMz975h/idj9v87X/jPVNlzR0yb5IEko41oOiVJoOc9ZRPT2MGQ1Xo17w20KFyYY/Uzz4uh+rqJ6daN2qosSeHlNEg53gzA4Qjp+SgyDhnoVjGkbr0Pv5D8QBCGvrnCEkQXKgTxI8BR6Xw/qHCptJ+1SaB5Qt7WgjoPd1LlhUTIjv12T6d9LJoFi4UaeCA5jziFjSmdEncA1z+LaaDfq6BHpmpCVPlPbl8QGwH38hfO4m7POrI0ptmPwzZHKEslv7J5oMoWahqxWRnvCeJ3AVHvY/gjDkT88zIU34GJna82/Hw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 05/26, Matthew Wilcox wrote: > On Tue, May 26, 2026 at 01:21:33AM +0000, Jaegeuk Kim wrote: > > On 05/24, Christoph Hellwig wrote: > > > On Fri, May 22, 2026 at 02:04:59PM +0000, Jaegeuk Kim wrote: > > > > This was a quick buddyinfo right after booting the device. > > > > > > > > Before: > > > > Node 0, zone Normal 22684 42284 28704 16901 9515 4566 1854 673 181 36 758 > > > > > > > > After disabling EROFS large folio: > > > > Node 0, zone Normal 8486 4732 2175 1161 697 272 82 19 3 1 856 > > > > > > And what are you trying to say us with that? > > > > This means, high-order pages were used up by EROFS which sets large folio by > > default. So, I wanted to say the concern was based on actual data which was what > > Mattew asked. > > This isn't that though. What you actually need is to show that high order > allocations are _failing_. The MM is far more complicated than you seem > to understand. There isn't a fixed number of large folios available; > when we try to allocate memory, we do reclaim. And if there's large > folios on the LRU list, you'll get them. > > If what you want is large folios readily available, then what you want > is large folios used _everywhere_ because then they're easy to get! > If there's small folios in use, you need to reclaim a lot of memory in > order to reassemble large folios (it's the birthday paradox, similar to > the hash collision problem). Thanks for the feedback. Actually, I tried to do compact_memory before doing read() for AI loading, but I got complaints where it took hundreds milliseconds to run that compact_memory. Is there a good way to secure high-order pages before that read()? It was quite hard to project when it will happen. > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel