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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pXk04-002SXj-Dc; Thu, 02 Mar 2023 14:33:40 +0000 Date: Thu, 2 Mar 2023 14:33:40 +0000 From: Matthew Wilcox To: David Hildenbrand Cc: "Yin, Fengwei" , "akpm@linux-foundation.org" , "linux-mm@kvack.org" , "mike.kravetz@oracle.com" , "sidhartha.kumar@oracle.com" , "naoya.horiguchi@nec.com" , "chu, jane" Subject: Re: [PATCH v2 0/5] batched remove rmap in try_to_unmap_one() Message-ID: References: <20230228122308.2972219-1-fengwei.yin@intel.com> <20230228122823.eba4f0fa5f7f436a2f8b3a3b@linux-foundation.org> <19263da54b9818332620345bbed69e8ded241e00.camel@intel.com> <604c372c-e474-14a7-dd80-c5197f12564d@redhat.com> <1c6c9d3e-3a7e-4d07-7c7c-9b7c01bcdac6@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 9DED8C0011 X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: zyrx1u1fsjnzncto3d4h41ih3u3xraho X-HE-Tag: 1677767631-854939 X-HE-Meta: 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 DDtf7MNS 91IRDtDbKXABCAAoP4uEoquV2EgS0fh6/ze2PJaX2EY6QGw5xM12wXQDXno8Y5GOnEjFwTB7oTkueK43jEmvpan41JCyj7x3vMswa3mif2AgrCMBrX+/wcuU6EyKgggt/V4JPflZjZK15dx45890qLg6xEaTiBhGu82GGvHO9aWfWkkmS3Uzxb7Wuzxl4Gd71FGDMNL+Qzgb+XpA3IpW7QD/0rNsUjUyFBHhbN66QoxqbpnDrmw8dXAiCBQ== 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 Thu, Mar 02, 2023 at 03:23:46PM +0100, David Hildenbrand wrote: > If no workload/benchmark is affected (or simply corner cases where nobody > cares about performance), I hope you understand that it's hard to argue why > we should care about such an optimization then. In order to solve the mapcount problem, we're going to want to unmap the entire folio in one call, instead of unmapping each page in it individually and checking each time whether there are any remaining pages from this folio still mapped.