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Received: from DESKTOP-5N7EMDA(mailfrom:ying.huang@linux.alibaba.com fp:SMTPD_---0X2op7A9_1778553302 cluster:ay36) by smtp.aliyun-inc.com; Tue, 12 May 2026 10:35:03 +0800 From: "Huang, Ying" To: "David Hildenbrand (Arm)" Cc: Shivank Garg , akpm@linux-foundation.org, kinseyho@google.com, weixugc@google.com, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, willy@infradead.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net, apopple@nvidia.com, dave@stgolabs.net, Jonathan.Cameron@huawei.com, rkodsara@amd.com, vkoul@kernel.org, bharata@amd.com, sj@kernel.org, rientjes@google.com, xuezhengchu@huawei.com, yiannis@zptcorp.com, dave.hansen@intel.com, hannes@cmpxchg.org, jhubbard@nvidia.com, peterx@redhat.com, riel@surriel.com, shakeel.butt@linux.dev, stalexan@redhat.com, tj@kernel.org, nifan.cxl@gmail.com, jic23@kernel.org, aneesh.kumar@kernel.org, nathan.lynch@amd.com, Frank.li@nxp.com, djbw@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 0/7] Accelerate page migration with batch copying and hardware offload In-Reply-To: <98a16642-35b7-4cf9-9ee2-8de15e877920@kernel.org> (David Hildenbrand's message of "Mon, 11 May 2026 17:53:24 +0200") References: <20260428155043.39251-2-shivankg@amd.com> <98a16642-35b7-4cf9-9ee2-8de15e877920@kernel.org> Date: Tue, 12 May 2026 10:35:02 +0800 Message-ID: <874ikdwe21.fsf@DESKTOP-5N7EMDA> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 7E7F940009 X-Stat-Signature: ykatxtzrui3qr9w56gpfbtctn1r43tfq X-HE-Tag: 1778553312-905693 X-HE-Meta: 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 NxWF6JDn YtV+wPPYj0cWwqDlzQ8ou8efYooyPxzht15JcleuA2smBbQ1PpGL03Dnc5dI1MxISILM/SCrH1c2d9swm2ewPGHWf26r7Mb2r2PQja/xV0cpeq2w+OELEmj7+5I+H7M8A75jipD7ZqLI+O5rLYTJdlOyW4l5nm1E3u+mezKt3Tm01thM0aFDYZX49iqUX2fFFq+Bbub5WLKBJgzACiQ3WvcQ+p3uoh1Et8Qmcq0YkPRH7si2rYi7SYxcoM1OCvkbjt6+T5Fr3plAogWFog10ztFBmy52iKXANkBgjFh63pUnZ2WrJspnXvrOVKvHJ0uw8GuUgiPwxiF4c9l4qGPDkSoXZoHX3gI9yBhASsopVAdDyrUkGJXJ8ZxOdZw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: "David Hildenbrand (Arm)" writes: > On 4/28/26 17:50, Shivank Garg wrote: >> This is the fifth RFC of the patchset to enhance page migration by [snip] > >> >> 3. Per-caller offload selection: Today eligibility is by migrate_reason >> only. Some are latency-tolerant, others may be not. Is reason the >> right granularity, or do we want a per-caller hint? > > Isn't it sufficient to just do it based on the #folios or sth like that? > > If someone migrates a handful of folios, latency is likely more important (and > batching less beneficial). > > I'd assume when migrating many folios, batching could just always be done. Or > what's the concern? IIUC, for callers like migrate_pages syscall, it's possible that almost all folios of a process are passed to migrate_pages(). However, I think that we still need to keep the folio inaccessible time reasonable. [snip] --- Best Regards, Huang, Ying