From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B515D367285 for ; Tue, 12 May 2026 06:34:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778567667; cv=none; b=iseRcN74gA3WrjMy3Fj25zQlpZ4mDnGWBc8leU0DrbQxc7MBWy9ubJ2r3xJm7vNEBaLK2qHcaKVwiKYtr+jvVKonnNoQ77AjvxDs4b81mmkWI0KmlWY7rCiH1mH8Ryfb5QtRnSDUZo9bVR4c1DsL+LOJvZq/7BGrtZHPnsnMHzE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778567667; c=relaxed/simple; bh=2Dtp3nUQYhSh8d8Ve27AoBtFKT+5FmmE8Snx2QeLqYE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Ku4XIoM5b8wMFtA20CRPlpirtDOhCbTEC1zHWSI2X7CUcNlocsCICgGR6WnVYNZWIfZ0Q/AVPEQorwqY4D0qqTFXT9kKONoV+ZCtO55noybtZQ0Rc6pbo4XROzl3tMxN6sRTRT2AI3JU8sMTdo6JTDqKdYx7MkgpBVh8G6kHIbA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WN/hN8op; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WN/hN8op" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 10853C2BCB0; Tue, 12 May 2026 06:34:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778567667; bh=2Dtp3nUQYhSh8d8Ve27AoBtFKT+5FmmE8Snx2QeLqYE=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=WN/hN8opfQE4WzDY0qzDO/2LAWOwpx9SpPVN0H/kYGKO4gkdkG/rzO8Wh+zORALY5 XG/esKrshYv5C1YdL+UGQt6mDKQGpgQoQleYursPSab3D/0sUQqd9UxUty4dQti7Eh 0KbtNvzPG85Ja5LhQj3Zu3BMdUvKrE5lgCQXQ2ikgyWE8JimkIv+eo3P1gUpg3Ugvi hTqNR76cEaOzEHwDfa/TtAf8J3BIjV3FYoWs6cJGcvOIBH6Qe3WcD1Ni0SoKhPwqFY F1euq2tlUE9fH1jayXdWB3b/LOF6FZTjKjhHiinGc+ISsmd3c0fq3160o6sclvAqRM RFGdUfdntKgtg== Message-ID: Date: Tue, 12 May 2026 08:34:17 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/7] Accelerate page migration with batch copying and hardware offload To: "Huang, Ying" 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 References: <20260428155043.39251-2-shivankg@amd.com> <98a16642-35b7-4cf9-9ee2-8de15e877920@kernel.org> <874ikdwe21.fsf@DESKTOP-5N7EMDA> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/12/26 04:35, Huang, Ying wrote: > "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. Wouldn't we still want to process them in batches, only affecting folios in a batch at one point in time, not the whole address space? -- Cheers, David