From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk1-f180.google.com (mail-qk1-f180.google.com [209.85.222.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6045635CB95 for ; Thu, 23 Jul 2026 03:25:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784777125; cv=none; b=AGEkhE2VTQepjYmalUyuKnqOQ0evYQWHA2NmesF3HPORLAvUDxQTbmcLwwPV6dzppwiXPo6scjzejPUo8SGl/rnkMWjcWPN96xQ/01fWTp5HQDhAPV4HCO1WRc0UO0mRuG3rOiBJDu98psNecir/+wnIHnn0A1X9xdbIw2nZQnA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784777125; c=relaxed/simple; bh=gfT0G2h32Mgahppc0W5ji5WK8maIODJ9zFl+mqtZVuU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=aBLmhHtTdGqyFhWTwTF63TWSso+9RLUzo/VVkBJUE/ElVPs+16owzEmf7J+B2XH0VnCjV/+0IugtzzGsIGOBPvVWcH0jNa+Ax58quo0/hoXHR3dpRDBhZBpU3XUoBPwVQTawUfheIwJ0DHCkyWgzp4/r9llLTY8kppVujlKUe5Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net; spf=pass smtp.mailfrom=gourry.net; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b=S5k+/km/; arc=none smtp.client-ip=209.85.222.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gourry.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b="S5k+/km/" Received: by mail-qk1-f180.google.com with SMTP id af79cd13be357-92ed19f4d60so335285a.0 for ; Wed, 22 Jul 2026 20:25:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gourry.net; s=google; t=1784777122; x=1785381922; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=Kd13UizLWaDa1rNXvY/PJ0N43yZ3Vd9IZn7XTlTXtfM=; b=S5k+/km/W3hDbRibPNpOoB80+fMcI4MbaVCKgEaeGawR+FQWl9kNV2iUGzMuP5o587 /iaVfV9Jd+R4VNTdxnjkkgdz20NTR/Eu8b80hXADBRflMrWslncYyJ3SvD3gwvv5ngtC ziCEhyqOck9EWcwsKAG1K0Fzc1bP7k6aIwfto2hePcg8FFQ5b1ILjIFtAueuSZJkiFL5 nYdguJXw90nDowVcfKGttiFdnF1n59L9sXbcemc/huQrcwmkhJfTVLcf0o+RBBzMGJDB vgBWGT12txaO7gCP8wM5mTntpmBdTwxcjXyxbZfzrXl9J3a1TwC6EBaOEEphMqOrCOjK FmPQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784777122; x=1785381922; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=Kd13UizLWaDa1rNXvY/PJ0N43yZ3Vd9IZn7XTlTXtfM=; b=s5fkl3D2u/hTZeIEBOhcqRmOj08+U4+qO9Ifxpgg2PfZRTUbMUmORkSj+6D44DPit4 oVoLux7qygZE/FWGM46VKDEj2ermhJBMU+eVctrK/UF1GhLHVPxT9Zj7Huapc8OmBv/3 3eoLi+S5BQwH2feseJD9MVO89+/4M5XBXqRvHh3RZ9Kx4cWCAaB8oAYuGSVtHjWxmClS DRs5GdLjWDpARsPexVxOTTv8IbztyI351G9EaIEqko72eJauyWx04oLtqQCXdRnLu6+H 0w8ukm/gpGRbOZVkReNzMgcNPkc6b/CxpQI8Hgrdv1jKjpvpow8cGI8r2mjAgjQmoUir VTaQ== X-Forwarded-Encrypted: i=1; AHgh+RrY7IsQewQibi+y5FxSHGcf7Cz3XPCUvg2nR8r4pq643Oc4UTQRa3q98tBw8nBXN5J/M35DORcoU/zr9EVG@vger.kernel.org X-Gm-Message-State: AOJu0Yw5OT1NxKSE/QYrgw8sXdV4Gzl/BpV2mG2ldG41x1c7MMCQGi0z c/LVOdG47+PLzVX4q3xXHOxgTuPGWdbIOEXrMf6i4EOBk00yfLeu+lz0shuBgIgYzfk= X-Gm-Gg: AR+sD11tWKfYq1e2JyRz5e5C3OFOiIZNNAJrPVtq2W1g4u14qFuFy1/GpN3M1f6Zpyz 61cRjfEZRlprMWXNeFgYtHu/OSt7UZ7AVI31gHW1vavSi3GxLtSlX0wAotKDAIhEoOROFDdgNyG WX047oCzWUXnwsskFkVtxkq+XVE6zUj9EEx85ycRDuAbBcnDS/ft0jtRPghwO9yyu9+fwlw+Szs kgLdHTK9YKpGvmC6f86Z3jYiS825mZCq9vIetJcRIT41AA+ZzGqI44PC69wBlLfN/n4DncyLOHn ha2gmOK+MPArGGetI3FjPXAFaETe7KD7DHDkuInJEzO8SqhdmYaFDvYe64V0vXvWJgNtT2hY2En Zm3ZwJrGhps8qwEW8f4jOp0EQS5aElCN02jwM9ZQ1PcNsAxCLyKsAwv6/bUG9eFO1DTmHKdpFKU /qJnzaUNuQnQ0yATA15QjPagqACS7e8nru/dYb1zNGKQKptErae5EA2pyjHsl0s9PHjWeW X-Received: by 2002:a05:620a:808c:b0:92b:67e6:4b79 with SMTP id af79cd13be357-931048880c8mr90170685a.35.1784777122066; Wed, 22 Jul 2026 20:25:22 -0700 (PDT) Received: from gourry-fedora-PF4VCD3F (pool-173-79-60-52.washdc.fios.verizon.net. [173.79.60.52]) by smtp.gmail.com with ESMTPSA id af79cd13be357-931062c4ea8sm34465885a.28.2026.07.22.20.25.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Jul 2026 20:25:21 -0700 (PDT) Date: Wed, 22 Jul 2026 23:25:15 -0400 From: Gregory Price To: SJ Park Cc: arun.george@samsung.com, balbirs@nvidia.com, brendan.jackman@linux.dev, yuzenghui@huawei.com, apopple@nvidia.com, alucerop@amd.com, matthew.brost@intel.com, akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, corbet@lwn.net, skhan@linuxfoundation.org, gregkh@linuxfoundation.org, rafael@kernel.org, dakr@kernel.org, djbw@kernel.org, vishal.l.verma@intel.com, dave.jiang@intel.com, alison.schofield@intel.com, osandov@osandov.com, jannh@google.com, pfalcato@suse.de, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, pbonzini@redhat.com, osalvador@suse.de, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, ying.huang@linux.alibaba.com, kasong@tencent.com, qi.zheng@linux.dev, shakeel.butt@linux.dev, baohua@kernel.org, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, yury.norov@gmail.com, linux@rasmusvillemoes.dk, longman@redhat.com, ridong.chen@linux.dev, tj@kernel.org, mkoutny@suse.com, jgg@ziepe.ca, jhubbard@nvidia.com, peterx@redhat.com, baolin.wang@linux.alibaba.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, lance.yang@linux.dev, usama.arif@linux.dev, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, roman.gushchin@linux.dev, muchun.song@linux.dev, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, driver-core@lists.linux.dev, nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org, linux-debuggers@vger.kernel.org, linux-fsdevel@vger.kernel.org, kvm@vger.kernel.org, cgroups@vger.kernel.org, damon@lists.linux.dev, linux-kselftest@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH v5 14/36] mm/damon: skip private node memory in DAMON migration and pageout Message-ID: References: <20260723001943.95854-1-sj@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260723001943.95854-1-sj@kernel.org> On Wed, Jul 22, 2026 at 05:19:42PM -0700, SJ Park wrote: > On Wed, 22 Jul 2026 08:16:56 -0400 Gregory Price wrote: > > > > "by default". Does that mean it could be reclaimable in some situations? If > > > so, could we check if it is reclaimable? > > > > > > > See the damon changes in: > > > > https://lore.kernel.org/linux-mm/al-pkvmgIxGu3LzM@gourry-fedora-PF4VCD3F/T/#mfb99303c85dd9d4c3f58832dc28fc55583a7217a > > Summarizing what you want to say, quoting something from the patch, or at least > calling it "26th patch of this series" would have made reviewing much easier. > Cc-ing damon@ for only patches that toucing DAMON source files and the cover > letter of the series could also be helpful. Please consider doing some of > these for future replies. > I have been very much discouraged from this kind of trimming because it removes the context of the series from the individual patches - making it even more confusing. But I understand, I will try to remember to do this for you. > So, I understand later patches will make it optionally reclaimable and update > this restriction by the 26th patch? That sounds fair. But, could we drop "by > default" from the above comment for reducing the confusion? Yes, but you bring up a good point - I think this two-step process is actually poor form and that I need to redo it. Maybe this can be redone as node states (features?) such as: N_MEMORY_RECLAIMABLE N_MEMORY_DEMOTABLE N_MEMORY_TIERABLE so these damon changes will forego this confusing intermediate step of: if (folio_is_private_node(folio)) and go straight to if (node_is_reclaimable(folio_nid(folio))) In the first patch - without ever having to revisit damon again. > > > > Technically there is nothing in migration core to prevent migration > > operations, it's done on a service basis - hotunplug, reclaim/demotion, > > user numa (mbind, migrate/move_pages) etc. > > > > Operations on private nodes/private node folioes are refused if the > > capability bit is not set. > > I haven't had a chance to read the entire series, sorry about that. So, do you > mean the above blocking is not really needed, or that will conditionally be > allowed by another later patch? > I will reduce this all to a single patch in v6, I see where things can be improved now based on a few pieces of feedback. Thanks SJ! ~Gregory