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[80.230.85.71]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-490bc3cc140sm505952095e9.9.2026.06.08.14.16.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 08 Jun 2026 14:16:58 -0700 (PDT) Date: Mon, 8 Jun 2026 17:16:53 -0400 From: "Michael S. Tsirkin" To: Gregory Price Cc: Lorenzo Stoakes , linux-kernel@vger.kernel.org, "David Hildenbrand (Arm)" , Jason Wang , Xuan Zhuo , Eugenio =?iso-8859-1?Q?P=E9rez?= , Muchun Song , Oscar Salvador , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Hugh Dickins , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Ying Huang , Alistair Popple , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo , Axel Rasmussen , Yuanchu Xie , Wei Xu , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , virtualization@lists.linux.dev, linux-mm@kvack.org, Andrea Arcangeli Subject: Re: [PATCH v10 12/37] mm: use folio_zero_user for user pages in post_alloc_hook Message-ID: <20260608170646-mutt-send-email-mst@kernel.org> References: <20260608154354-mutt-send-email-mst@kernel.org> <20260608161810-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: Wsna51HcyThFG1mUpXcHGI-jIesHQw6maRvA38u_sBI_1780953420 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 9551D120005 X-Stat-Signature: kcntjod5uhhefnzcjfpjhs9iicsxt9cg X-HE-Tag: 1780953427-558846 X-HE-Meta: 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 OUbszC2N rmAz/2+GOzJcO1cJJTDklvs+qjMQUSNJt4f5W3nnDkdTs+LyN/SzpwbsVgg2g2+dwLQUGg9McCPyWjuepy+H/dELbyynvd9GQeahZCcaEzncxNw3+UNIso4anljypCfCJYOQjNYDg9iVoNXWY/ajsD92V5/dD9aEaiO/igMfsgsXEG6iRA3eu+OnfjXzDA47q9xzMPdnTua/hkvjDTpkik0aerIF6Ic9DSONPZwxoup04Xwb24x4K2rFWq5mpUPPgY/M6I6TxmJ0u7jiI5wEyuLonFFYrYqTlzG7fgC0XdM2sfIMHead/Ph/tvWePrvcafp942uuCuZTOdFPFKSKSOTkn1MSMEoW/30X+ZhTzJZRmdcORN7QDA9bMhJlWHS+tDCJR7V0MUCfmAvag9fRMwodFcQ89NQSCFe/i Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Jun 08, 2026 at 04:53:14PM -0400, Gregory Price wrote: > On Mon, Jun 08, 2026 at 04:30:46PM -0400, Michael S. Tsirkin wrote: > > > > > > Please consider that this is arguably the most fundamental interface in > > > in all of mm/. All we're doing is going through the process of figuring > > > out what changes here are reasonable while trying to meet your goal. > > > > > > ~Gregory > > > > I don't mind discarding all of this and doing something else completely, > > but I dislike it that multiple people are apparently now angry that I > > I wouldn't say anyone is angry, I think most folks are tripping on the > complexity of the set - which has increased (at the request of others). > > > don't address all the contradictory comments at the same time. > > Such is life in mm/ :] - it's hard to known the entire state machine, > and sometimes the contradictions aren't even wrong. > > > I thought just sending a patchset to show how the result looks like > > is easier than arguing about architecture, and would be helpful. > > > > Notice: When folks argue implementation, they largely agree the > end goal is useful. I haven't seen anyone say your problem isn't > real or that it shouldn't be addressed - just opinions on a particular > path forward (which is utterly normal here). > > Getting the right incantation of an API is really hard when the > API being changes is something that underpins the entire kernel. > > > I'm not pushing any of the mm rework, I was asked to do it, > > myself I just want the ridiculously effective optimization in there. > > > > As Lorenzo, David, and Matthew have said, the focus of the patch set > does seem to have become unweildy (in part at the request of folks > asking something be done differently). > > What needs to be done now is to break it up into some pull-ahead > sets that are easier to review. Having a brief RFC doc that lays out > the set of patches might help clarify the confusion going on here, > especially as new folks come in to ask "What's all this about?". > > As a start: > > 1) the user_addr and zeroing piece seems like a discrete > improvement worthy of its own set - aside from end goal. > > This is needed by your patch set, but was requested to > try to push us towards a more reasonable pattern for > folio_zero_user(). What I worry about is people can't agree what api they want. Simply not being an mm maintainer, I don't really have the perspective of what changes are envisioned down the road and so what api makes sense for you guys. I don't mind trying all kind of approaches, but it seems to be past the point where people feel it's costing too much of their time with all of these revisions. > 2) There are a handful of patches that seem able to pull-ahead > (some of the mempolicy stuff), either as prep work for #1 or > just on their own. > > Some of these patches seem like latent bugs that aren't hit by > current users, but do seem to be doing something subtly wrong? Right. > 3) the final virtio piece seems like it should be entirely separate > once the core pieces are done. > > It's not uncommon for core changes like this to take multiple prepatory > sets over many major versions before the final feature lands. > > ~Gregory