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Mon, 26 Oct 2026 12:35:53 +0000 X-Mizu-Trace-ID: 7e1874fcba217f36 X-Migadu-Flow: FLOW_OUT Message-ID: <67e0c2ce-c763-4705-a965-1ca84898e438@linux.dev> Date: Mon, 26 Oct 2026 20:35:39 +0800 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/1] khugepaged: fix readahead lock inversion in collapse_file() To: "David Hildenbrand (Arm)" , Baolin Wang Cc: akpm@linux-foundation.org, ziy@nvidia.com, liam@infradead.org, nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, usama.arif@linux.dev, kas@kernel.org, jack@suse.cz, djwong@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, hch@lst.de, syzbot+16bf7cd0ebeb1de93aa5@syzkaller.appspotmail.com, ngocthang2710.1999@gmail.com, willy@infradead.org, rppt@kernel.org, ljs@kernel.org, Pedro Falcato References: <20261016065920.4153-1-lance.yang@linux.dev> <27e5aadc-2d68-428f-a958-308e4a75c058@linux.alibaba.com> <6a005d89-df5b-4524-a4b9-c637cb15f1ee@linux.alibaba.com> <3be96a1c-7cfb-4cd0-a4fb-16209494d041@kernel.org> Content-Language: en-US From: Lance Yang In-Reply-To: <3be96a1c-7cfb-4cd0-a4fb-16209494d041@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 7E147180005 X-Stat-Signature: nn3jtmyxtf51acpwfh5g1uw4doowghwk X-Rspam-User: X-Spam-Status: No, score=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=4.0.1 X-HE-Tag: 1793018155-226224 X-HE-Meta: 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 wDvYq9Pf CnlP9azhxJdSsylpwJhTlGh91+kuN5gHauJwNdJQPvFNnKLjuu0oL/E4Rh5vbohyerC5Sq4amQ8Sa3aF1OLPq54emBwweFbkoiXmxYf3iQ1r2Je5w9/+J7jSk1ErIam98qaWOmauzySPYWn2vj1SzPvHYt43xrk9GLK3K/ChIACOQ24gjzLmGtDOdIpoAcR2DHl2kvQCmz69nySo0gG0HHFqVdvgbWkLBzl1tBEhw/Mr7WZaLUjIfCFxkVFJI0EGNP4841JMgkYvIoEDkTxZZk8xFDVB4HdcBcNMw5n75HZFOOpc3I16WmNzrr4l+3SzbEUir9qIKn5R2SH+YIvOsnendvMlLQ5thY7wGtCFg64qd3wnMCCl/RKYfrvQo92RBVqa9P9MR6ID+5KfvKls1eCyZ9fpoQkcEcaqlYDp44HjJxlqWPoidHJzv25CeQCZ6thOFf3z13lRKlMc= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 2026/10/26 19:26, David Hildenbrand (Arm) wrote: > On 10/18/26 04:47, Baolin Wang wrote: >> >> >> On 10/17/26 3:41 PM, Lance Yang wrote: >>> >>> >>> On 2026/10/17 13:43, Baolin Wang wrote: >>>> >>>> >>>> >>>> OK. >>>> >>>> >>>> Sounds good. >>>> >>>> >>>> But why not add RA logic in collapse_pmd(), as we do for >>>> SCAN_PAGE_DIRTY_OR_WRITEBACK? There's already retry logic there, and this >>>> would also simplify the long collapse_file(). >>> >>> That would be cleaner, yeah. Some older stable trees don't have that >>> outer retry loop, though ... I'd prefer to get the fix backported first, >>> then move the RA/retry logic out in a follow-up, wdyt? >> >> IIRC, the approach to bug fixes is to fix bugs properly and cleanly for >> upstream, without being constrained by backporting requirements. >> >> Anyway, I don't have a strong opinion on this. Let's also see what David prefers. > > Let's get this fixed in a acceptable way in a reasonable timeframe; it's been > broken for too long. ... and follow up with bigger cleanups later. > > @Lance is this version good to review for that purpose or are you planning a resend? Right, as for the bigger cleanup, that can come later. Will resend the current version as-is :)