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b=OyHe/4xAP6WCorugyhRh2YGYy1BO8A93QVK/QxBl2JzDgugFa9HrveviyxJbzlrWf N33EqbM2ND75BtjehLURhzxhyjHyl6NniMAEsJfnDZYeTbAg3hK+IvI3x0YjG4vo4E n+yqhpr8ii7uWk60fU5cm/53Qe9WInE/L2P/WP2PE5NuZdk1NKioHg/186/EFHaLJQ QJA1prI/67wzJVaDtoSH4dTgG+vmi/JAJ+74NvRX8dmeMW6VdBZA/QHDC4jYJnMqfU FvOAocq2S8xNemSBNQtWykHxyrmVAymLc2QykuIICKnMqKWn3A073a8l7gcEpSJiVL J/Kct1lCTTz1g== Message-ID: <3c73fe54-68d8-41f3-8f9f-06c4a1891e01@kernel.org> Date: Tue, 27 Oct 2026 13:53:34 +0100 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5] mm: memory: fix truncation removing mapped folios To: Baolin Wang , akpm@linux-foundation.org Cc: ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, qi.zheng@linux.dev, jack@suse.cz, pfalcato@suse.de, ayushr@modal.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <2ba579e8-06fb-41f5-9eb2-f02b2aabe29b@kernel.org> <87e32afd-75de-4407-8f0c-fb70b40d5eca@linux.alibaba.com> <81ee2c92-f342-4f7f-aacd-d9558e67a980@kernel.org> <4880d4ff-8486-4e22-9923-bd4f2407b1cb@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 88EA62000A X-Stat-Signature: rx8tx3zo89a8p6immc81kjssacraagut X-Spam-Status: No, score=-7.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, 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-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1793105621-431720 X-HE-Meta: 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 +YZuIsIL Zq4L2IiFyAaZAzNJC9t+ZVnpt2i/6YjgfachNLwUz5+Kf1JU5gIGyR7u+7yjz4HmrQKA40DaPa9M/7L9oGoS0bC33vLjkb3yREqnI8bVualruSL7bHCKNgwdMZC35YPfXHwkurHP9YNakyrr5BVffVEEVQ1h9+XKIMKXOfy1J9LMUTMJsxgXAQ9/c+GCvoxDU050RZcM5d/QPtNBy/3nGZFTwQwL+sgOipFGw4j9yJB2r7iaq435rzLzDjS/yd20EI/Gf 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 10/27/26 13:50, Baolin Wang wrote: > > > On 10/27/26 6:55 PM, David Hildenbrand (Arm) wrote: >> On 10/27/26 11:35, Baolin Wang wrote: >>> >>> >>> >>> Sure. >>> >>> >>> IMHO, I'm not a big fan of adding two pmd_none() checks just to avoid an >>> uncommon concurrent sync. >> >> It's what we already had. We had to: one for handling pmd_none() directly and >> one for handling zapping while splitting (file THPs). >> >> We just managed to let the second also handle the final piece of the former. >> >> Anyhow, let's get this fixed. >> >> If you think the code is clearer your way (where I disagree) > > Fair enough. Though I have a different taste, I'd still like to make the > maintainer happy. Don't worry, it's hard to make me unhappy :) (just a bit overloaded right now) > I'll send out v6 tomorrow following your suggestion. > That looks good. Are you planning on following up with the memory barrier optimization for smaller folios? I hope below doesn't end up in some performance degradation. -- Cheers, David