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Thu, 12 Dec 2024 09:22:26 -0800 (PST) Date: Thu, 12 Dec 2024 09:22:18 -0800 From: Johannes Weiner To: Usama Arif Cc: david@redhat.com, akpm@linux-foundation.org, linux-mm@kvack.org, riel@surriel.com, shakeel.butt@linux.dev, roman.gushchin@linux.dev, yuzhao@google.com, npache@redhat.com, baohua@kernel.org, ryan.roberts@arm.com, rppt@kernel.org, willy@infradead.org, cerasuolodomenico@gmail.com, ryncsn@gmail.com, corbet@lwn.net, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH] mm: convert partially_mapped set/clear operations to be atomic Message-ID: <20241212172218.GA19302@cmpxchg.org> References: <20241212135447.3530047-1-usamaarif642@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@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: <20241212135447.3530047-1-usamaarif642@gmail.com> On Thu, Dec 12, 2024 at 01:54:47PM +0000, Usama Arif wrote: > Other page flags in the 2nd page, like PG_hwpoison and > PG_anon_exclusive can get modified concurrently. Hence, > partially_mapped flags need to be changed atomically. Can you please include a description of possible consequences if this happens? I realize this was spotted through review, but it's still important to break down how this might impact users. > Fixes: 8422acdc97ed ("mm: introduce a pageflag for partially mapped folios") This is in an alreaady released kernel. Do we need this: Cc: stable@vger.kernel.org > Reported-by: David Hildenbrand Link: https://lore.kernel.org/all/e53b04ad-1827-43a2-a1ab-864c7efecf6e@redhat.com/ > Signed-off-by: Usama Arif Acked-by: Johannes Weiner