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Mon, 30 Mar 2026 12:39:07 -0700 (PDT) Received: from x1.local ([142.189.10.167]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8d027edb7ddsm676852785a.9.2026.03.30.12.39.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Mar 2026 12:39:07 -0700 (PDT) Date: Mon, 30 Mar 2026 15:39:06 -0400 From: Peter Xu To: David Carlier Cc: Andrew Morton , Mike Rapoport , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] mm/userfaultfd: fix wrong likely() hint on mmap_changing check in move_pages() Message-ID: References: <20260328170101.184163-1-devnexen@gmail.com> <20260328170101.184163-2-devnexen@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=utf-8 Content-Disposition: inline In-Reply-To: <20260328170101.184163-2-devnexen@gmail.com> On Sat, Mar 28, 2026 at 05:01:01PM +0000, David Carlier wrote: > The mmap_changing check in move_pages() uses likely() but the condition > being true (concurrent mapping changes during UFFDIO_MOVE) is the > exceptional case, not the common one. All other mmap_changing checks in > the same file correctly use no branch hint or use unlikely(). > > Replace likely() with unlikely() to match the expected branch behavior. > > Signed-off-by: David Carlier Reviewed-by: Peter Xu -- Peter Xu