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b=Mic0UrNqqNfV55zdjXUqwQrg9u7c13NFfUwM6GjdKIItNtcBY3kuGQ1pAkLONlASN jORmduxma2Gej9GpBK7kjYfwebJhZlx7ATpi/8H9PHXaHmt/i0/gwTJwoZDxxt//YF g1Gs8AuEfEuva8i2Vk6qYgW2xG/GJSbuzgLMnH7HbrTz9EBzev1Y7bX3hyoZpdF61r ZG/ugAZG/0c67G0bXslH/6L71VmliJ3afB/cs/NWz9VzEbCDX88tTMSPVPTmzECcHM tcgs6sWfhYGxyefuFkY+29YPca/u0uodDzLNBl+hqh5HAiwo1ZR53p4WTkJA8nlbZq t+8vF8SHBIquQ== Date: Tue, 31 Mar 2026 14:42:54 +0300 From: Mike Rapoport To: David Carlier Cc: Andrew Morton , Peter Xu , 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260328170101.184163-2-devnexen@gmail.com> X-Stat-Signature: 7be58zh7w3ajq1n9fjzd5zygk33f3jg7 X-Rspamd-Queue-Id: 117F120003 X-Rspam-User: X-Rspamd-Server: rspam03 X-HE-Tag: 1774957380-357341 X-HE-Meta: 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 ZVz5JG/5 S2kQCX7JnX7ePrYxuRLL5RN/3+V0wxXexvLOCDy9ujlmwOL8srXByRanrTKu0ScZt1Fjdaf8EyXhZ6NKBpvcG5kz6br3gpkbsHzsJcBiv4tJtnF7pQVfxlEc+eJMET17dcdMPbzQjyjygjSyYaGcL47AXirP18J80eOWO4g84nCRYH9Jh6aKsq32hU/UA0mzhA2tlsmCeOTzYVebFjUfO9ousQWcknGt0Unybk2ITdL2GkAt95rIelc1gPuckaXGdddQoK/UwV88TMEWB+z93u46k+SS0jxDBw90zeICAXix3vJgTO9yXnFyOZ7JorLDkl+1ekyIZYVHwlmX/eTcBMxchAg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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: Mike Rapoport (Microsoft) > --- > mm/userfaultfd.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > -- Sincerely yours, Mike.