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b=Byq60xxiXtkUaPao9CHLMM6/ZD4JUm1Fi51Ys170+hT7Jr9h8MLvsYenIUwL6QCLN /pvKH0udwL+Ie7QkkNcK9vJa2M54GwBOUdm1ShpLMLiN6cXCjc6an8WrE1qnXZKhdD 6liogk84HhVpZdEcYrUxIpAzIjGuochwQdz0SCpA= Date: Thu, 28 Sep 2023 09:38:09 -0700 From: Andrew Morton To: Suren Baghdasaryan Cc: Yang Shi , hughd@google.com, willy@infradead.org, mhocko@suse.com, vbabka@suse.cz, osalvador@suse.de, aquini@redhat.com, kirill@shutemov.name, rientjes@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] mm: mempolicy: keep VMA walk if both MPOL_MF_STRICT and MPOL_MF_MOVE are specified Message-Id: <20230928093809.75de08561b0fa1af03bf4a89@linux-foundation.org> In-Reply-To: References: <20230920223242.3425775-1-yang@os.amperecomputing.com> <20230925084840.af05fefd19a101c71308a8cf@linux-foundation.org> <90fc0e8d-f378-4d6f-5f52-c14583200a2e@os.amperecomputing.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: dmdhwhsc7zf9t1cqdibh1e1m9y6icbca X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 1351C40010 X-Rspam-User: X-HE-Tag: 1695919094-271147 X-HE-Meta: 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 Hlmypv9r h+2WGzOYSgssiC3UpYGpxrmM2nZJxvX7QYZI6aMKcBL0JXdQ4JKpwGD12YKEf6H39zzWRKwd9Wsrj+wQ1AOevY4CvJkjA9/YV9m/mHDiQ+vwJqA9iFe7lmhjp1TYpc46oKDNK0AzBgTVY1janwjDuRPYTdu5xdC+gOjwkrh9V+KLoC+z0sAhfZGGKkyrgPpRPts4cPpTZn9IfmwgIO/qDScuFSO6OZnGfUZGKjzPqGUTwwwcXz9x1iJBwlL8e1Ety4NaEf+vjC5gdOxAfM4N7L1mocU3rt8XqhhprOoUOFlMX7IEpCGBcVYm4zkuAKrtPQPqQvxFaV6OFJQfUgGCS4TVkYgrkJWe/JQ1BH0ZeI/AwBxY= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, 27 Sep 2023 14:39:21 -0700 Suren Baghdasaryan wrote: > > > > > >> The code should conceptually do: > > >> > > >> if (MPOL_MF_MOVE|MOVEALL) > > >> scan all vmas > > >> try to migrate the existing pages > > >> return success > > >> else if (MPOL_MF_MOVE* | MPOL_MF_STRICT) > > >> scan all vmas > > >> try to migrate the existing pages > > >> return -EIO if unmovable or migration failed > > >> else /* MPOL_MF_STRICT alone */ > > >> break early if meets unmovable and don't call mbind_range() at all > > >> else /* none of those flags */ > > >> check the ranges in test_walk, EFAULT without mbind_range() if discontig. > > With this change I think my temporary fix at > https://lore.kernel.org/all/20230918211608.3580629-1-surenb@google.com/ > can be removed because we either scan all vmas (which means we locked > them all) or we break early and do not call mbind_range() at all (in > which case we don't need vmas to be locked). Thanks, I dropped "mm: lock VMAs skipped by a failed queue_pages_range()"