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d=linux-foundation.org; s=korg; t=1691176457; bh=KjLfStABFwUIAtuSAKNcnmOi2LteNNPlPp20ShgMzp4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Z0eePU9NC4Pz6n6vXCNvjXjwlqXDzzzr5i3qU2pMQKHmkgb5AhlUyg9FUUtR84vnj Zhk+jFYTAa/8XPVFoOiFEMxePF2hfUOKoJRQWf4aPeUTeLUzOv9oQhLUykgZa02sUW i8K5cksG4rlxLiAtQeTF7k4fI/GPmi0vCP1n8tWY= Date: Fri, 4 Aug 2023 12:14:16 -0700 From: Andrew Morton To: Suren Baghdasaryan Cc: torvalds@linux-foundation.org, jannh@google.com, willy@infradead.org, liam.howlett@oracle.com, david@redhat.com, peterx@redhat.com, ldufour@linux.ibm.com, vbabka@suse.cz, michel@lespinasse.org, jglisse@google.com, mhocko@suse.com, hannes@cmpxchg.org, dave@stgolabs.net, hughd@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org, kernel-team@android.com, Linus Torvalds Subject: Re: [PATCH v4 1/6] mm: enable page walking API to lock vmas during the walk Message-Id: <20230804121416.533bb81336ded8f170da097e@linux-foundation.org> In-Reply-To: <20230804152724.3090321-2-surenb@google.com> References: <20230804152724.3090321-1-surenb@google.com> <20230804152724.3090321-2-surenb@google.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-Rspam-User: X-Stat-Signature: xpyyw6aubk3njecxnuoasew98s6o18fc X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 9726480028 X-HE-Tag: 1691176459-62958 X-HE-Meta: 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 uUoyZBNQ nddo9dHO4ffQ1b9EIPNIaoZXoVn9o5FWIJG3oJhZ8OB3F+8GG6ea+ie4LyoSyMvOwFQMmJauvZcuIQee+g5OpIdqKpavEX1moNBrO3VBJ0mMTZtLLTbik+iSuezMmYXCTgdLimFzqIkB1qaiQPYtcjOqJNEnj0Grl4P3WzubS/Mb6RoePRCyPExy4Z2Pn/yNmdz7S+T/W25Xgf91jS4l61xwZ3uDsP9320+e3m2Ryo4hv7/5C9s9V/ODr3Ey2CF9etvnHWoowGRyL+l/njgcLIHD9h8hDjzB1feweC6AddZjclNl9I+1pCvEW6s+q84ZHpF0kp2jwegcW+czGscLZ4QBiK8BZWy1OOscb 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 Fri, 4 Aug 2023 08:27:19 -0700 Suren Baghdasaryan wrote: > walk_page_range() and friends often operate under write-locked mmap_lock. > With introduction of vma locks, the vmas have to be locked as well > during such walks to prevent concurrent page faults in these areas. > Add an additional member to mm_walk_ops to indicate locking requirements > for the walk. > > ... > > 18 files changed, 100 insertions(+), 20 deletions(-) > That's a big patch for a -stable backport. Presumably the various -stable maintainers will be wondering why we're doing this. But, as is so often the case, the changelog fails to describe any user-visible effects of the change. Please send this info and I'll add it to the changelog.