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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1qNzWL-004eOz-A1; Mon, 24 Jul 2023 17:38:57 +0000 Date: Mon, 24 Jul 2023 18:38:57 +0100 From: Matthew Wilcox To: Suren Baghdasaryan Cc: linux-mm@kvack.org, Arjun Roy , Eric Dumazet , linux-fsdevel@vger.kernel.org, Punit Agrawal Subject: Re: [PATCH v2 7/9] mm: Run the fault-around code under the VMA lock Message-ID: References: <20230711202047.3818697-1-willy@infradead.org> <20230711202047.3818697-8-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspamd-Queue-Id: 61D8E10001B X-Rspam-User: X-Stat-Signature: rjx56gjenq8fqjtxs1zar3p33taqamt7 X-Rspamd-Server: rspam01 X-HE-Tag: 1690220341-82239 X-HE-Meta: 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 56g7sRY7 Ya/HU7tQcWYOxv5XKytsJHzfyJqGgLEUyj/KhZNNjboOAeqGdX9ZiHILR7fg3k35grN4iu9Sa/qgnPIxJKFHLiPwGsEIImlBJMl0K4V6LtSohvl2fXH1kalIylOZ18YPt/Kn76itGY4chqm6mDyZRxquWzxzTsHwRC4b9xsgkUgTYBq3sR9N1dXvHbTdeVe3B886L 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 Thu, Jul 13, 2023 at 08:32:27PM -0700, Suren Baghdasaryan wrote: > On Tue, Jul 11, 2023 at 1:20 PM Matthew Wilcox (Oracle) > wrote: > > > > The map_pages fs method should be safe to run under the VMA lock instead > > of the mmap lock. This should have a measurable reduction in contention > > on the mmap lock. > > > > Signed-off-by: Matthew Wilcox (Oracle) > > I'll trust your claim that vmf->vma->vm_ops->map_pages() never rely on > mmap_lock. I think it makes sense but I did not check every case :) Fortunately, there's really only one implementation of ->map_pages() and it's filemap_map_pages(). afs_vm_map_pages() is a thin wrapper around it.