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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1q7ipp-00H1l0-8n; Fri, 09 Jun 2023 20:35:49 +0000 Date: Fri, 9 Jun 2023 21:35:49 +0100 From: Matthew Wilcox To: Peter Xu Cc: Suren Baghdasaryan , akpm@linux-foundation.org, hannes@cmpxchg.org, mhocko@suse.com, josef@toxicpanda.com, jack@suse.cz, ldufour@linux.ibm.com, laurent.dufour@fr.ibm.com, michel@lespinasse.org, liam.howlett@oracle.com, jglisse@google.com, vbabka@suse.cz, minchan@google.com, dave@stgolabs.net, punit.agrawal@bytedance.com, lstoakes@gmail.com, hdanton@sina.com, apopple@nvidia.com, ying.huang@intel.com, david@redhat.com, yuzhao@google.com, dhowells@redhat.com, hughd@google.com, viro@zeniv.linux.org.uk, brauner@kernel.org, pasha.tatashin@soleen.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH v2 2/6] mm: handle swap page faults under VMA lock if page is uncontended Message-ID: References: <20230609005158.2421285-1-surenb@google.com> <20230609005158.2421285-3-surenb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: 5631k5sysmpjuszhc9wj3ofxxgm4kz54 X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 1649F1A0004 X-Rspam-User: X-HE-Tag: 1686342994-700648 X-HE-Meta: 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 mo1plgIO +8lBJGNRoiKVr3jID8NNpjXYA1c12sF3ek9sq7VEBLCgynGA49UkWZ56Ul5bRn+TU8m4dTiD/5r6WtXPb+gQDZCmeiBEqmxTdhSzzIICyJCFnIvbwLkeBTQLIkQ+jjkJSTb4N0qU2fE/b1BUXMsisIRYXthJ5AIEv1Mio 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, Jun 09, 2023 at 04:25:42PM -0400, Peter Xu wrote: > > bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm, > > unsigned int flags) > > { > > + /* Can't do this if not holding mmap_lock */ > > + if (flags & FAULT_FLAG_VMA_LOCK) > > + return false; > > If here what we need is the page lock, can we just conditionally release > either mmap lock or vma lock depending on FAULT_FLAG_VMA_LOCK? See patch 5 ...