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Mon, 06 Apr 2020 08:40:05 -0700 (PDT) MIME-Version: 1.0 References: <20200327225102.25061-1-walken@google.com> <20200327225102.25061-8-walken@google.com> <20200401134633.GS20696@hirez.programming.kicks-ass.net> In-Reply-To: <20200401134633.GS20696@hirez.programming.kicks-ass.net> From: Michel Lespinasse Date: Mon, 6 Apr 2020 08:39:53 -0700 Message-ID: Subject: Re: [PATCH v3 07/10] mmap locking API: add mmap_read_release() and mmap_read_unlock_non_owner() To: Peter Zijlstra Cc: Andrew Morton , linux-mm , LKML , Laurent Dufour , Vlastimil Babka , Matthew Wilcox , Liam Howlett , Jerome Glisse , Davidlohr Bueso , David Rientjes , Hugh Dickins , Ying Han , Jason Gunthorpe , Markus Elfring Content-Type: text/plain; charset="UTF-8" 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, Apr 1, 2020 at 6:46 AM Peter Zijlstra wrote: > On Fri, Mar 27, 2020 at 03:50:59PM -0700, Michel Lespinasse wrote: > > Add a couple APIs to allow splitting mmap_read_unlock() into two calls: > > - mmap_read_release(), called by the task that had taken the mmap lock; > > - mmap_read_unlock_non_owner(), called from a work queue. > > > > These apis are used by kernel/bpf/stackmap.c only. > > That code is an absolute abomination and should never have gotten > merged. I have to say, it's causing me some grief too :/ > That said; I would prefer a mmap_read_trylock_nonowner() over > mmap_read_release() existing. It only addresses part of the issue, but I suppose I could do that. Is this something I could append to the end of this series, or do I need to prepare a v4 for such changes ?