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Shutemov" , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Vlastimil Babka , Hugh Dickins , =?iso-8859-1?B?Suly9G1l?= Glisse , Andrea Arcangeli , "Aneesh Kumar K . V" , David Rientjes , Lance Roy , Ralph Campbell , Jason Gunthorpe , Dave Airlie , Thomas Hellstrom , Souptick Joarder , Mel Gorman , Jan Kara , Mike Kravetz , Huang Ying , Aaron Lu , Omar Sandoval , Thomas Gleixner , Vineeth Remanan Pillai , Daniel Jordan , Mike Rapoport , Joel Fernandes , Mark Rutland , Alexander Duyck , Pavel Tatashin , David Hildenbrand , Juergen Gross , Anthony Yznaga , Johannes Weiner , "Darrick J . Wong" , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v3 4/4] mm: remove unnecessary smp_wmb() in __SetPageUptodate() Message-ID: <20190925220357.GA162930@google.com> References: <20190914070518.112954-1-yuzhao@google.com> <20190924232459.214097-1-yuzhao@google.com> <20190924232459.214097-4-yuzhao@google.com> <20190924235036.GA24516@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190924235036.GA24516@bombadil.infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 24, 2019 at 04:50:36PM -0700, Matthew Wilcox wrote: > On Tue, Sep 24, 2019 at 05:24:59PM -0600, Yu Zhao wrote: > > +/* > > + * Only use this function when there is a following write barrier, e.g., > > + * an explicit smp_wmb() and/or the page will be added to page or swap > > + * cache locked. > > + */ > > static __always_inline void __SetPageUptodate(struct page *page) > > { > > VM_BUG_ON_PAGE(PageTail(page), page); > > - smp_wmb(); > > __set_bit(PG_uptodate, &page->flags); > > } > > Isn't this now the same as __SETPAGEFLAG(uptodate, Uptodate, PF_NO_TAIL)? Indeed. I'll use the macro in the next version.