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Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20210408145057.GN2531743@casper.infradead.org> References: <20210408145057.GN2531743@casper.infradead.org> <161789062190.6155.12711584466338493050.stgit@warthog.procyon.org.uk> <161789066013.6155.9816857201817288382.stgit@warthog.procyon.org.uk> To: Matthew Wilcox Cc: dhowells@redhat.com, linux-fsdevel@vger.kernel.org, Linus Torvalds , Alexander Viro , Christoph Hellwig , linux-mm@kvack.org, linux-cachefs@redhat.com, linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, Trond Myklebust , Anna Schumaker , Steve French , Dominique Martinet , Jeff Layton , David Wysochanski , linux-kernel@vger.kernel.org Subject: Re: [PATCH v6 02/30] mm: Add set/end/wait functions for PG_private_2 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <14839.1617895534.1@warthog.procyon.org.uk> Date: Thu, 08 Apr 2021 16:25:34 +0100 Message-ID: <14840.1617895534@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 8B1B36000128 X-Stat-Signature: q7ekoyhfzdppqpgqdntm3s6j9jrfr3kn Received-SPF: none (redhat.com>: No applicable sender policy available) receiver=imf25; identity=mailfrom; envelope-from=""; helo=us-smtp-delivery-124.mimecast.com; client-ip=216.205.24.124 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1617895547-734184 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: Matthew Wilcox wrote: > > +void end_page_private_2(struct page *page) > > +{ > > + page = compound_head(page); > > + VM_BUG_ON_PAGE(!PagePrivate2(page), page); > > + clear_bit_unlock(PG_private_2, &page->flags); > > + wake_up_page_bit(page, PG_private_2); > > ... but when we try to end on a tail, we actually wake up the head ... Question is, should I remove compound_head() here or add it into the other functions? David