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Received: from willy by casper.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1redVS-0000000Hajc-01ec; Mon, 26 Feb 2024 16:07:06 +0000 Date: Mon, 26 Feb 2024 16:07:05 +0000 From: Matthew Wilcox To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton Subject: Re: [PATCH v2 1/2] mm/memfd: refactor memfd_tag_pins() and memfd_wait_for_pins() Message-ID: References: <20240226141324.278526-1-david@redhat.com> <20240226141324.278526-2-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240226141324.278526-2-david@redhat.com> X-Rspamd-Queue-Id: 7076540028 X-Rspam-User: X-Stat-Signature: iuzu5rue3ydhhoxkpxq6ytaqkxqc9xzx X-Rspamd-Server: rspam01 X-HE-Tag: 1708963630-559781 X-HE-Meta: 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 aM4THb2A 8MUeTZ34um2+O4zvb3C8+gmhNHvwLzqDvHss8iMX2Sul8WvEW+Q4umyN5hDUDqfj8xz/ICMFWgifDYCdBWeLOccvTlFO8zs2PWkgMZ/gP2frAr2EwBxgc1puwfzaosDLOFODGddU96GrvvNb267B6e3zy+HPdjJ1cELYxsf+2kToJnwJ5vIa3C+DdOw== 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: List-Subscribe: List-Unsubscribe: On Mon, Feb 26, 2024 at 03:13:23PM +0100, David Hildenbrand wrote: > + xas_for_each(xas, folio, ULONG_MAX) { > + if (!xa_is_value(folio) && memfd_folio_has_extra_refs(folio)) > xas_set_mark(xas, MEMFD_TAG_PINNED); ... we decline to tag value entries here ... > @@ -95,20 +90,15 @@ static int memfd_wait_for_pins(struct address_space *mapping) > > xas_set(&xas, 0); > xas_lock_irq(&xas); > - xas_for_each_marked(&xas, page, ULONG_MAX, MEMFD_TAG_PINNED) { > + xas_for_each_marked(&xas, folio, ULONG_MAX, MEMFD_TAG_PINNED) { > bool clear = true; > > - cache_count = 1; > - if (!xa_is_value(page) && > - PageTransHuge(page) && !PageHuge(page)) > - cache_count = HPAGE_PMD_NR; > - > - if (!xa_is_value(page) && cache_count != > - page_count(page) - total_mapcount(page)) { > + if (!xa_is_value(folio) && > + memfd_folio_has_extra_refs(folio)) { ... so we don't need to test it here because we'll never see any value entries. No?