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Thu, 21 Dec 2023 11:26:44 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id D3FCLPQghGXHWgAAD6G6ig (envelope-from ); Thu, 21 Dec 2023 11:26:44 +0000 Received: by quack3.suse.cz (Postfix, from userid 1000) id 69F04A07E3; Thu, 21 Dec 2023 12:26:44 +0100 (CET) Date: Thu, 21 Dec 2023 12:26:44 +0100 From: Jan Kara To: Christoph Hellwig Cc: linux-mm@kvack.org, "Matthew Wilcox (Oracle)" , Jan Kara , David Howells , Brian Foster , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 10/17] pagevec: Add ability to iterate a queue Message-ID: <20231221112644.2ijv6c5zooclcqtm@quack3> References: <20231218153553.807799-1-hch@lst.de> <20231218153553.807799-11-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231218153553.807799-11-hch@lst.de> X-Rspamd-Queue-Id: 6EC1640009 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: d1k9njh93o4pze6dow5e3tj1ugkdaqhw X-HE-Tag: 1703158006-515057 X-HE-Meta: U2FsdGVkX19qQubBxyYEhAGeLMwzyNmr6M8gr5sMKkno5lhT3Wc2tl6E1mKF8rFekg5xNUc+ILxj646UM3pAZfdRwahvxcGXBY4ZaurM/O7SVycil23Ehs1QPf3Q+nyepBBVfTb45MWjz3McO6amFF7ssG5r39fVGbKEdvVWOa/DuQU4p3SUol1QM1HKJT05e2eSrWdTc+x73vwlZVjlAhBAxwkSk1km2c4eC0sk37JBhpWnaVz7CII3I3G0WU6Z23M2NqozhB0XhhRgwHT3RpFcnw/68RYJN5jYBlD71jkAN9V2IJzC9PzoCRLF+GvEifoGSlbUn7WExej9/dqzePv45mbugVh0+/WCu63yC05QoIQ45C0IwIftEDWJG3gyzj78OpL+s5CO71NUUsH3Yk/hB7P2izUxc6h+dxCf+NlvrGQNtXzCbsOR4VjW8krtRvpp1uYbTKYTa6yIOvtaGW/gZv6RklmgkcyoWjIgbMMEbfH3sFaJx9jUGvy1khXIMlmvaJ388upggU9HUXkg8IipcAzjmNMbp5R331zjB96M3UZN5ZqhEALAYHY6TX3EphvPlaw5Rn5Aw8QtytlBq6CbBFcDp+ozd+OyiJcV7Kr8UzC8EE3cxQmKgQN1ni6TXF31oDV5YMHD/ORH1SMr6/EDXW9gRIKa83jf4PULV/tU0ElyawInnOcIzaCEXRp2E5P4A+UEYCLIh1TS7t6vNp6emaWsU2x4uLusm2s4W1hezBiWS9XbSwYk/6lmMs8dsC7l5yvH5bwECDG6IvMyKbNZhIfU3F7dKwDHnUhek4xQWQsnsN9gE7ipbKbTrjQWwoGxbWv7lJtrMXqbUIkswqLw6mzlTqfEeBBrmiQJ/J7aWxuozdrn/mcnoUPplZ0Hjr7hgRoDZfnjkZBaNhVcIzfNHkEIG/H0FKR9wxSzJnBQmaSzJTE9EAOHQPo9SgP3qggNykTWrX0oLg2JxjL FeNYhgAV NElSbiTMMLpgcgleRGlDew21be4vowVt4ogEkE3xAwcjOWYFfESk0H/DU4cEnRoJH47qRG9E6EeXFrtjB5fyQHBTalBUHpny3/CyEj6ZgRVKsYPrOgtO90lR3zBdtaxHU5CGy2e+ecHfvFRypKIMxtr+D7btjMR62W4XP4ToSMj+fkdpEKc7yxWTH2AyYe4N2Ypzd1jmdtsSlsM83gi+x0dCW/Q/2Da3qEWkSt6G3QemVfH5CqorNpkkgK5sGl1sL1KLnt1UzI8UJlryR/Wo30Cdwdy0dvaO5oYq3T6lGUh5QOeomKaa89VY/RJci7dfik4mYskzQhuWjIaBsf1b8QXqQTw== 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 18-12-23 16:35:46, Christoph Hellwig wrote: > From: "Matthew Wilcox (Oracle)" > > Add a loop counter inside the folio_batch to let us iterate from 0-nr > instead of decrementing nr and treating the batch as a stack. It would > generate some very weird and suboptimal I/O patterns for page writeback > to iterate over the batch as a stack. > > Signed-off-by: Matthew Wilcox (Oracle) > Signed-off-by: Christoph Hellwig Looks good. Feel free to add: Reviewed-by: Jan Kara Honza > --- > include/linux/pagevec.h | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h > index 87cc678adc850b..fcc06c300a72c3 100644 > --- a/include/linux/pagevec.h > +++ b/include/linux/pagevec.h > @@ -27,6 +27,7 @@ struct folio; > */ > struct folio_batch { > unsigned char nr; > + unsigned char i; > bool percpu_pvec_drained; > struct folio *folios[PAGEVEC_SIZE]; > }; > @@ -40,12 +41,14 @@ struct folio_batch { > static inline void folio_batch_init(struct folio_batch *fbatch) > { > fbatch->nr = 0; > + fbatch->i = 0; > fbatch->percpu_pvec_drained = false; > } > > static inline void folio_batch_reinit(struct folio_batch *fbatch) > { > fbatch->nr = 0; > + fbatch->i = 0; > } > > static inline unsigned int folio_batch_count(struct folio_batch *fbatch) > @@ -75,6 +78,21 @@ static inline unsigned folio_batch_add(struct folio_batch *fbatch, > return folio_batch_space(fbatch); > } > > +/** > + * folio_batch_next - Return the next folio to process. > + * @fbatch: The folio batch being processed. > + * > + * Use this function to implement a queue of folios. > + * > + * Return: The next folio in the queue, or NULL if the queue is empty. > + */ > +static inline struct folio *folio_batch_next(struct folio_batch *fbatch) > +{ > + if (fbatch->i == fbatch->nr) > + return NULL; > + return fbatch->folios[fbatch->i++]; > +} > + > void __folio_batch_release(struct folio_batch *pvec); > > static inline void folio_batch_release(struct folio_batch *fbatch) > -- > 2.39.2 > -- Jan Kara SUSE Labs, CR