From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC035C433E0 for ; Wed, 24 Feb 2021 17:25:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 32AB664F0B for ; Wed, 24 Feb 2021 17:25:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 32AB664F0B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 91D746B006C; Wed, 24 Feb 2021 12:25:26 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8CAE56B0071; Wed, 24 Feb 2021 12:25:26 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7E21B6B0072; Wed, 24 Feb 2021 12:25:26 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0033.hostedemail.com [216.40.44.33]) by kanga.kvack.org (Postfix) with ESMTP id 6B37E6B006C for ; Wed, 24 Feb 2021 12:25:26 -0500 (EST) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 27487801BDB2 for ; Wed, 24 Feb 2021 17:25:26 +0000 (UTC) X-FDA: 77853837852.18.1169F52 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf19.hostedemail.com (Postfix) with ESMTP id C8A5B90009EB for ; Wed, 24 Feb 2021 17:25:21 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 84718ADDB; Wed, 24 Feb 2021 17:25:24 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 5EA371E14EE; Wed, 24 Feb 2021 18:25:24 +0100 (CET) Date: Wed, 24 Feb 2021 18:25:24 +0100 From: Jan Kara To: Jens Axboe Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org Subject: Re: [PATCH 3/3] iomap: use filemap_range_needs_writeback() for O_DIRECT reads Message-ID: <20210224172524.GF849@quack2.suse.cz> References: <20210224164455.1096727-1-axboe@kernel.dk> <20210224164455.1096727-4-axboe@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210224164455.1096727-4-axboe@kernel.dk> User-Agent: Mutt/1.10.1 (2018-07-13) X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: C8A5B90009EB X-Stat-Signature: 73nwen9htnx4wa9psdftjqz8op914jmg Received-SPF: none (suse.cz>: No applicable sender policy available) receiver=imf19; identity=mailfrom; envelope-from=""; helo=mx2.suse.de; client-ip=195.135.220.15 X-HE-DKIM-Result: none/none X-HE-Tag: 1614187521-718076 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 24-02-21 09:44:55, Jens Axboe wrote: > For reads, use the better variant of checking for the need to call > filemap_write_and_wait_range() when doing O_DIRECT. This avoids falling > back to the slow path for IOCB_NOWAIT, if there are no pages to wait for > (or write out). > > Signed-off-by: Jens Axboe Looks good to me. Feel free to add: Reviewed-by: Jan Kara Honza > --- > fs/iomap/direct-io.c | 24 ++++++++++++++++-------- > 1 file changed, 16 insertions(+), 8 deletions(-) > > diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c > index e2c4991833b8..8c35a0041f0f 100644 > --- a/fs/iomap/direct-io.c > +++ b/fs/iomap/direct-io.c > @@ -487,12 +487,28 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, > if (pos >= dio->i_size) > goto out_free_dio; > > + if (iocb->ki_flags & IOCB_NOWAIT) { > + if (filemap_range_needs_writeback(mapping, pos, end)) { > + ret = -EAGAIN; > + goto out_free_dio; > + } > + iomap_flags |= IOMAP_NOWAIT; > + } > + > if (iter_is_iovec(iter)) > dio->flags |= IOMAP_DIO_DIRTY; > } else { > iomap_flags |= IOMAP_WRITE; > dio->flags |= IOMAP_DIO_WRITE; > > + if (iocb->ki_flags & IOCB_NOWAIT) { > + if (filemap_range_has_page(mapping, pos, end)) { > + ret = -EAGAIN; > + goto out_free_dio; > + } > + iomap_flags |= IOMAP_NOWAIT; > + } > + > /* for data sync or sync, we need sync completion processing */ > if (iocb->ki_flags & IOCB_DSYNC) > dio->flags |= IOMAP_DIO_NEED_SYNC; > @@ -507,14 +523,6 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, > dio->flags |= IOMAP_DIO_WRITE_FUA; > } > > - if (iocb->ki_flags & IOCB_NOWAIT) { > - if (filemap_range_has_page(mapping, pos, end)) { > - ret = -EAGAIN; > - goto out_free_dio; > - } > - iomap_flags |= IOMAP_NOWAIT; > - } > - > if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) { > ret = -EAGAIN; > if (pos >= dio->i_size || pos + count > dio->i_size) > -- > 2.30.0 > -- Jan Kara SUSE Labs, CR