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 D7AE7C433DB for ; Wed, 24 Feb 2021 17:24:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 84D6A64F0D for ; Wed, 24 Feb 2021 17:24:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235416AbhBXRYV (ORCPT ); Wed, 24 Feb 2021 12:24:21 -0500 Received: from mx2.suse.de ([195.135.220.15]:49956 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229644AbhBXRYR (ORCPT ); Wed, 24 Feb 2021 12:24:17 -0500 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 500ECAE56; Wed, 24 Feb 2021 17:23:35 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 2DC341E14EE; Wed, 24 Feb 2021 18:23:35 +0100 (CET) Date: Wed, 24 Feb 2021 18:23:35 +0100 From: Jan Kara To: Jens Axboe Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org Subject: Re: [PATCH 2/3] mm: use filemap_range_needs_writeback() for O_DIRECT reads Message-ID: <20210224172335.GE849@quack2.suse.cz> References: <20210224164455.1096727-1-axboe@kernel.dk> <20210224164455.1096727-3-axboe@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210224164455.1096727-3-axboe@kernel.dk> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed 24-02-21 09:44:54, Jens Axboe wrote: > For the generic page cache read helper, use the better variant of checking > for the need to call filemap_write_and_wait_range() when doing O_DIRECT > reads. 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 > --- > mm/filemap.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) Looks good to me. Feel free to add: Reviewed-by: Jan Kara Honza > > diff --git a/mm/filemap.c b/mm/filemap.c > index 13338f877677..77f1b527541e 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -2645,8 +2645,8 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) > > size = i_size_read(inode); > if (iocb->ki_flags & IOCB_NOWAIT) { > - if (filemap_range_has_page(mapping, iocb->ki_pos, > - iocb->ki_pos + count - 1)) > + if (filemap_range_needs_writeback(mapping, iocb->ki_pos, > + iocb->ki_pos + count - 1)) > return -EAGAIN; > } else { > retval = filemap_write_and_wait_range(mapping, > -- > 2.30.0 > -- Jan Kara SUSE Labs, CR