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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 1B366C433DF for ; Wed, 24 Jun 2020 01:03:01 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C067B214DB for ; Wed, 24 Jun 2020 01:03:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C067B214DB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=fromorbit.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 366946B0002; Tue, 23 Jun 2020 21:03:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 317866B0003; Tue, 23 Jun 2020 21:03:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 22EB96B0005; Tue, 23 Jun 2020 21:03:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0079.hostedemail.com [216.40.44.79]) by kanga.kvack.org (Postfix) with ESMTP id 09A226B0002 for ; Tue, 23 Jun 2020 21:03:00 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id A39802C7C for ; Wed, 24 Jun 2020 01:02:59 +0000 (UTC) X-FDA: 76962306078.21.vase20_00062d926e40 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin21.hostedemail.com (Postfix) with ESMTP id 84619180442D0 for ; Wed, 24 Jun 2020 01:02:59 +0000 (UTC) X-HE-Tag: vase20_00062d926e40 X-Filterd-Recvd-Size: 2767 Received: from mail110.syd.optusnet.com.au (mail110.syd.optusnet.com.au [211.29.132.97]) by imf30.hostedemail.com (Postfix) with ESMTP for ; Wed, 24 Jun 2020 01:02:58 +0000 (UTC) Received: from dread.disaster.area (pa49-180-124-177.pa.nsw.optusnet.com.au [49.180.124.177]) by mail110.syd.optusnet.com.au (Postfix) with ESMTPS id 2763010B2D4; Wed, 24 Jun 2020 11:02:54 +1000 (AEST) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1jntoT-0001jv-FK; Wed, 24 Jun 2020 11:02:53 +1000 Date: Wed, 24 Jun 2020 11:02:53 +1000 From: Dave Chinner To: Add@vger.kernel.org, support@vger.kernel.org, for@vger.kernel.org, async@vger.kernel.org, buffered@vger.kernel.org, reads@vger.kernel.org Cc: io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, Jens Axboe , Johannes Weiner Subject: Re: [PATCH 05/15] mm: allow read-ahead with IOCB_NOWAIT set Message-ID: <20200624010253.GB5369@dread.disaster.area> References: <20200618144355.17324-1-axboe@kernel.dk> <20200618144355.17324-6-axboe@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200618144355.17324-6-axboe@kernel.dk> User-Agent: Mutt/1.10.1 (2018-07-13) X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=X6os11be c=1 sm=1 tr=0 a=k3aV/LVJup6ZGWgigO6cSA==:117 a=k3aV/LVJup6ZGWgigO6cSA==:17 a=kj9zAlcOel0A:10 a=nTHF0DUjJn0A:10 a=ufHFDILaAAAA:8 a=7-415B0cAAAA:8 a=WCjB2_pVjg0caHknj34A:9 a=CjuIK1q_8ugA:10 a=ZmIg1sZ3JBWsdXgziEIF:22 a=biEYGPWJfzWAr4FL6Ov7:22 X-Rspamd-Queue-Id: 84619180442D0 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 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 Thu, Jun 18, 2020 at 08:43:45AM -0600, Jens Axboe wrote: > The read-ahead shouldn't block, so allow it to be done even if > IOCB_NOWAIT is set in the kiocb. > > Acked-by: Johannes Weiner > Signed-off-by: Jens Axboe > --- > mm/filemap.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/mm/filemap.c b/mm/filemap.c > index f0ae9a6308cb..3378d4fca883 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -2028,8 +2028,6 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb, > > page = find_get_page(mapping, index); > if (!page) { > - if (iocb->ki_flags & IOCB_NOWAIT) > - goto would_block; > page_cache_sync_readahead(mapping, > ra, filp, > index, last_index - index); Doesn't think break preadv2(RWF_NOWAIT) semantics for on buffered reads? i.e. this can now block on memory allocation for the page cache, which is something RWF_NOWAIT IO should not do.... Cheers, Dave. -- Dave Chinner david@fromorbit.com