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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F93FC433F5 for ; Thu, 18 Nov 2021 23:03:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 92BB361A81 for ; Thu, 18 Nov 2021 23:03:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 92BB361A81 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id A94C16B0072; Thu, 18 Nov 2021 18:03:15 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A44816B0073; Thu, 18 Nov 2021 18:03:15 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8E5416B0074; Thu, 18 Nov 2021 18:03:15 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0243.hostedemail.com [216.40.44.243]) by kanga.kvack.org (Postfix) with ESMTP id 7FB456B0072 for ; Thu, 18 Nov 2021 18:03:15 -0500 (EST) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 3742282D35D2 for ; Thu, 18 Nov 2021 23:03:05 +0000 (UTC) X-FDA: 78823578330.06.A07E6C0 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by imf21.hostedemail.com (Postfix) with ESMTP id A4D82D0369D5 for ; Thu, 18 Nov 2021 23:03:03 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 50AEE212CC; Thu, 18 Nov 2021 23:03:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1637276583; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=0VtH5sIKi/WbgeOAmRZTPkdFqlDqVx/oup6dlz2q7k4=; b=pfs+kyZkxQ60Ms5ibpPdnY/Bqak2ru5b9+dL+GA5SIV3OqPehJbo686Pcyx0enWo4EDMa2 q5uMbShdyAcaz6Dr9gU7tugww6Ev0wiDgFGIjsD2bkNibBGSWsKb1YNcd9kuKaWbbmxIfO 1HBiOQeFd5wwHvTBRPkSzhMRkgTQ/r0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1637276583; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=0VtH5sIKi/WbgeOAmRZTPkdFqlDqVx/oup6dlz2q7k4=; b=WNWIB8ZG+nPApb7FKizK8J+ry6HYhXw2oF+q8YpT6QtuiIOBfQxv7ypCyYUip6rOF2bgM+ J/HAg+AphsRRJgAA== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id ECDFA13B11; Thu, 18 Nov 2021 23:03:00 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id pvlWKqTblmGoPQAAMHmgww (envelope-from ); Thu, 18 Nov 2021 23:03:00 +0000 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit MIME-Version: 1.0 From: "NeilBrown" To: "Mel Gorman" Cc: "Michal Hocko" , "Andrew Morton" , "Thierry Reding" , "Matthew Wilcox" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Mel Gorman" Subject: Re: [PATCH] MM: discard __GFP_ATOMIC In-reply-to: <20211118132753.GB3366@techsingularity.net> References: <163712397076.13692.4727608274002939094@noble.neil.brown.name>, , <20211118132753.GB3366@techsingularity.net> Date: Fri, 19 Nov 2021 10:02:55 +1100 Message-id: <163727657594.13692.10357464624495712361@noble.neil.brown.name> X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: A4D82D0369D5 X-Stat-Signature: hth9x4wnkqpuzm7mmoi689s3k5pmq63d Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=pfs+kyZk; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=WNWIB8ZG; spf=pass (imf21.hostedemail.com: domain of neilb@suse.de designates 195.135.220.28 as permitted sender) smtp.mailfrom=neilb@suse.de; dmarc=pass (policy=none) header.from=suse.de X-HE-Tag: 1637276583-760515 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 Fri, 19 Nov 2021, Mel Gorman wrote: > On Thu, Nov 18, 2021 at 10:22:36AM +0100, Michal Hocko wrote: > > [Cc Mel] > > > > I think this patch should be ok. There are few direct users of __GFP_HIGH > and some of them are borderline silly (e.g. mm/shmem.c specifying > __GFP_HIGH|__GFP_NOMEMALLOC) while others just look questionable ( > drivers/md/raid10.c seems to assume __GFP_HIGH guarantees allocation > success). Xen appears to be the worst abuser of __GFP_HIGH. That __GFP_HIGH in raid10.c is passed to mempool_alloc(), so there is no assumption that __GFP_HIGH will provide guarantees - the mempool does that. The comment - which I wrote 4 years ago and don't recall at all - suggest it was purely about performance - get error handling out of the way quickly. I doubt I could justify it if challenged... Thanks, NeilBrown > > -- > Mel Gorman > SUSE Labs > >