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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,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 4ACB9C433C1 for ; Fri, 19 Mar 2021 16:12:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D5D826197D for ; Fri, 19 Mar 2021 16:11:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D5D826197D 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 49EAA6B006E; Fri, 19 Mar 2021 12:11:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 44F078D000B; Fri, 19 Mar 2021 12:11:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2CD468D0001; Fri, 19 Mar 2021 12:11:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0239.hostedemail.com [216.40.44.239]) by kanga.kvack.org (Postfix) with ESMTP id 0DB836B006E for ; Fri, 19 Mar 2021 12:11:59 -0400 (EDT) Received: from smtpin39.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id B7847181C856A for ; Fri, 19 Mar 2021 16:11:58 +0000 (UTC) X-FDA: 77937115116.39.28D36E8 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf21.hostedemail.com (Postfix) with ESMTP id 3CECDE0007F7 for ; Fri, 19 Mar 2021 16:11:41 +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 DF226AC75; Fri, 19 Mar 2021 16:11:39 +0000 (UTC) Subject: Re: [PATCH 1/7] mm/page_alloc: Move gfp_allowed_mask enforcement to prepare_alloc_pages To: Mel Gorman , Andrew Morton Cc: Chuck Lever , Jesper Dangaard Brouer , Christoph Hellwig , Alexander Duyck , Matthew Wilcox , LKML , Linux-Net , Linux-MM , Linux-NFS References: <20210312154331.32229-1-mgorman@techsingularity.net> <20210312154331.32229-2-mgorman@techsingularity.net> From: Vlastimil Babka Message-ID: <2b5b3bea-c247-0564-f2d4-1dad28f176ed@suse.cz> Date: Fri, 19 Mar 2021 17:11:39 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <20210312154331.32229-2-mgorman@techsingularity.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Stat-Signature: jezoe98swjkymi1xymoiat3qqy7q1fyi X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 3CECDE0007F7 Received-SPF: none (suse.cz>: No applicable sender policy available) receiver=imf21; identity=mailfrom; envelope-from=""; helo=mx2.suse.de; client-ip=195.135.220.15 X-HE-DKIM-Result: none/none X-HE-Tag: 1616170301-440813 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 3/12/21 4:43 PM, Mel Gorman wrote: > __alloc_pages updates GFP flags to enforce what flags are allowed > during a global context such as booting or suspend. This patch moves the > enforcement from __alloc_pages to prepare_alloc_pages so the code can be > shared between the single page allocator and a new bulk page allocator. > > When moving, it is obvious that __alloc_pages() and __alloc_pages > use different names for the same variable. This is an unnecessary > complication so rename gfp_mask to gfp in prepare_alloc_pages() so the > name is consistent. > > No functional change. Hm, I have some doubts. > Signed-off-by: Mel Gorman > --- > mm/page_alloc.c | 25 +++++++++++++------------ > 1 file changed, 13 insertions(+), 12 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 00b67c47ad87..f0c1d74ead6f 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -4914,15 +4914,18 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, > return page; > } > > -static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order, > +static inline bool prepare_alloc_pages(gfp_t gfp, unsigned int order, > int preferred_nid, nodemask_t *nodemask, > struct alloc_context *ac, gfp_t *alloc_gfp, > unsigned int *alloc_flags) > { > - ac->highest_zoneidx = gfp_zone(gfp_mask); > - ac->zonelist = node_zonelist(preferred_nid, gfp_mask); > + gfp &= gfp_allowed_mask; > + *alloc_gfp = gfp; > + ... > @@ -4980,8 +4983,6 @@ struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid, > return NULL; > } > > - gfp &= gfp_allowed_mask; > - alloc_gfp = gfp; > if (!prepare_alloc_pages(gfp, order, preferred_nid, nodemask, &ac, > &alloc_gfp, &alloc_flags)) > return NULL; As a result, "gfp" doesn't have the restrictions by gfp_allowed_mask applied, only alloc_gfp does. But in case we go to slowpath, before going there we throw away the current alloc_gfp: alloc_gfp = current_gfp_context(gfp); ... page = __alloc_pages_slowpath(alloc_gfp, ...); So we lost the gfp_allowed_mask restrictions here?