From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-we0-f169.google.com (mail-we0-f169.google.com [74.125.82.169]) by kanga.kvack.org (Postfix) with ESMTP id BD5736B0038 for ; Wed, 18 Mar 2015 11:40:37 -0400 (EDT) Received: by webcq43 with SMTP id cq43so35492880web.2 for ; Wed, 18 Mar 2015 08:40:37 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id lt12si4323858wic.25.2015.03.18.08.40.35 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 18 Mar 2015 08:40:36 -0700 (PDT) Message-ID: <55099C72.1080102@suse.cz> Date: Wed, 18 Mar 2015 16:40:34 +0100 From: Vlastimil Babka MIME-Version: 1.0 Subject: Re: [PATCH] mm, memcg: sync allocation and memcg charge gfp flags for THP References: <1426514892-7063-1-git-send-email-mhocko@suse.cz> <55098D0A.8090605@suse.cz> <20150318150257.GL17241@dhcp22.suse.cz> In-Reply-To: <20150318150257.GL17241@dhcp22.suse.cz> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andrew Morton , Johannes Weiner , linux-mm@kvack.org, LKML On 03/18/2015 04:02 PM, Michal Hocko wrote: > On Wed 18-03-15 15:34:50, Vlastimil Babka wrote: >> On 03/16/2015 03:08 PM, Michal Hocko wrote: >>> @@ -1080,6 +1080,7 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, >>> unsigned long haddr; >>> unsigned long mmun_start; /* For mmu_notifiers */ >>> unsigned long mmun_end; /* For mmu_notifiers */ >>> + gfp_t huge_gfp = GFP_TRANSHUGE; /* for allocation and charge */ >> >> This value is actually never used. Is it here because the compiler emits a >> spurious non-initialized value warning otherwise? It should be easy for it >> to prove that setting new_page to something non-null implies initializing >> huge_gfp (in the hunk below), and NULL new_page means it doesn't reach the >> mem_cgroup_try_charge() call? > > No, I haven't tried to workaround the compiler. It just made the code > more obvious to me. I can remove the initialization if you prefer, of > course. Yeah IMHO it would be better to remove it, if possible. Leaving it has the (albeit small) chance that future patch will again use the value in the code before it's determined based on defrag setting. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org