From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-la0-f46.google.com (mail-la0-f46.google.com [209.85.215.46]) by kanga.kvack.org (Postfix) with ESMTP id 786736B0038 for ; Wed, 7 Jan 2015 04:37:02 -0500 (EST) Received: by mail-la0-f46.google.com with SMTP id q1so2340496lam.5 for ; Wed, 07 Jan 2015 01:37:01 -0800 (PST) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id da3si28761015wib.31.2015.01.07.01.37.01 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 07 Jan 2015 01:37:01 -0800 (PST) Message-ID: <54ACFE3A.4070502@suse.cz> Date: Wed, 07 Jan 2015 10:36:58 +0100 From: Vlastimil Babka MIME-Version: 1.0 Subject: Re: [PATCH V4 1/4] mm: set page->pfmemalloc in prep_new_page() References: <1420478263-25207-1-git-send-email-vbabka@suse.cz> <1420478263-25207-2-git-send-email-vbabka@suse.cz> <20150106143008.GA20860@dhcp22.suse.cz> <54AC4F5F.90306@suse.cz> <20150106214416.GA8391@dhcp22.suse.cz> In-Reply-To: <20150106214416.GA8391@dhcp22.suse.cz> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Mel Gorman , Zhang Yanfei , Minchan Kim , David Rientjes , Rik van Riel , "Aneesh Kumar K.V" , "Kirill A. Shutemov" , Johannes Weiner , Joonsoo Kim On 01/06/2015 10:44 PM, Michal Hocko wrote: > On Tue 06-01-15 22:10:55, Vlastimil Babka wrote: >> On 01/06/2015 03:30 PM, Michal Hocko wrote: > [...] >> > diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> > index 1bb65e6f48dd..1682d766cb8e 100644 >> > --- a/mm/page_alloc.c >> > +++ b/mm/page_alloc.c >> > @@ -2175,10 +2175,11 @@ zonelist_scan: >> > } >> > >> > try_this_zone: >> > - page = buffered_rmqueue(preferred_zone, zone, order, >> > + do { >> > + page = buffered_rmqueue(preferred_zone, zone, order, >> > gfp_mask, migratetype); >> > - if (page) >> > - break; >> > + } while (page && prep_new_page(page, order, gfp_mask, >> > + alloc_flags)); >> >> Hm but here we wouldn't return page on success. > > Right. > >> I wonder if you overlooked the return, hence your "not breaking out of >> the loop" remark? > > This was merely to show the intention. Sorry for not being clear enough. OK, but I don't see other way than to follow this do-while with another if (page) return page; So I think it would be more complicated than now. We wouldn't even be able to remove the 'try_this_zone' label, since it's used for goto from elsewhere as well. Now that I'm thinking of it, maybe we should have a "goto zonelist_scan" there instead. We discard a bad page and might come below the watermarks. But the chances of this mattering are tiny I guess. -- 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