From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id 24EDB6B003B for ; Wed, 26 Oct 2011 02:51:53 -0400 (EDT) Received: from hpaq6.eem.corp.google.com (hpaq6.eem.corp.google.com [172.25.149.6]) by smtp-out.google.com with ESMTP id p9Q6poit012087 for ; Tue, 25 Oct 2011 23:51:50 -0700 Received: from pzk36 (pzk36.prod.google.com [10.243.19.164]) by hpaq6.eem.corp.google.com with ESMTP id p9Q6os0c012547 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NOT) for ; Tue, 25 Oct 2011 23:51:48 -0700 Received: by pzk36 with SMTP id 36so6402342pzk.3 for ; Tue, 25 Oct 2011 23:51:48 -0700 (PDT) Date: Tue, 25 Oct 2011 23:51:45 -0700 (PDT) From: David Rientjes Subject: Re: [PATCH] mm: avoid livelock on !__GFP_FS allocations In-Reply-To: Message-ID: References: <1319524789-22818-1-git-send-email-ccross@android.com> <20111025090956.GA10797@suse.de> MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="397155492-1542067330-1319611906=:20273" Sender: owner-linux-mm@kvack.org List-ID: To: Colin Cross Cc: Mel Gorman , linux-kernel@vger.kernel.org, Andrew Morton , KAMEZAWA Hiroyuki , Andrea Arcangeli , linux-mm@kvack.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --397155492-1542067330-1319611906=:20273 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT On Tue, 25 Oct 2011, Colin Cross wrote: > >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c > >> index fef8dc3..59cd4ff 100644 > >> --- a/mm/page_alloc.c > >> +++ b/mm/page_alloc.c > >> @@ -1786,6 +1786,13 @@ should_alloc_retry(gfp_t gfp_mask, unsigned int order, > >> return 0; > >> > >> /* > >> + * If PM has disabled I/O, OOM is disabled and reclaim is unlikely > >> + * to make any progress. To prevent a livelock, don't retry. > >> + */ > >> + if (!(gfp_allowed_mask & __GFP_FS)) > >> + return 0; > >> + > >> + /* > >> * In this implementation, order <= PAGE_ALLOC_COSTLY_ORDER > >> * means __GFP_NOFAIL, but that may not be true in other > >> * implementations. > > > > Eek, this is precisely what we don't want and is functionally the same as > > what you initially proposed except it doesn't care about __GFP_NOFAIL. > > This is checking against gfp_allowed_mask, not gfp_mask. > gfp_allowed_mask is initialized to GFP_BOOT_MASK to start so that __GFP_FS is never allowed before the slab allocator is completely initialized, so you've now implicitly made all early boot allocations to be __GFP_NORETRY even though they may not pass it. --397155492-1542067330-1319611906=:20273-- -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org