From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id 526826B004F for ; Wed, 26 Oct 2011 03:10:33 -0400 (EDT) Received: from hpaq2.eem.corp.google.com (hpaq2.eem.corp.google.com [172.25.149.2]) by smtp-out.google.com with ESMTP id p9Q7AUYn013092 for ; Wed, 26 Oct 2011 00:10:30 -0700 Received: from pzk1 (pzk1.prod.google.com [10.243.19.129]) by hpaq2.eem.corp.google.com with ESMTP id p9Q7917Z003873 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NOT) for ; Wed, 26 Oct 2011 00:10:28 -0700 Received: by pzk1 with SMTP id 1so5247163pzk.9 for ; Wed, 26 Oct 2011 00:10:28 -0700 (PDT) Date: Wed, 26 Oct 2011 00:10:26 -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: TEXT/PLAIN; charset=US-ASCII 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 On Tue, 25 Oct 2011, Colin Cross wrote: > > 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. > > Only before interrupts are enabled, and then isn't it vulnerable to > the same livelock? Interrupts are off, single cpu, kswapd can't run. > If an allocation ever failed, which seems unlikely, why would retrying > help? > If you want to claim gfp_allowed_mask as a pm-only entity, then I see no problem with this approach. However, if gfp_allowed_mask would be allowed to temporarily change after init for another purpose then it would make sense to retry because another allocation with __GFP_FS on another cpu or kswapd could start making progress could allow for future memory freeing. The suggestion to add a hook directly into a pm-interface was so that we could isolate it only to suspend and, to me, is the most maintainable solution. -- 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