From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCH] PM / Hibernate: allow hibernation with PAGE_POISONING_ZERO Date: Mon, 12 Sep 2016 19:47:47 +0200 Message-ID: <20160912174747.GA8285@amd> References: <1473410612-6207-1-git-send-email-anisse@astier.eu> <20160912113238.GA30927@amd> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org To: Anisse Astier Cc: David Rientjes , Michal Hocko , linux-pm@vger.kernel.org, Mathias Krause , Andrew Morton , "Rafael J . Wysocki" , Laura Abbott , linux-mm@kvack.org, Brad Spengler , Jianyu Zhan , Linus Torvalds , Vlastimil Babka , "Kirill A . Shutemov" , Yves-Alexis Perez , Kees Cook , linux-kernel@vger.kernel.org, Andi Kleen , Len Brown , Alan Cox , PaX Team , Dave Hansen , Mel Gorman , Peter Zijlstra List-Id: linux-pm@vger.kernel.org Hi! On Mon 2016-09-12 17:19:54, Anisse Astier wrote: > Le 12 sept. 2016 13:32, "Pavel Machek" a écrit : > > > > On Fri 2016-09-09 10:43:32, Anisse Astier wrote: > > > PAGE_POISONING_ZERO disables zeroing new pages on alloc, they are > > > poisoned (zeroed) as they become available. > > > In the hibernate use case, free pages will appear in the system without > > > being cleared, left there by the loading kernel. > > > > > > This patch will make sure free pages are cleared on resume when > > > PAGE_POISONING_ZERO is enabled. We free the pages just after resume > > > because we can't do it later: going through any device resume code might > > > allocate some memory and invalidate the free pages bitmap. > > > > > > Thus we don't need to disable hibernation when PAGE_POISONING_ZERO is > > > enabled. > > > > > > Signed-off-by: Anisse Astier > > > Cc: Kirill A. Shutemov > > > Cc: Laura Abbott > > > Cc: Mel Gorman > > > Cc: Rafael J. Wysocki > > > > Looks reasonable to me. > > > > Acked-by: Pavel Machek > > > > Actually.... this takes basically zero time come. Do we want to do it > > unconditionally? > > > > (Yes, it is free memory, but for sake of debugging, I guess zeros are > > preffered to random content that changed during hibernation.) > > > > (But that does not change the Ack.) > > > > Best regards, > > > Pavel > > -- > > I have no opposition on doing this unconditionally. I can send a v2 as soon > as I get closer to a computer. Actually, I'd keep this one as is, when it works and there are no problems for a release or so, we can delete the ifdefs. Thanks! Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- 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