From: Pavel Machek <pavel@ucw.cz>
To: Anisse Astier <anisse@astier.eu>
Cc: linux-mm@kvack.org, linux-pm@vger.kernel.org,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Laura Abbott <labbott@fedoraproject.org>,
Mel Gorman <mgorman@suse.de>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
Andi Kleen <andi@firstfloor.org>,
Andrew Morton <akpm@linux-foundation.org>,
Brad Spengler <spender@grsecurity.net>,
Dave Hansen <dave.hansen@intel.com>,
David Rientjes <rientjes@google.com>,
Jianyu Zhan <nasa4836@gmail.com>,
Kees Cook <keescook@chromium.org>,
Len Brown <len.brown@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Mathias Krause <minipli@googlemail.com>,
Michal Hocko <mhocko@suse.com>, PaX Team <pageexec@freemail.hu>,
Peter Zijlstra <peterz@infradead.org>,
Vlastimil Babka <vbabka@suse.cz>,
Yves-Alexis Perez <corsac@debian.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PM / Hibernate: allow hibernation with PAGE_POISONING_ZERO
Date: Mon, 12 Sep 2016 13:32:38 +0200 [thread overview]
Message-ID: <20160912113238.GA30927@amd> (raw)
In-Reply-To: <1473410612-6207-1-git-send-email-anisse@astier.eu>
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 <anisse@astier.eu>
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Laura Abbott <labbott@fedoraproject.org>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Looks reasonable to me.
Acked-by: Pavel Machek <pavel@ucw.cz>
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
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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WARNING: multiple messages have this Message-ID (diff)
From: Pavel Machek <pavel@ucw.cz>
To: Anisse Astier <anisse@astier.eu>
Cc: linux-mm@kvack.org, linux-pm@vger.kernel.org,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Laura Abbott <labbott@fedoraproject.org>,
Mel Gorman <mgorman@suse.de>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
Andi Kleen <andi@firstfloor.org>,
Andrew Morton <akpm@linux-foundation.org>,
Brad Spengler <spender@grsecurity.net>,
Dave Hansen <dave.hansen@intel.com>,
David Rientjes <rientjes@google.com>,
Jianyu Zhan <nasa4836@gmail.com>,
Kees Cook <keescook@chromium.org>,
Len Brown <len.brown@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Mathias Krause <minipli@googlemail.com>,
Michal Hocko <mhocko@suse.com>, PaX Team <pageexec@freemail.hu>,
Peter Zijlstra <peterz@infradead.org>,
Vlastimil Babka <vbabka@suse.cz>,
Yves-Alexis Perez <corsac@debian.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PM / Hibernate: allow hibernation with PAGE_POISONING_ZERO
Date: Mon, 12 Sep 2016 13:32:38 +0200 [thread overview]
Message-ID: <20160912113238.GA30927@amd> (raw)
In-Reply-To: <1473410612-6207-1-git-send-email-anisse@astier.eu>
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 <anisse@astier.eu>
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Laura Abbott <labbott@fedoraproject.org>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Looks reasonable to me.
Acked-by: Pavel Machek <pavel@ucw.cz>
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
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2016-09-12 11:32 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-09 8:43 [PATCH] PM / Hibernate: allow hibernation with PAGE_POISONING_ZERO Anisse Astier
2016-09-09 8:43 ` Anisse Astier
2016-09-09 18:29 ` Kees Cook
2016-09-09 18:29 ` Kees Cook
2016-09-09 18:29 ` Kees Cook
2016-09-12 11:32 ` Pavel Machek [this message]
2016-09-12 11:32 ` Pavel Machek
2016-09-12 15:19 ` Anisse Astier
2016-09-12 17:47 ` Pavel Machek
2016-09-12 17:47 ` Pavel Machek
2016-09-12 17:47 ` Pavel Machek
2016-09-14 1:00 ` Rafael J. Wysocki
2016-09-14 1:00 ` Rafael J. Wysocki
2016-09-14 1:00 ` Rafael J. Wysocki
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