linux-kernel - Re: [PATCH v2 3/3] PM / hibernate: Recycle safe pages after image restoration

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Message-ID: <20160811210615.GA28618@amd>
Date:	Thu, 11 Aug 2016 23:06:15 +0200
From:	Pavel Machek <pavel@....cz>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	Linux PM list <linux-pm@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 3/3] PM / hibernate: Recycle safe pages after image
 restoration

Hi!

> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> One of the memory bitmaps used by the hibernation image restoration
> code is freed after the image has been loaded.
> 
> That is not quite efficient, though, because the memory pages used
> for building that bitmap are known to be safe (ie. they were not
> used by the image kernel before hibernation) and the arch-specific
> code finalizing the image restoration may need them.  In that case
> it needs to allocate those pages again via the memory management
> subsystem, check if they are really safe again by consulting the
> other bitmaps and so on.
> 
> To avoid that, recycle those pages by putting them into the global
> list of known safe pages so that they can be given to the arch code
> right away when necessary.

Ok, so you are trying to gain speed here? How much is the speedup?

Best regards,
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html