linux-kernel - Re: [linux-pm] [PATCH] hibernation should work ok with memory hotplug

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 4 Nov 2008 08:08:35 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Nigel Cunningham <ncunningham@...a.org.au>
Cc:	Dave Hansen <dave@...ux.vnet.ibm.com>,
	Matt Tolentino <matthew.e.tolentino@...el.com>,
	linux-pm@...ts.osdl.org, Dave Hansen <haveblue@...ibm.com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org, pavel@...e.cz,
	Mel Gorman <mel@...net.ie>, Andy Whitcroft <apw@...dowen.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [linux-pm] [PATCH] hibernation should work ok with memory hotplug

On Tuesday, 4 of November 2008, Nigel Cunningham wrote:
> Hi.
> 
> On Mon, 2008-11-03 at 14:34 -0800, Dave Hansen wrote:
> > A node might have a node_start_pfn=0 and a node_end_pfn=100 (and it may
> > have only one zone).  But, there may be another node with
> > node_start_pfn=10 and a node_end_pfn=20.  This loop:
> > 
> >         for_each_zone(zone) {
> > 		...
> >                 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
> >                         if (page_is_saveable(zone, pfn))
> >                                 memory_bm_set_bit(orig_bm, pfn);
> >         }
> > 
> > will walk over the smaller node's pfn range multiple times.  Is this OK?
> > 
> > I think all you have to do to fix it is check page_zone(page) == zone
> > and skip out if they don't match.
> 
> So pfn 10 in the first node refers to the same memory as pfn 10 in the
> second node?

A pfn always refers to specific page frame and/or struct page, so yes.
However, in one of the nodes these pfns are sort of "invalid" (they point
to struct pages belonging to other zones).  AFAICS.

Thanks,
Rafael
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/