Re: [PATCH] mm: fix a regression with HIGHMEM introduced by changeset7f1290f2f2a4d

[David Rientjes]

On Thu, 15 Nov 2012, Andrew Morton wrote:

> From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Subject: revert "mm: fix-up zone present pages"
> 
> Revert
> 
> commit 7f1290f2f2a4d2c3f1b7ce8e87256e052ca23125
> Author:     Jianguo Wu <wujianguo@xxxxxxxxxx>
> AuthorDate: Mon Oct 8 16:33:06 2012 -0700
> Commit:     Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> CommitDate: Tue Oct 9 16:22:54 2012 +0900
> 
>     mm: fix-up zone present pages
> 
> 
> That patch tried to fix a issue when calculating zone->present_pages, but
> it caused a regression on 32bit systems with HIGHMEM.  With that
> changeset, reset_zone_present_pages() resets all zone->present_pages to
> zero, and fixup_zone_present_pages() is called to recalculate
> zone->present_pages when the boot allocator frees core memory pages into
> buddy allocator.  Because highmem pages are not freed by bootmem
> allocator, all highmem zones' present_pages becomes zero.
> 
> Various options for improving the situation are being discussed but for
> now, let's return to the 3.6 code.
> 
> Cc: Jianguo Wu <wujianguo@xxxxxxxxxx>
> Cc: Jiang Liu <jiang.liu@xxxxxxxxxx>
> Cc: Petr Tesarik <ptesarik@xxxxxxx>
> Cc: "Luck, Tony" <tony.luck@xxxxxxxxx>
> Cc: Mel Gorman <mel@xxxxxxxxx>
> Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
> Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
> Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
> Cc: David Rientjes <rientjes@xxxxxxxxxx>
> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>

Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/