Re: [PATCH] mm: compaction: fix echo 1 > compact_memory return errorissue

From: Mel Gorman
Date: Mon Jan 07 2013 - 08:57:14 EST


On Sun, Jan 06, 2013 at 03:44:33PM +0800, Jason Liu wrote:
> when run the folloing command under shell, it will return error
> sh/$ echo 1 > /proc/sys/vm/compact_memory
> sh/$ sh: write error: Bad address
>
> After strace, I found the following log:
> ...
> write(1, "1\n", 2) = 3
> write(1, "", 4294967295) = -1 EFAULT (Bad address)
> write(2, "echo: write error: Bad address\n", 31echo: write error: Bad address
> ) = 31
>
> This tells system return 3(COMPACT_COMPLETE) after write data to compact_memory.
>
> The fix is to make the system just return 0 instead 3(COMPACT_COMPLETE) from
> sysctl_compaction_handler after compaction_nodes finished.
>
> Suggested-by:David Rientjes <rientjes@xxxxxxxxxx>
> Cc:Mel Gorman <mgorman@xxxxxxx>
> Cc:Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc:Rik van Riel <riel@xxxxxxxxxx>
> Cc:Minchan Kim <minchan@xxxxxxxxxx>
> Cc:KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> Signed-off-by: Jason Liu <r64343@xxxxxxxxxxxxx>

Acked-by: Mel Gorman <mgorman@xxxxxxx>

--
Mel Gorman
SUSE Labs
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