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mm: compaction: fix echo 1 > compact_memory return error issue

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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.

Signed-off-by: Jason Liu <r64343@freescale.com>
Suggested-by: David Rientjes <rientjes@google.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jason Liu 2013-01-11 14:31:47 -08:00 committed by Linus Torvalds
parent c0232ae861
commit 7964c06d66
1 changed files with 2 additions and 4 deletions
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6
mm/compaction.c
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@ -1210,7 +1210,7 @@ static int compact_node(int nid)
}
/* Compact all nodes in the system */
static int compact_nodes(void)
static void compact_nodes(void)
{
int nid;
@ -1219,8 +1219,6 @@ static int compact_nodes(void)
for_each_online_node(nid)
compact_node(nid);
return COMPACT_COMPLETE;
}
/* The written value is actually unused, all memory is compacted */
@ -1231,7 +1229,7 @@ int sysctl_compaction_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos)
{
if (write)
return compact_nodes();
compact_nodes();
return 0;
}