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| author | Mel Gorman | 2012-12-06 20:01:14 +0100 |
|---|---|---|
| committer | Linus Torvalds | 2012-12-06 20:17:33 +0100 |
| commit | 60177d31d215bc2b4c5a7aa6f742800e04fa0a92 (patch) | |
| tree | c45e15fc9b97b3ebffb6f7876512d35fe1d7aa46 /Documentation | |
| parent | Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus (diff) | |
| download | kernel-qcow2-linux-60177d31d215bc2b4c5a7aa6f742800e04fa0a92.tar.gz kernel-qcow2-linux-60177d31d215bc2b4c5a7aa6f742800e04fa0a92.tar.xz kernel-qcow2-linux-60177d31d215bc2b4c5a7aa6f742800e04fa0a92.zip | |
mm: compaction: validate pfn range passed to isolate_freepages_block
Commit 0bf380bc70ec ("mm: compaction: check pfn_valid when entering a
new MAX_ORDER_NR_PAGES block during isolation for migration") added a
check for pfn_valid() when isolating pages for migration as the scanner
does not necessarily start pageblock-aligned.
Since commit c89511ab2f8f ("mm: compaction: Restart compaction from near
where it left off"), the free scanner has the same problem. This patch
makes sure that the pfn range passed to isolate_freepages_block() is
within the same block so that pfn_valid() checks are unnecessary.
In answer to Henrik's wondering why others have not reported this:
reproducing this requires a large enough hole with the right aligment to
have compaction walk into a PFN range with no memmap. Size and
alignment depends in the memory model - 4M for FLATMEM and 128M for
SPARSEMEM on x86. It needs a "lucky" machine.
Reported-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
0 files changed, 0 insertions, 0 deletions