mm: page allocator: do not call direct reclaim for THP allocations while compaction is deferred

If compaction is deferred, direct reclaim is used to try to free enough
pages for the allocation to succeed.  For small high-orders, this has a
reasonable chance of success.  However, if the caller has specified
__GFP_NO_KSWAPD to limit the disruption to the system, it makes more sense
to fail the allocation rather than stall the caller in direct reclaim.
This patch skips direct reclaim if compaction is deferred and the caller
specifies __GFP_NO_KSWAPD.

Async compaction only considers a subset of pages so it is possible for
compaction to be deferred prematurely and not enter direct reclaim even in
cases where it should.  To compensate for this, this patch also defers
compaction only if sync compaction failed.

Signed-off-by: Mel Gorman <[email protected]>
Acked-by: Minchan Kim <[email protected]>
Reviewed-by: Rik van Riel<[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Dave Jones <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Andy Isaacson <[email protected]>
Cc: Nai Xia <[email protected]>
Cc: Johannes Weiner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions