mm: remove __GFP_NO_KSWAPD

When transparent huge pages were introduced, memory compaction and swap
storms were an issue, and the kernel had to be careful to not make THP
allocations cause pageout or compaction.

Now that we have working compaction deferral, kswapd is smart enough to
invoke compaction and the quadratic behaviour around isolate_free_pages
has been fixed, it should be safe to remove __GFP_NO_KSWAPD.

Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 4883f393f50a8049cc83298068b5751621a7a8dc..f9bc873ce7d6c353ab9b6fb4a7a9fce75854c8c8 100644 (file)
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -35,7 +35,6 @@ struct vm_area_struct;
 #else
 #define ___GFP_NOTRACK         0
 #endif
-#define ___GFP_NO_KSWAPD       0x400000u
 #define ___GFP_OTHER_NODE      0x800000u
 #define ___GFP_WRITE           0x1000000u
 
@@ -90,7 +89,6 @@ struct vm_area_struct;
 #define __GFP_RECLAIMABLE ((__force gfp_t)___GFP_RECLAIMABLE) /* Page is reclaimable */
 #define __GFP_NOTRACK  ((__force gfp_t)___GFP_NOTRACK)  /* Don't track with kmemcheck */
 
-#define __GFP_NO_KSWAPD        ((__force gfp_t)___GFP_NO_KSWAPD)
 #define __GFP_OTHER_NODE ((__force gfp_t)___GFP_OTHER_NODE) /* On behalf of other node */
 #define __GFP_WRITE    ((__force gfp_t)___GFP_WRITE)   /* Allocator intends to dirty page */
 
@@ -120,8 +118,7 @@ struct vm_area_struct;
                                 __GFP_MOVABLE)
 #define GFP_IOFS       (__GFP_IO | __GFP_FS)
 #define GFP_TRANSHUGE  (GFP_HIGHUSER_MOVABLE | __GFP_COMP | \
-                        __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN | \
-                        __GFP_NO_KSWAPD)
+                        __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN)
 
 #ifdef CONFIG_NUMA
 #define GFP_THISNODE   (__GFP_THISNODE | __GFP_NOWARN | __GFP_NORETRY)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c10a9b71e317908cfecef339ba5a7b2132aec9eb..cefac399039c7a0cad564526ebf07f1b3072822e 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2348,9 +2348,8 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
                goto nopage;
 
 restart:
-       if (!(gfp_mask & __GFP_NO_KSWAPD))
-               wake_all_kswapd(order, zonelist, high_zoneidx,
-                                               zone_idx(preferred_zone));
+       wake_all_kswapd(order, zonelist, high_zoneidx,
+                                       zone_idx(preferred_zone));
 
        /*
         * OK, we're below the kswapd watermark and have kicked background
@@ -2433,7 +2432,7 @@ rebalance:
         * has requested the system not be heavily disrupted, fail the
         * allocation now instead of entering direct reclaim
         */
-       if (deferred_compaction && (gfp_mask & __GFP_NO_KSWAPD))
+       if (deferred_compaction)
                goto nopage;
 
        /* Try direct reclaim and then allocating */