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| Started by | Mel Gorman <mgorman@techsingularity.net> |
|---|---|
| First post | 2015-08-24 14:20 +0200 |
| Last post | 2015-08-25 16:40 +0200 |
| Articles | 2 — 2 participants |
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[PATCH 06/12] mm, page_alloc: Use masks and shifts when converting GFP flags to migrate types Mel Gorman <mgorman@techsingularity.net> - 2015-08-24 14:20 +0200
Re: [PATCH 06/12] mm, page_alloc: Use masks and shifts when converting GFP flags to migrate types Vlastimil Babka <vbabka@suse.cz> - 2015-08-25 16:40 +0200
| From | Mel Gorman <mgorman@techsingularity.net> |
|---|---|
| Date | 2015-08-24 14:20 +0200 |
| Subject | [PATCH 06/12] mm, page_alloc: Use masks and shifts when converting GFP flags to migrate types |
| Message-ID | <q0YTg-7q8-25@gated-at.bofh.it> |
This patch redefines which GFP bits are used for specifying mobility and
the order of the migrate types. Once redefined it's possible to convert
GFP flags to a migrate type with a simple mask and shift. The only downside
is that readers of OOM kill messages and allocation failures may have been
used to the existing values but scripts/gfp-translate will help.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
include/linux/gfp.h | 12 +++++++-----
include/linux/mmzone.h | 2 +-
2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index ad35f300b9a4..a10347ca5053 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -14,7 +14,7 @@ struct vm_area_struct;
#define ___GFP_HIGHMEM 0x02u
#define ___GFP_DMA32 0x04u
#define ___GFP_MOVABLE 0x08u
-#define ___GFP_WAIT 0x10u
+#define ___GFP_RECLAIMABLE 0x10u
#define ___GFP_HIGH 0x20u
#define ___GFP_IO 0x40u
#define ___GFP_FS 0x80u
@@ -29,7 +29,7 @@ struct vm_area_struct;
#define ___GFP_NOMEMALLOC 0x10000u
#define ___GFP_HARDWALL 0x20000u
#define ___GFP_THISNODE 0x40000u
-#define ___GFP_RECLAIMABLE 0x80000u
+#define ___GFP_WAIT 0x80000u
#define ___GFP_NOACCOUNT 0x100000u
#define ___GFP_NOTRACK 0x200000u
#define ___GFP_NO_KSWAPD 0x400000u
@@ -123,6 +123,7 @@ struct vm_area_struct;
/* This mask makes up all the page movable related flags */
#define GFP_MOVABLE_MASK (__GFP_RECLAIMABLE|__GFP_MOVABLE)
+#define GFP_MOVABLE_SHIFT 3
/* Control page allocator reclaim behavior */
#define GFP_RECLAIM_MASK (__GFP_WAIT|__GFP_HIGH|__GFP_IO|__GFP_FS|\
@@ -149,14 +150,15 @@ struct vm_area_struct;
/* Convert GFP flags to their corresponding migrate type */
static inline int gfpflags_to_migratetype(const gfp_t gfp_flags)
{
- WARN_ON((gfp_flags & GFP_MOVABLE_MASK) == GFP_MOVABLE_MASK);
+ VM_WARN_ON((gfp_flags & GFP_MOVABLE_MASK) == GFP_MOVABLE_MASK);
+ BUILD_BUG_ON((1UL << GFP_MOVABLE_SHIFT) != ___GFP_MOVABLE);
+ BUILD_BUG_ON((___GFP_MOVABLE >> GFP_MOVABLE_SHIFT) != MIGRATE_MOVABLE);
if (unlikely(page_group_by_mobility_disabled))
return MIGRATE_UNMOVABLE;
/* Group based on mobility */
- return (((gfp_flags & __GFP_MOVABLE) != 0) << 1) |
- ((gfp_flags & __GFP_RECLAIMABLE) != 0);
+ return (gfp_flags & GFP_MOVABLE_MASK) >> GFP_MOVABLE_SHIFT;
}
#ifdef CONFIG_HIGHMEM
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 99cf4209cd45..fc0457d005f8 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -37,8 +37,8 @@
enum {
MIGRATE_UNMOVABLE,
- MIGRATE_RECLAIMABLE,
MIGRATE_MOVABLE,
+ MIGRATE_RECLAIMABLE,
MIGRATE_PCPTYPES, /* the number of types on the pcp lists */
MIGRATE_RESERVE = MIGRATE_PCPTYPES,
#ifdef CONFIG_CMA
--
2.4.6
--
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| From | Vlastimil Babka <vbabka@suse.cz> |
|---|---|
| Date | 2015-08-25 16:40 +0200 |
| Subject | Re: [PATCH 06/12] mm, page_alloc: Use masks and shifts when converting GFP flags to migrate types |
| Message-ID | <q1nyi-Od-9@gated-at.bofh.it> |
| In reply to | #1212107 |
On 08/24/2015 02:09 PM, Mel Gorman wrote: > This patch redefines which GFP bits are used for specifying mobility and > the order of the migrate types. Once redefined it's possible to convert > GFP flags to a migrate type with a simple mask and shift. The only downside > is that readers of OOM kill messages and allocation failures may have been > used to the existing values but scripts/gfp-translate will help. Yeah after patches 7 and 8, this is not much of a concern :) > Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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