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-rw-r--r--include/linux/gfp.h46
-rw-r--r--include/linux/skbuff.h6
2 files changed, 36 insertions, 16 deletions
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 440fca3e7e5d..b56e811b6f7c 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -29,12 +29,13 @@ struct vm_area_struct;
#define ___GFP_NOMEMALLOC 0x10000u
#define ___GFP_HARDWALL 0x20000u
#define ___GFP_THISNODE 0x40000u
-#define ___GFP_WAIT 0x80000u
+#define ___GFP_ATOMIC 0x80000u
#define ___GFP_NOACCOUNT 0x100000u
#define ___GFP_NOTRACK 0x200000u
-#define ___GFP_NO_KSWAPD 0x400000u
+#define ___GFP_DIRECT_RECLAIM 0x400000u
#define ___GFP_OTHER_NODE 0x800000u
#define ___GFP_WRITE 0x1000000u
+#define ___GFP_KSWAPD_RECLAIM 0x2000000u
/* If the above are modified, __GFP_BITS_SHIFT may need updating */
/*
@@ -71,7 +72,7 @@ struct vm_area_struct;
* __GFP_MOVABLE: Flag that this page will be movable by the page migration
* mechanism or reclaimed
*/
-#define __GFP_WAIT ((__force gfp_t)___GFP_WAIT) /* Can wait and reschedule? */
+#define __GFP_ATOMIC ((__force gfp_t)___GFP_ATOMIC) /* Caller cannot wait or reschedule */
#define __GFP_HIGH ((__force gfp_t)___GFP_HIGH) /* Should access emergency pools? */
#define __GFP_IO ((__force gfp_t)___GFP_IO) /* Can start physical IO? */
#define __GFP_FS ((__force gfp_t)___GFP_FS) /* Can call down to low-level FS? */
@@ -94,23 +95,37 @@ struct vm_area_struct;
#define __GFP_NOACCOUNT ((__force gfp_t)___GFP_NOACCOUNT) /* Don't account to kmemcg */
#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 */
/*
+ * A caller that is willing to wait may enter direct reclaim and will
+ * wake kswapd to reclaim pages in the background until the high
+ * watermark is met. A caller may wish to clear __GFP_DIRECT_RECLAIM to
+ * avoid unnecessary delays when a fallback option is available but
+ * still allow kswapd to reclaim in the background. The kswapd flag
+ * can be cleared when the reclaiming of pages would cause unnecessary
+ * disruption.
+ */
+#define __GFP_WAIT ((__force gfp_t)(___GFP_DIRECT_RECLAIM|___GFP_KSWAPD_RECLAIM))
+#define __GFP_DIRECT_RECLAIM ((__force gfp_t)___GFP_DIRECT_RECLAIM) /* Caller can reclaim */
+#define __GFP_KSWAPD_RECLAIM ((__force gfp_t)___GFP_KSWAPD_RECLAIM) /* kswapd can wake */
+
+/*
* This may seem redundant, but it's a way of annotating false positives vs.
* allocations that simply cannot be supported (e.g. page tables).
*/
#define __GFP_NOTRACK_FALSE_POSITIVE (__GFP_NOTRACK)
-#define __GFP_BITS_SHIFT 25 /* Room for N __GFP_FOO bits */
+#define __GFP_BITS_SHIFT 26 /* Room for N __GFP_FOO bits */
#define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
-/* This equals 0, but use constants in case they ever change */
-#define GFP_NOWAIT (GFP_ATOMIC & ~__GFP_HIGH)
-/* GFP_ATOMIC means both !wait (__GFP_WAIT not set) and use emergency pool */
-#define GFP_ATOMIC (__GFP_HIGH)
+/*
+ * GFP_ATOMIC callers can not sleep, need the allocation to succeed.
+ * A lower watermark is applied to allow access to "atomic reserves"
+ */
+#define GFP_ATOMIC (__GFP_HIGH|__GFP_ATOMIC|__GFP_KSWAPD_RECLAIM)
+#define GFP_NOWAIT (__GFP_KSWAPD_RECLAIM)
#define GFP_NOIO (__GFP_WAIT)
#define GFP_NOFS (__GFP_WAIT | __GFP_IO)
#define GFP_KERNEL (__GFP_WAIT | __GFP_IO | __GFP_FS)
@@ -119,10 +134,10 @@ struct vm_area_struct;
#define GFP_USER (__GFP_WAIT | __GFP_IO | __GFP_FS | __GFP_HARDWALL)
#define GFP_HIGHUSER (GFP_USER | __GFP_HIGHMEM)
#define GFP_HIGHUSER_MOVABLE (GFP_HIGHUSER | __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)
+#define GFP_IOFS (__GFP_IO | __GFP_FS | __GFP_KSWAPD_RECLAIM)
+#define GFP_TRANSHUGE ((GFP_HIGHUSER_MOVABLE | __GFP_COMP | \
+ __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN) & \
+ ~__GFP_KSWAPD_RECLAIM)
/* This mask makes up all the page movable related flags */
#define GFP_MOVABLE_MASK (__GFP_RECLAIMABLE|__GFP_MOVABLE)
@@ -164,6 +179,11 @@ static inline int gfpflags_to_migratetype(const gfp_t gfp_flags)
return (gfp_flags & GFP_MOVABLE_MASK) >> GFP_MOVABLE_SHIFT;
}
+static inline bool gfpflags_allow_blocking(const gfp_t gfp_flags)
+{
+ return gfp_flags & __GFP_DIRECT_RECLAIM;
+}
+
#ifdef CONFIG_HIGHMEM
#define OPT_ZONE_HIGHMEM ZONE_HIGHMEM
#else
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 24f4dfd94c51..4355129fff91 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1224,7 +1224,7 @@ static inline int skb_cloned(const struct sk_buff *skb)
static inline int skb_unclone(struct sk_buff *skb, gfp_t pri)
{
- might_sleep_if(pri & __GFP_WAIT);
+ might_sleep_if(gfpflags_allow_blocking(pri));
if (skb_cloned(skb))
return pskb_expand_head(skb, 0, 0, pri);
@@ -1308,7 +1308,7 @@ static inline int skb_shared(const struct sk_buff *skb)
*/
static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
{
- might_sleep_if(pri & __GFP_WAIT);
+ might_sleep_if(gfpflags_allow_blocking(pri));
if (skb_shared(skb)) {
struct sk_buff *nskb = skb_clone(skb, pri);
@@ -1344,7 +1344,7 @@ static inline struct sk_buff *skb_share_check(struct sk_buff *skb, gfp_t pri)
static inline struct sk_buff *skb_unshare(struct sk_buff *skb,
gfp_t pri)
{
- might_sleep_if(pri & __GFP_WAIT);
+ might_sleep_if(gfpflags_allow_blocking(pri));
if (skb_cloned(skb)) {
struct sk_buff *nskb = skb_copy(skb, pri);