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-rw-r--r--include/linux/gfp.h111
1 files changed, 96 insertions, 15 deletions
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 06b7e8cc80ac..412178afd423 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -21,7 +21,8 @@ struct vm_area_struct;
#define __GFP_DMA ((__force gfp_t)0x01u)
#define __GFP_HIGHMEM ((__force gfp_t)0x02u)
#define __GFP_DMA32 ((__force gfp_t)0x04u)
-
+#define __GFP_MOVABLE ((__force gfp_t)0x08u) /* Page is movable */
+#define GFP_ZONEMASK (__GFP_DMA|__GFP_HIGHMEM|__GFP_DMA32|__GFP_MOVABLE)
/*
* Action modifiers - doesn't change the zoning
*
@@ -51,7 +52,6 @@ struct vm_area_struct;
#define __GFP_HARDWALL ((__force gfp_t)0x20000u) /* Enforce hardwall cpuset memory allocs */
#define __GFP_THISNODE ((__force gfp_t)0x40000u)/* No fallback, no policies */
#define __GFP_RECLAIMABLE ((__force gfp_t)0x80000u) /* Page is reclaimable */
-#define __GFP_MOVABLE ((__force gfp_t)0x100000u) /* Page is movable */
#define __GFP_BITS_SHIFT 21 /* Room for 21 __GFP_FOO bits */
#define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
@@ -116,24 +116,105 @@ static inline int allocflags_to_migratetype(gfp_t gfp_flags)
((gfp_flags & __GFP_RECLAIMABLE) != 0);
}
-static inline enum zone_type gfp_zone(gfp_t flags)
-{
+#ifdef CONFIG_HIGHMEM
+#define OPT_ZONE_HIGHMEM ZONE_HIGHMEM
+#else
+#define OPT_ZONE_HIGHMEM ZONE_NORMAL
+#endif
+
#ifdef CONFIG_ZONE_DMA
- if (flags & __GFP_DMA)
- return ZONE_DMA;
+#define OPT_ZONE_DMA ZONE_DMA
+#else
+#define OPT_ZONE_DMA ZONE_NORMAL
#endif
+
#ifdef CONFIG_ZONE_DMA32
- if (flags & __GFP_DMA32)
- return ZONE_DMA32;
+#define OPT_ZONE_DMA32 ZONE_DMA32
+#else
+#define OPT_ZONE_DMA32 ZONE_NORMAL
#endif
- if ((flags & (__GFP_HIGHMEM | __GFP_MOVABLE)) ==
- (__GFP_HIGHMEM | __GFP_MOVABLE))
- return ZONE_MOVABLE;
-#ifdef CONFIG_HIGHMEM
- if (flags & __GFP_HIGHMEM)
- return ZONE_HIGHMEM;
+
+/*
+ * GFP_ZONE_TABLE is a word size bitstring that is used for looking up the
+ * zone to use given the lowest 4 bits of gfp_t. Entries are ZONE_SHIFT long
+ * and there are 16 of them to cover all possible combinations of
+ * __GFP_DMA, __GFP_DMA32, __GFP_MOVABLE and __GFP_HIGHMEM
+ *
+ * The zone fallback order is MOVABLE=>HIGHMEM=>NORMAL=>DMA32=>DMA.
+ * But GFP_MOVABLE is not only a zone specifier but also an allocation
+ * policy. Therefore __GFP_MOVABLE plus another zone selector is valid.
+ * Only 1bit of the lowest 3 bit (DMA,DMA32,HIGHMEM) can be set to "1".
+ *
+ * bit result
+ * =================
+ * 0x0 => NORMAL
+ * 0x1 => DMA or NORMAL
+ * 0x2 => HIGHMEM or NORMAL
+ * 0x3 => BAD (DMA+HIGHMEM)
+ * 0x4 => DMA32 or DMA or NORMAL
+ * 0x5 => BAD (DMA+DMA32)
+ * 0x6 => BAD (HIGHMEM+DMA32)
+ * 0x7 => BAD (HIGHMEM+DMA32+DMA)
+ * 0x8 => NORMAL (MOVABLE+0)
+ * 0x9 => DMA or NORMAL (MOVABLE+DMA)
+ * 0xa => MOVABLE (Movable is valid only if HIGHMEM is set too)
+ * 0xb => BAD (MOVABLE+HIGHMEM+DMA)
+ * 0xc => DMA32 (MOVABLE+HIGHMEM+DMA32)
+ * 0xd => BAD (MOVABLE+DMA32+DMA)
+ * 0xe => BAD (MOVABLE+DMA32+HIGHMEM)
+ * 0xf => BAD (MOVABLE+DMA32+HIGHMEM+DMA)
+ *
+ * ZONES_SHIFT must be <= 2 on 32 bit platforms.
+ */
+
+#if 16 * ZONES_SHIFT > BITS_PER_LONG
+#error ZONES_SHIFT too large to create GFP_ZONE_TABLE integer
+#endif
+
+#define GFP_ZONE_TABLE ( \
+ (ZONE_NORMAL << 0 * ZONES_SHIFT) \
+ | (OPT_ZONE_DMA << __GFP_DMA * ZONES_SHIFT) \
+ | (OPT_ZONE_HIGHMEM << __GFP_HIGHMEM * ZONES_SHIFT) \
+ | (OPT_ZONE_DMA32 << __GFP_DMA32 * ZONES_SHIFT) \
+ | (ZONE_NORMAL << __GFP_MOVABLE * ZONES_SHIFT) \
+ | (OPT_ZONE_DMA << (__GFP_MOVABLE | __GFP_DMA) * ZONES_SHIFT) \
+ | (ZONE_MOVABLE << (__GFP_MOVABLE | __GFP_HIGHMEM) * ZONES_SHIFT)\
+ | (OPT_ZONE_DMA32 << (__GFP_MOVABLE | __GFP_DMA32) * ZONES_SHIFT)\
+)
+
+/*
+ * GFP_ZONE_BAD is a bitmap for all combination of __GFP_DMA, __GFP_DMA32
+ * __GFP_HIGHMEM and __GFP_MOVABLE that are not permitted. One flag per
+ * entry starting with bit 0. Bit is set if the combination is not
+ * allowed.
+ */
+#define GFP_ZONE_BAD ( \
+ 1 << (__GFP_DMA | __GFP_HIGHMEM) \
+ | 1 << (__GFP_DMA | __GFP_DMA32) \
+ | 1 << (__GFP_DMA32 | __GFP_HIGHMEM) \
+ | 1 << (__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM) \
+ | 1 << (__GFP_MOVABLE | __GFP_HIGHMEM | __GFP_DMA) \
+ | 1 << (__GFP_MOVABLE | __GFP_DMA32 | __GFP_DMA) \
+ | 1 << (__GFP_MOVABLE | __GFP_DMA32 | __GFP_HIGHMEM) \
+ | 1 << (__GFP_MOVABLE | __GFP_DMA32 | __GFP_DMA | __GFP_HIGHMEM)\
+)
+
+static inline enum zone_type gfp_zone(gfp_t flags)
+{
+ enum zone_type z;
+ int bit = flags & GFP_ZONEMASK;
+
+ z = (GFP_ZONE_TABLE >> (bit * ZONES_SHIFT)) &
+ ((1 << ZONES_SHIFT) - 1);
+
+ if (__builtin_constant_p(bit))
+ BUILD_BUG_ON((GFP_ZONE_BAD >> bit) & 1);
+ else {
+#ifdef CONFIG_DEBUG_VM
+ BUG_ON((GFP_ZONE_BAD >> bit) & 1);
#endif
- return ZONE_NORMAL;
+ }
+ return z;
}
/*