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authorVegard Nossum <vegard.nossum@gmail.com>2008-05-31 17:56:17 +0400
committerVegard Nossum <vegard.nossum@gmail.com>2009-06-15 14:40:03 +0400
commit2dff440525f8faba8836e9f05297b76f23b4af30 (patch)
tree9f15e1dc2da06dba97cd939e41f34342caf05097 /include/linux/gfp.h
parentf85612967c93b67b10dd240e3e8bf8a0eee9def7 (diff)
downloadlinux-2dff440525f8faba8836e9f05297b76f23b4af30.tar.xz
kmemcheck: add mm functions
With kmemcheck enabled, the slab allocator needs to do this: 1. Tell kmemcheck to allocate the shadow memory which stores the status of each byte in the allocation proper, e.g. whether it is initialized or uninitialized. 2. Tell kmemcheck which parts of memory that should be marked uninitialized. There are actually a few more states, such as "not yet allocated" and "recently freed". If a slab cache is set up using the SLAB_NOTRACK flag, it will never return memory that can take page faults because of kmemcheck. If a slab cache is NOT set up using the SLAB_NOTRACK flag, callers can still request memory with the __GFP_NOTRACK flag. This does not prevent the page faults from occuring, however, but marks the object in question as being initialized so that no warnings will ever be produced for this object. In addition to (and in contrast to) __GFP_NOTRACK, the __GFP_NOTRACK_FALSE_POSITIVE flag indicates that the allocation should not be tracked _because_ it would produce a false positive. Their values are identical, but need not be so in the future (for example, we could now enable/disable false positives with a config option). Parts of this patch were contributed by Pekka Enberg but merged for atomicity. Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Ingo Molnar <mingo@elte.hu> [rebased for mainline inclusion] Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Diffstat (limited to 'include/linux/gfp.h')
-rw-r--r--include/linux/gfp.h9
1 files changed, 8 insertions, 1 deletions
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 0bbc15f54536..daeaa8fe1bbd 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -51,8 +51,15 @@ struct vm_area_struct;
#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_NOTRACK ((__force gfp_t)0x200000u) /* Don't track with kmemcheck */
-#define __GFP_BITS_SHIFT 21 /* Room for 21 __GFP_FOO bits */
+/*
+ * 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 22 /* Room for 22 __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 */