[RFC][PATCH] slab: fix caller tracking on CONFIG_OPTIMIZE_INLINING.

[Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>]

If CONFIG_OPTIMIZE_INLINING=y, /proc/slab_allocators shows entries like

  size-512: 5 kzalloc+0xb/0x10
  size-256: 31 kzalloc+0xb/0x10

which are useless for debugging.
Use "__always_inline" rather than "inline" in order to make
/proc/slab_allocators show caller of kzalloc() if caller tracking is enabled.

Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
----------
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 573c809..2b745c0 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -188,6 +188,18 @@ size_t ksize(const void *);
 #else
 #include <linux/slab_def.h>
 #endif
+/*
+ * /proc/slab_allocator needs _RET_IP_ value. If CONFIG_OPTIMIZE_INLINING=y,
+ * use of "inline" causes compilers to pass address of kzalloc() etc. rather
+ * than address of caller. Thus, use "__always_inline" if _RET_IP_ value is
+ * needed.
+ */
+#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
+	(defined(CONFIG_SLAB) && defined(CONFIG_TRACING))
+#define slabtrace_inline __always_inline
+#else
+#define slabtrace_inline inline
+#endif
 
 /**
  * kcalloc - allocate memory for an array. The memory is set to zero.
@@ -240,7 +252,7 @@ size_t ksize(const void *);
  * for general use, and so are not documented here. For a full list of
  * potential flags, always refer to linux/gfp.h.
  */
-static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
+static slabtrace_inline void *kcalloc(size_t n, size_t size, gfp_t flags)
 {
 	if (size != 0 && n > ULONG_MAX / size)
 		return NULL;
@@ -258,19 +270,19 @@ static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
  * if available. Equivalent to kmalloc() in the non-NUMA single-node
  * case.
  */
-static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
+static slabtrace_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 {
 	return kmalloc(size, flags);
 }
 
-static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
+static slabtrace_inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
 {
 	return __kmalloc(size, flags);
 }
 
 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 
-static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
+static slabtrace_inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
 					gfp_t flags, int node)
 {
 	return kmem_cache_alloc(cachep, flags);
@@ -325,7 +337,7 @@ extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
 /*
  * Shortcuts
  */
-static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
+static slabtrace_inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
 {
 	return kmem_cache_alloc(k, flags | __GFP_ZERO);
 }
@@ -335,7 +347,7 @@ static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
  * @size: how many bytes of memory are required.
  * @flags: the type of memory to allocate (see kmalloc).
  */
-static inline void *kzalloc(size_t size, gfp_t flags)
+static slabtrace_inline void *kzalloc(size_t size, gfp_t flags)
 {
 	return kmalloc(size, flags | __GFP_ZERO);
 }
@@ -346,7 +358,7 @@ static inline void *kzalloc(size_t size, gfp_t flags)
  * @flags: the type of memory to allocate (see kmalloc).
  * @node: memory node from which to allocate
  */
-static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
+static slabtrace_inline void *kzalloc_node(size_t size, gfp_t flags, int node)
 {
 	return kmalloc_node(size, flags | __GFP_ZERO, node);
 }

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