mm/slab_common: commonize slab merge logic

Slab merge is good feature to reduce fragmentation.  Now, it is only
applied to SLUB, but, it would be good to apply it to SLAB.  This patch is
preparation step to apply slab merge to SLAB by commonizing slab merge
logic.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index d9a452e8fb9b3bb1f34d89ddaa87cb8dd90b04bd..a126a31dde020c58395e073e630996422116b949 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3158,6 +3158,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
        slram=          [HW,MTD]
 
+       slab_nomerge    [MM]
+                       Disable merging of slabs with similar size. May be
+                       necessary if there is some reason to distinguish
+                       allocs to different slabs. Debug options disable
+                       merging on their own.
+                       For more information see Documentation/vm/slub.txt.
+
        slab_max_order= [MM, SLAB]
                        Determines the maximum allowed order for slabs.
                        A high setting may cause OOMs due to memory
@@ -3193,11 +3200,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        For more information see Documentation/vm/slub.txt.
 
        slub_nomerge    [MM, SLUB]
-                       Disable merging of slabs with similar size. May be
-                       necessary if there is some reason to distinguish
-                       allocs to different slabs. Debug options disable
-                       merging on their own.
-                       For more information see Documentation/vm/slub.txt.
+                       Same with slab_nomerge. This is supported for legacy.
+                       See slab_nomerge for more information.
 
        smart2=         [HW]
                        Format: <io1>[,<io2>[,...,<io8>]]

diff --git a/mm/slab.h b/mm/slab.h
index 6599f2084e80ef4e4e4dcd62abd7078b42efe216..c44d28b60609acaddc2edc5ecebe7b1be510ac97 100644 (file)
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -88,15 +88,30 @@ extern void create_boot_cache(struct kmem_cache *, const char *name,
                        size_t size, unsigned long flags);
 
 struct mem_cgroup;
+
+int slab_unmergeable(struct kmem_cache *s);
+struct kmem_cache *find_mergeable(size_t size, size_t align,
+               unsigned long flags, const char *name, void (*ctor)(void *));
 #ifdef CONFIG_SLUB
 struct kmem_cache *
 __kmem_cache_alias(const char *name, size_t size, size_t align,
                   unsigned long flags, void (*ctor)(void *));
+
+unsigned long kmem_cache_flags(unsigned long object_size,
+       unsigned long flags, const char *name,
+       void (*ctor)(void *));
 #else
 static inline struct kmem_cache *
 __kmem_cache_alias(const char *name, size_t size, size_t align,
                   unsigned long flags, void (*ctor)(void *))
 { return NULL; }
+
+static inline unsigned long kmem_cache_flags(unsigned long object_size,
+       unsigned long flags, const char *name,
+       void (*ctor)(void *))
+{
+       return flags;
+}
 #endif
 
 

diff --git a/mm/slab_common.c b/mm/slab_common.c
index d7d8ffd0c3061336406105d38b2203c8b7cf6650..f206cb10a544a64ed33606fbe6cae26309db87ad 100644 (file)
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -30,6 +30,34 @@ LIST_HEAD(slab_caches);
 DEFINE_MUTEX(slab_mutex);
 struct kmem_cache *kmem_cache;
 
+/*
+ * Set of flags that will prevent slab merging
+ */
+#define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
+               SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
+               SLAB_FAILSLAB)
+
+#define SLAB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
+               SLAB_CACHE_DMA | SLAB_NOTRACK)
+
+/*
+ * Merge control. If this is set then no merging of slab caches will occur.
+ * (Could be removed. This was introduced to pacify the merge skeptics.)
+ */
+static int slab_nomerge;
+
+static int __init setup_slab_nomerge(char *str)
+{
+       slab_nomerge = 1;
+       return 1;
+}
+
+#ifdef CONFIG_SLUB
+__setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
+#endif
+
+__setup("slab_nomerge", setup_slab_nomerge);
+
 /*
  * Determine the size of a slab object
  */
@@ -115,6 +143,69 @@ out:
 }
 #endif
 
+/*
+ * Find a mergeable slab cache
+ */
+int slab_unmergeable(struct kmem_cache *s)
+{
+       if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
+               return 1;
+
+       if (!is_root_cache(s))
+               return 1;
+
+       if (s->ctor)
+               return 1;
+
+       /*
+        * We may have set a slab to be unmergeable during bootstrap.
+        */
+       if (s->refcount < 0)
+               return 1;
+
+       return 0;
+}
+
+struct kmem_cache *find_mergeable(size_t size, size_t align,
+               unsigned long flags, const char *name, void (*ctor)(void *))
+{
+       struct kmem_cache *s;
+
+       if (slab_nomerge || (flags & SLAB_NEVER_MERGE))
+               return NULL;
+
+       if (ctor)
+               return NULL;
+
+       size = ALIGN(size, sizeof(void *));
+       align = calculate_alignment(flags, align, size);
+       size = ALIGN(size, align);
+       flags = kmem_cache_flags(size, flags, name, NULL);
+
+       list_for_each_entry(s, &slab_caches, list) {
+               if (slab_unmergeable(s))
+                       continue;
+
+               if (size > s->size)
+                       continue;
+
+               if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME))
+                       continue;
+               /*
+                * Check if alignment is compatible.
+                * Courtesy of Adrian Drzewiecki
+                */
+               if ((s->size & ~(align - 1)) != s->size)
+                       continue;
+
+               if (s->size - size >= sizeof(void *))
+                       continue;
+
+               return s;
+       }
+       return NULL;
+}
+
 /*
  * Figure out what the alignment of the objects will be given a set of
  * flags, a user specified alignment and the size of the objects.

diff --git a/mm/slub.c b/mm/slub.c
index 1050d7db57342d55450108c85c71dacb20cf1986..ae7b9f1ad394ca9c65350dac175efa8cab199771 100644 (file)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -169,16 +169,6 @@ static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
  */
 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
 
-/*
- * Set of flags that will prevent slab merging
- */
-#define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
-               SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
-               SLAB_FAILSLAB)
-
-#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
-               SLAB_CACHE_DMA | SLAB_NOTRACK)
-
 #define OO_SHIFT       16
 #define OO_MASK                ((1 << OO_SHIFT) - 1)
 #define MAX_OBJS_PER_PAGE      32767 /* since page.objects is u15 */
@@ -1176,7 +1166,7 @@ out:
 
 __setup("slub_debug", setup_slub_debug);
 
-static unsigned long kmem_cache_flags(unsigned long object_size,
+unsigned long kmem_cache_flags(unsigned long object_size,
        unsigned long flags, const char *name,
        void (*ctor)(void *))
 {
@@ -1208,7 +1198,7 @@ static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
                                        struct page *page) {}
 static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
                                        struct page *page) {}
-static inline unsigned long kmem_cache_flags(unsigned long object_size,
+unsigned long kmem_cache_flags(unsigned long object_size,
        unsigned long flags, const char *name,
        void (*ctor)(void *))
 {
@@ -2718,12 +2708,6 @@ static int slub_min_order;
 static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
 static int slub_min_objects;
 
-/*
- * Merge control. If this is set then no merging of slab caches will occur.
- * (Could be removed. This was introduced to pacify the merge skeptics.)
- */
-static int slub_nomerge;
-
 /*
  * Calculate the order of allocation given an slab object size.
  *
@@ -3252,14 +3236,6 @@ static int __init setup_slub_min_objects(char *str)
 
 __setup("slub_min_objects=", setup_slub_min_objects);
 
-static int __init setup_slub_nomerge(char *str)
-{
-       slub_nomerge = 1;
-       return 1;
-}
-
-__setup("slub_nomerge", setup_slub_nomerge);
-
 void *__kmalloc(size_t size, gfp_t flags)
 {
        struct kmem_cache *s;
@@ -3637,69 +3613,6 @@ void __init kmem_cache_init_late(void)
 {
 }
 
-/*
- * Find a mergeable slab cache
- */
-static int slab_unmergeable(struct kmem_cache *s)
-{
-       if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
-               return 1;
-
-       if (!is_root_cache(s))
-               return 1;
-
-       if (s->ctor)
-               return 1;
-
-       /*
-        * We may have set a slab to be unmergeable during bootstrap.
-        */
-       if (s->refcount < 0)
-               return 1;
-
-       return 0;
-}
-
-static struct kmem_cache *find_mergeable(size_t size, size_t align,
-               unsigned long flags, const char *name, void (*ctor)(void *))
-{
-       struct kmem_cache *s;
-
-       if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
-               return NULL;
-
-       if (ctor)
-               return NULL;
-
-       size = ALIGN(size, sizeof(void *));
-       align = calculate_alignment(flags, align, size);
-       size = ALIGN(size, align);
-       flags = kmem_cache_flags(size, flags, name, NULL);
-
-       list_for_each_entry(s, &slab_caches, list) {
-               if (slab_unmergeable(s))
-                       continue;
-
-               if (size > s->size)
-                       continue;
-
-               if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME))
-                       continue;
-               /*
-                * Check if alignment is compatible.
-                * Courtesy of Adrian Drzewiecki
-                */
-               if ((s->size & ~(align - 1)) != s->size)
-                       continue;
-
-               if (s->size - size >= sizeof(void *))
-                       continue;
-
-               return s;
-       }
-       return NULL;
-}
-
 struct kmem_cache *
 __kmem_cache_alias(const char *name, size_t size, size_t align,
                   unsigned long flags, void (*ctor)(void *))