Extract the code to do object alignment from the allocators.
Do the alignment calculations in slab_common so that the
__kmem_cache_create functions of the allocators do not have
to deal with alignment.
Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
---
mm/slab.c | 22 +---------------------
mm/slab.h | 3 +++
mm/slab_common.c | 30 +++++++++++++++++++++++++++++-
mm/slob.c | 11 -----------
mm/slub.c | 45 ++++++++-------------------------------------
5 files changed, 41 insertions(+), 70 deletions(-)
Index: linux-2.6/mm/slab.c
===================================================================
--- linux-2.6.orig/mm/slab.c 2012-08-01 15:57:38.187184829 -0500
+++ linux-2.6/mm/slab.c 2012-08-01 15:58:51.272511065 -0500
@@ -2377,22 +2377,6 @@
cachep->size &= ~(BYTES_PER_WORD - 1);
}
- /* calculate the final buffer alignment: */
-
- /* 1) arch recommendation: can be overridden for debug */
- if (flags & SLAB_HWCACHE_ALIGN) {
- /*
- * Default alignment: as specified by the arch code. Except if
- * an object is really small, then squeeze multiple objects into
- * one cacheline.
- */
- ralign = cache_line_size();
- while (cachep->size <= ralign / 2)
- ralign /= 2;
- } else {
- ralign = BYTES_PER_WORD;
- }
-
/*
* Redzoning and user store require word alignment or possibly larger.
* Note this will be overridden by architecture or caller mandated
@@ -2409,10 +2393,6 @@
cachep->size &= ~(REDZONE_ALIGN - 1);
}
- /* 2) arch mandated alignment */
- if (ralign < ARCH_SLAB_MINALIGN) {
- ralign = ARCH_SLAB_MINALIGN;
- }
/* 3) caller mandated alignment */
if (ralign < cachep->align) {
ralign = cachep->align;
Index: linux-2.6/mm/slab_common.c
===================================================================
--- linux-2.6.orig/mm/slab_common.c 2012-08-01 15:58:41.000000000 -0500
+++ linux-2.6/mm/slab_common.c 2012-08-01 15:58:51.272511065 -0500
@@ -25,6 +25,34 @@
struct kmem_cache *kmem_cache;
/*
+ * 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.
+ */
+unsigned long calculate_alignment(unsigned long flags,
+ unsigned long align, unsigned long size)
+{
+ /*
+ * If the user wants hardware cache aligned objects then follow that
+ * suggestion if the object is sufficiently large.
+ *
+ * The hardware cache alignment cannot override the specified
+ * alignment though. If that is greater then use it.
+ */
+ if (flags & SLAB_HWCACHE_ALIGN) {
+ unsigned long ralign = cache_line_size();
+ while (size <= ralign / 2)
+ ralign /= 2;
+ align = max(align, ralign);
+ }
+
+ if (align < ARCH_SLAB_MINALIGN)
+ align = ARCH_SLAB_MINALIGN;
+
+ return ALIGN(align, sizeof(void *));
+}
+
+
+/*
* kmem_cache_create - Create a cache.
* @name: A string which is used in /proc/slabinfo to identify this cache.
* @size: The size of objects to be created in this cache.
@@ -107,7 +135,7 @@
int r;
s->object_size = s->size = size;
- s->align = align;
+ s->align = calculate_alignment(flags, align, size);
s->ctor = ctor;
s->name = kstrdup(name, GFP_KERNEL);
if (!s->name) {
@@ -188,7 +216,7 @@
if (s) {
s->name = name;
s->size = s->object_size = size;
- s->align = ARCH_KMALLOC_MINALIGN;
+ s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size);
r = __kmem_cache_create(s, flags);
if (!r) {
Index: linux-2.6/mm/slob.c
===================================================================
--- linux-2.6.orig/mm/slob.c 2012-08-01 15:57:53.000000000 -0500
+++ linux-2.6/mm/slob.c 2012-08-01 15:59:21.825067980 -0500
@@ -124,7 +124,6 @@
#define SLOB_UNIT sizeof(slob_t)
#define SLOB_UNITS(size) (((size) + SLOB_UNIT - 1)/SLOB_UNIT)
-#define SLOB_ALIGN L1_CACHE_BYTES
/*
* struct slob_rcu is inserted at the tail of allocated slob blocks, which
@@ -510,21 +509,11 @@
int __kmem_cache_create(struct kmem_cache *c, unsigned long flags)
{
- size_t align = c->size;
-
if (flags & SLAB_DESTROY_BY_RCU) {
/* leave room for rcu footer at the end of object */
c->size += sizeof(struct slob_rcu);
}
c->flags = flags;
- /* ignore alignment unless it's forced */
- c->align = (flags & SLAB_HWCACHE_ALIGN) ? SLOB_ALIGN : 0;
- if (c->align < ARCH_SLAB_MINALIGN)
- c->align = ARCH_SLAB_MINALIGN;
- if (c->align < align)
- c->align = align;
-
- kmemleak_alloc(c, sizeof(struct kmem_cache), 1, GFP_KERNEL);
return 0;
}
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2012-08-01 15:57:44.771304427 -0500
+++ linux-2.6/mm/slub.c 2012-08-01 15:58:51.276511157 -0500
@@ -2747,32 +2747,6 @@
return -ENOSYS;
}
-/*
- * Figure out what the alignment of the objects will be.
- */
-static unsigned long calculate_alignment(unsigned long flags,
- unsigned long align, unsigned long size)
-{
- /*
- * If the user wants hardware cache aligned objects then follow that
- * suggestion if the object is sufficiently large.
- *
- * The hardware cache alignment cannot override the specified
- * alignment though. If that is greater then use it.
- */
- if (flags & SLAB_HWCACHE_ALIGN) {
- unsigned long ralign = cache_line_size();
- while (size <= ralign / 2)
- ralign /= 2;
- align = max(align, ralign);
- }
-
- if (align < ARCH_SLAB_MINALIGN)
- align = ARCH_SLAB_MINALIGN;
-
- return ALIGN(align, sizeof(void *));
-}
-
static void
init_kmem_cache_node(struct kmem_cache_node *n)
{
@@ -2906,7 +2880,6 @@
{
unsigned long flags = s->flags;
unsigned long size = s->object_size;
- unsigned long align = s->align;
int order;
/*
@@ -2978,19 +2951,11 @@
#endif
/*
- * Determine the alignment based on various parameters that the
- * user specified and the dynamic determination of cache line size
- * on bootup.
- */
- align = calculate_alignment(flags, align, s->object_size);
- s->align = align;
-
- /*
* SLUB stores one object immediately after another beginning from
* offset 0. In order to align the objects we have to simply size
* each object to conform to the alignment.
*/
- size = ALIGN(size, align);
+ size = ALIGN(size, s->align);
s->size = size;
if (forced_order >= 0)
order = forced_order;
@@ -3019,7 +2984,6 @@
s->max = s->oo;
return !!oo_objects(s->oo);
-
}
static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)
Index: linux-2.6/mm/slab.h
===================================================================
--- linux-2.6.orig/mm/slab.h 2012-08-01 15:56:38.000000000 -0500
+++ linux-2.6/mm/slab.h 2012-08-01 15:58:51.276511157 -0500
@@ -32,6 +32,9 @@
/* The slab cache that manages slab cache information */
extern struct kmem_cache *kmem_cache;
+unsigned long calculate_alignment(unsigned long flags,
+ unsigned long align, unsigned long size);
+
/* Functions provided by the slab allocators */
extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags);
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>