From: Christoph Lameter <cl@linux.com>
To: Joonsoo Kim <js1304@gmail.com>
Cc: Glauber Costa <glommer@parallels.com>,
Pekka Enberg <penberg@kernel.org>,
linux-mm@kvack.org, David Rientjes <rientjes@google.com>
Subject: Common11r [20/20] Common alignment code
Date: Thu, 09 Aug 2012 08:56:43 -0500 [thread overview]
Message-ID: <20120809135636.800621179@linux.com> (raw)
In-Reply-To: 20120809135623.574621297@linux.com
[-- Attachment #1: common_alignment --]
[-- Type: text/plain, Size: 7639 bytes --]
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@linux.com>
---
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 2012-08-08 15:35:59.498657814 -0500
+++ linux-2.6/mm/slab.c 2012-08-08 15:37:08.031043824 -0500
@@ -2368,22 +2368,6 @@ __kmem_cache_create (struct kmem_cache *
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
@@ -2400,10 +2384,6 @@ __kmem_cache_create (struct kmem_cache *
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 2012-08-08 15:29:06.460261997 -0500
+++ linux-2.6/mm/slab_common.c 2012-08-08 15:37:08.031043824 -0500
@@ -25,6 +25,34 @@ DEFINE_MUTEX(slab_mutex);
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.
@@ -100,7 +128,7 @@ struct kmem_cache *kmem_cache_create(con
s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
if (s) {
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) {
@@ -194,7 +222,7 @@ void __init create_boot_cache(struct kme
s->name = name;
s->size = s->object_size = size;
- s->align = ARCH_KMALLOC_MINALIGN;
+ s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size);
err = __kmem_cache_create(s, flags);
if (err)
Index: linux-2.6/mm/slob.c
===================================================================
--- linux-2.6.orig/mm/slob.c 2012-08-08 15:29:06.452261955 -0500
+++ linux-2.6/mm/slob.c 2012-08-08 15:37:08.031043824 -0500
@@ -124,7 +124,6 @@ static inline void clear_slob_page_free(
#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
@@ -510,20 +509,11 @@ EXPORT_SYMBOL(ksize);
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;
-
return 0;
}
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2012-08-08 15:29:06.472262071 -0500
+++ linux-2.6/mm/slub.c 2012-08-08 15:37:08.031043824 -0500
@@ -2747,32 +2747,6 @@ static inline int calculate_order(int si
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 @@ static int calculate_sizes(struct kmem_c
{
unsigned long flags = s->flags;
unsigned long size = s->object_size;
- unsigned long align = s->align;
int order;
/*
@@ -2978,19 +2951,11 @@ static int calculate_sizes(struct kmem_c
#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 @@ static int calculate_sizes(struct kmem_c
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 2012-08-08 15:29:06.436261851 -0500
+++ linux-2.6/mm/slab.h 2012-08-08 15:37:08.031043824 -0500
@@ -32,6 +32,9 @@ extern struct list_head slab_caches;
/* 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);
--
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next prev parent reply other threads:[~2012-08-09 14:22 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-09 13:56 Common11r [00/20] Sl[auo]b: Common code rework V11 Christoph Lameter
2012-08-09 13:56 ` Common11r [01/20] slub: Add debugging to verify correct cache use on kmem_cache_free() Christoph Lameter
2012-08-09 13:56 ` Common11r [02/20] slub: Use kmem_cache for the kmem_cache structure Christoph Lameter
2012-08-09 13:56 ` Common11r [03/20] Rename oops label Christoph Lameter
2012-08-09 13:56 ` Common11r [04/20] Improve error handling in kmem_cache_create Christoph Lameter
2012-08-09 13:56 ` Common11r [05/20] Move list_add() to slab_common.c Christoph Lameter
2012-08-14 18:43 ` JoonSoo Kim
2012-08-14 20:24 ` Christoph Lameter
2012-08-09 13:56 ` Common11r [06/20] Extract a common function for kmem_cache_destroy Christoph Lameter
2012-08-09 13:56 ` Common11r [07/20] Always use the name "kmem_cache" for the slab cache with the kmem_cache structure Christoph Lameter
2012-08-09 13:56 ` Common11r [08/20] Move freeing of kmem_cache structure to common code Christoph Lameter
2012-08-09 13:56 ` Common11r [09/20] Get rid of __kmem_cache_destroy Christoph Lameter
2012-08-09 13:56 ` Common11r [10/20] Move duping of slab name to slab_common.c Christoph Lameter
2012-08-09 13:56 ` Common11r [11/20] Do slab aliasing call from common code Christoph Lameter
2012-08-09 13:56 ` Common11r [12/20] Move sysfs_slab_add to common Christoph Lameter
2012-08-09 13:56 ` Common11r [13/20] Move kmem_cache allocations into common code Christoph Lameter
2012-08-09 13:56 ` Common11r [14/20] Shrink __kmem_cache_create() parameter lists Christoph Lameter
2012-08-09 13:56 ` Common11r [15/20] Move kmem_cache refcounting to common code Christoph Lameter
2012-08-09 13:56 ` Common11r [16/20] slab: Simplify bootstrap Christoph Lameter
2012-08-09 13:56 ` Common11r [17/20] create common functions for boot slab creation Christoph Lameter
2012-08-09 13:56 ` Common11r [18/20] slub: Use a statically allocated kmem_cache boot structure for bootstrap Christoph Lameter
2012-08-09 13:56 ` Common11r [19/20] slab: Use the new create_boot_cache function to simplify bootstrap Christoph Lameter
2012-08-09 13:56 ` Christoph Lameter [this message]
2012-08-14 15:48 ` Common11r [00/20] Sl[auo]b: Common code rework V11 Christoph Lameter
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