The patch titled
Subject: mm/slub.c: pack red_left_pad with another int to save a word
has been added to the -mm tree. Its filename is
mm-slub-pack-red_left_pad-with-another-int-to-save-a-word.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-slub-pack-red_left_pad-with-another-int-to-save-a-word.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-slub-pack-red_left_pad-with-another-int-to-save-a-word.patch
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From: Wei Yang <richard.weiyang@xxxxxxxxx>
Subject: mm/slub.c: pack red_left_pad with another int to save a word
Patch series " try to save some memory for kmem_cache in some cases", v2.
kmem_cache is a frequently used data in kernel. During the code reading,
I found maybe we could save some space in some cases.
1. On 64bit arch, type int will occupy a word if it doesn't sit well.
2. cpu_slab->partial is just used when CONFIG_SLUB_CPU_PARTIAL is set
3. cpu_partial is just used when CONFIG_SLUB_CPU_PARTIAL is set, while
just save some space on 32bit arch.
This patch (of 3):
On 64bit arch, struct is 8-bytes aligned, so int will occupy a word if it
doesn't sit well.
This patch pack red_left_pad with reserved to save 8 bytes for struct
kmem_cache on a 64bit arch.
Link: http://lkml.kernel.org/r/20170502144533.10729-2-richard.weiyang@xxxxxxxxx
Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/slub_def.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN include/linux/slub_def.h~mm-slub-pack-red_left_pad-with-another-int-to-save-a-word include/linux/slub_def.h
--- a/include/linux/slub_def.h~mm-slub-pack-red_left_pad-with-another-int-to-save-a-word
+++ a/include/linux/slub_def.h
@@ -79,9 +79,9 @@ struct kmem_cache {
int inuse; /* Offset to metadata */
int align; /* Alignment */
int reserved; /* Reserved bytes at the end of slabs */
+ int red_left_pad; /* Left redzone padding size */
const char *name; /* Name (only for display!) */
struct list_head list; /* List of slab caches */
- int red_left_pad; /* Left redzone padding size */
#ifdef CONFIG_SYSFS
struct kobject kobj; /* For sysfs */
#endif
_
Patches currently in -mm which might be from richard.weiyang@xxxxxxxxx are
mm-slub-remove-a-redundant-assignment-in-___slab_alloc.patch
mm-slub-reset-cpu_slabs-pointer-in-deactivate_slab.patch
mm-slub-pack-red_left_pad-with-another-int-to-save-a-word.patch
mm-slub-wrap-cpu_slab-partial-in-config_slub_cpu_partial.patch
mm-slub-wrap-kmem_cache-cpu_partial-in-config-config_slub_cpu_partial.patch
mm-page_alloc-return-0-in-case-this-node-has-no-page-within-the-zone.patch
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