From d3111e6cce6001e71ddc4737d0d412c2300043a2 Mon Sep 17 00:00:00 2001 From: Wei Yang Date: Thu, 6 Jul 2017 15:36:28 -0700 Subject: [PATCH] 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@gmail.com Signed-off-by: Wei Yang Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/slub_def.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h index 93315d6..070ff84 100644 --- a/include/linux/slub_def.h +++ b/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 */ struct work_struct kobj_remove_work; -- 2.7.4