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authorRichard Kennedy <richard@rsk.demon.co.uk>2011-03-22 16:32:50 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-22 17:44:03 -0700
commit481b4bb5e370aa69c1dc276bd08871ec01b41d2a (patch)
tree11a276bc58c2eb9b0a00fe751c3bf81bc3240382
parentcb240452bfc2ae9de7c840dd0fb3f5b33ce03c31 (diff)
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mm: mm_struct: remove 16 bytes of alignment padding on 64 bit builds
Reorder mm_struct to remove 16 bytes of alignment padding on 64 bit builds. On my config this shrinks mm_struct by enough to fit in one fewer cache lines and allows more objects per slab in mm_struct kmem_cache under SLUB. slabinfo before patch :- Sizes (bytes) Slabs -------------------------------- Object : 848 Total : 9 SlabObj: 896 Full : 2 SlabSiz: 16384 Partial: 5 Loss : 48 CpuSlab: 2 Align : 64 Objects: 18 slabinfo after :- Sizes (bytes) Slabs -------------------------------- Object : 832 Total : 7 SlabObj: 832 Full : 2 SlabSiz: 16384 Partial: 3 Loss : 0 CpuSlab: 2 Align : 64 Objects: 19 Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/mm_types.h8
1 files changed, 5 insertions, 3 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 26bc4e2cd27..02aa5619709 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -237,8 +237,9 @@ struct mm_struct {
atomic_t mm_users; /* How many users with user space? */
atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
int map_count; /* number of VMAs */
- struct rw_semaphore mmap_sem;
+
spinlock_t page_table_lock; /* Protects page tables and some counters */
+ struct rw_semaphore mmap_sem;
struct list_head mmlist; /* List of maybe swapped mm's. These are globally strung
* together off init_mm.mmlist, and are protected
@@ -281,6 +282,9 @@ struct mm_struct {
unsigned int token_priority;
unsigned int last_interval;
+ /* How many tasks sharing this mm are OOM_DISABLE */
+ atomic_t oom_disable_count;
+
unsigned long flags; /* Must use atomic bitops to access the bits */
struct core_state *core_state; /* coredumping support */
@@ -313,8 +317,6 @@ struct mm_struct {
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
pgtable_t pmd_huge_pte; /* protected by page_table_lock */
#endif
- /* How many tasks sharing this mm are OOM_DISABLE */
- atomic_t oom_disable_count;
};
/* Future-safe accessor for struct mm_struct's cpu_vm_mask. */