diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2015-11-06 16:29:50 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-11-06 17:50:42 -0800 |
| commit | f1e61557f0230d51a3df8d825f2c156e75563bff (patch) | |
| tree | a62bd2c7d3df2b5632b667a46b55cd928dce8002 /include/linux/mm_types.h | |
| parent | 32e7ba1ea1f8d1f0ea4983e768f8b566770a55b3 (diff) | |
mm: pack compound_dtor and compound_order into one word in struct page
The patch halves space occupied by compound_dtor and compound_order in
struct page.
For compound_order, it's trivial long -> short conversion.
For get_compound_page_dtor(), we now use hardcoded table for destructor
lookup and store its index in the struct page instead of direct pointer
to destructor. It shouldn't be a big trouble to maintain the table: we
have only two destructor and NULL currently.
This patch free up one word in tail pages for reuse. This is preparation
for the next patch.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/mm_types.h')
| -rw-r--r-- | include/linux/mm_types.h | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index c0ec46df6c13..e334ef79cb43 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -28,8 +28,6 @@ struct mem_cgroup; IS_ENABLED(CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK)) #define ALLOC_SPLIT_PTLOCKS (SPINLOCK_SIZE > BITS_PER_LONG/8) -typedef void compound_page_dtor(struct page *); - /* * Each physical page in the system has a struct page associated with * it to keep track of whatever it is we are using the page for at the @@ -136,8 +134,8 @@ struct page { */ /* First tail page of compound page */ struct { - compound_page_dtor *compound_dtor; - unsigned long compound_order; + unsigned short int compound_dtor; + unsigned short int compound_order; }; #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS |