diff options
author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2014-01-10 12:41:00 +1100 |
---|---|---|
committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2014-01-10 12:41:00 +1100 |
commit | 8ec7622a12051ce53f65bce670e8d02a684353e9 (patch) | |
tree | 70847cc9ad527644abac255755854320c402c85c /init | |
parent | 99dad6c97e4fc2398eeca18e4a39eda3e9ea6ca6 (diff) |
mm: create a separate slab for page->ptl allocation
If DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC are enabled spinlock_t on x86_64 is
72 bytes. For page->ptl they will be allocated from kmalloc-96 slab, so
we loose 24 on each. An average system can easily allocate few tens
thousands of page->ptl and overhead is significant.
Let's create a separate slab for page->ptl allocation to solve this.
To make sure that it really works this time, some numbers from my test
machine (just booted, no load):
Before:
# grep '^\(kmalloc-96\|page->ptl\)' /proc/slabinfo
kmalloc-96 31987 32190 128 30 1 : tunables 120 60 8 : slabdata 1073 1073 92
After:
# grep '^\(kmalloc-96\|page->ptl\)' /proc/slabinfo
page->ptl 27516 28143 72 53 1 : tunables 120 60 8 : slabdata 531 531 9
kmalloc-96 3853 5280 128 30 1 : tunables 120 60 8 : slabdata 176 176 0
Note that the patch is useful not only for debug case, but also for
PREEMPT_RT, where spinlock_t is always bloated.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'init')
-rw-r--r-- | init/main.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/init/main.c b/init/main.c index febc511e078a..01573fdfa186 100644 --- a/init/main.c +++ b/init/main.c @@ -476,7 +476,7 @@ static void __init mm_init(void) mem_init(); kmem_cache_init(); percpu_init_late(); - pgtable_cache_init(); + pgtable_init(); vmalloc_init(); } |