Waiman Long f8303c2582 mm, thp: move invariant bug check out of loop in __split_huge_page_map ... In __split_huge_page_map(), the check for page_mapcount(page) is invariant within the for loop. Because of the fact that the macro is implemented using atomic_read(), the redundant check cannot be optimized away by the compiler leading to unnecessary read to the page structure. This patch moves the invariant bug check out of the loop so that it will be done only once. On a 3.16-rc1 based kernel, the execution time of a microbenchmark that broke up 1000 transparent huge pages using munmap() had an execution time of 38,245us and 38,548us with and without the patch respectively. The performance gain is about 1%. Signed-off-by: Waiman Long <Waiman.Long@hp.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Scott J Norton <scott.norton@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2014-08-06 18:01:16 -07:00
..
backing-dev.c	arch: Mass conversion of smp_mb__*()	2014-04-18 14:20:48 +02:00
balloon_compaction.c	mm: print more details for bad_page()	2014-01-23 16:36:50 -08:00
bootmem.c	mm/bootmem.c: remove unused local `map'	2013-11-13 12:09:09 +09:00
cleancache.c	mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE	2014-01-23 16:36:50 -08:00
cma.c	mm, CMA: clean-up log message	2014-08-06 18:01:16 -07:00
compaction.c	mm, compaction: properly signal and act upon lock and need_sched() contention	2014-06-04 16:54:11 -07:00
debug-pagealloc.c
dmapool.c	mm/dmapool.c: reuse devres_release() to free resources	2014-06-04 16:54:08 -07:00
early_ioremap.c	mm: create generic early_ioremap() support	2014-04-07 16:36:15 -07:00
fadvise.c	teach SYSCALL_DEFINE<n> how to deal with long long/unsigned long long	2013-03-03 22:46:22 -05:00
failslab.c
filemap_xip.c	seqcount: Add lockdep functionality to seqcount/seqlock structures	2013-11-06 12:40:26 +01:00
filemap.c	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-08-04 16:23:30 -07:00
fremap.c	mm: mark remap_file_pages() syscall as deprecated	2014-06-06 16:08:17 -07:00
frontswap.c	swap: change swap_list_head to plist, add swap_avail_head	2014-06-04 16:54:07 -07:00
gup.c	mm: cleanup __get_user_pages()	2014-06-04 16:54:05 -07:00
highmem.c
huge_memory.c	mm, thp: move invariant bug check out of loop in __split_huge_page_map	2014-08-06 18:01:16 -07:00
hugetlb_cgroup.c	cgroup: replace cgroup_add_cftypes() with cgroup_add_legacy_cftypes()	2014-07-15 11:05:09 -04:00
hugetlb.c	kexec: export free_huge_page to VMCOREINFO	2014-07-30 17:16:13 -07:00
hwpoison-inject.c	mm/hwpoison: add '#' to hwpoison_inject	2014-01-21 16:19:48 -08:00
init-mm.c
internal.h	mm/internal.h: use nth_page	2014-08-06 18:01:16 -07:00
interval_tree.c
iov_iter.c	bio_vec-backed iov_iter	2014-05-06 17:39:45 -04:00
Kconfig	CMA: generalize CMA reserved area management functionality	2014-08-06 18:01:16 -07:00
Kconfig.debug
kmemcheck.c
kmemleak-test.c	mm/kmemleak-test.c: use pr_fmt for logging	2014-06-06 16:08:18 -07:00
kmemleak.c	mm: introduce kmemleak_update_trace()	2014-06-06 16:08:17 -07:00
ksm.c	sched: Remove proliferation of wait_on_bit() action functions	2014-07-16 15:10:39 +02:00
list_lru.c	mm: keep page cache radix tree nodes in check	2014-04-03 16:21:01 -07:00
maccess.c
madvise.c	mm: madvise: fix MADV_WILLNEED on shmem swapouts	2014-05-23 09:37:29 -07:00
Makefile	CMA: generalize CMA reserved area management functionality	2014-08-06 18:01:16 -07:00
memblock.c	mm/memblock.c: call kmemleak directly from memblock_(alloc|free)	2014-06-06 16:08:17 -07:00
memcontrol.c	Merge branch 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2014-08-04 10:11:28 -07:00
memory_hotplug.c	mem-hotplug: introduce MMOP_OFFLINE to replace the hard coding -1	2014-08-06 18:01:16 -07:00
memory-failure.c	hwpoison: call action_result() in failure path of hwpoison_user_mappings()	2014-07-30 17:16:13 -07:00
memory.c	mm/memory.c: use entry = ACCESS_ONCE(*pte) in handle_pte_fault()	2014-08-06 18:01:15 -07:00
mempolicy.c	Merge branch 'for-3.16-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2014-07-10 11:38:23 -07:00
mempool.c	mm/mempool.c: update the kmemleak stack trace for mempool allocations	2014-06-06 16:08:17 -07:00
migrate.c	mm: fix direct reclaim writeback regression	2014-07-26 14:38:50 -07:00
mincore.c	mm + fs: prepare for non-page entries in page cache radix trees	2014-04-03 16:21:00 -07:00
mlock.c	mm: try_to_unmap_cluster() should lock_page() before mlocking	2014-04-07 16:35:57 -07:00
mm_init.c	mm: bring back /sys/kernel/mm	2014-01-27 21:02:39 -08:00
mmap.c	mm: convert some level-less printks to pr_*	2014-06-06 16:08:18 -07:00
mmu_context.c	sched/mm: call finish_arch_post_lock_switch in idle_task_exit and use_mm	2014-02-21 08:50:17 +01:00
mmu_notifier.c	mm: audit/fix non-modular users of module_init in core code	2014-01-23 16:36:52 -08:00
mmzone.c	mm: numa: Change page last {nid,pid} into {cpu,pid}	2013-10-09 14:47:45 +02:00
mprotect.c	mm: move mmu notifier call from change_protection to change_pmd_range	2014-04-07 16:35:50 -07:00
mremap.c	mm, thp: close race between mremap() and split_huge_page()	2014-05-11 17:55:48 +09:00
msync.c	msync: fix incorrect fstart calculation	2014-07-03 09:21:53 -07:00
nobootmem.c	mm/memblock.c: call kmemleak directly from memblock_(alloc|free)	2014-06-06 16:08:17 -07:00
nommu.c	mm: nommu: per-thread vma cache fix	2014-06-23 16:47:43 -07:00
oom_kill.c	mm, oom: base root bonus on current usage	2014-01-30 16:56:56 -08:00
page_alloc.c	mm: page_alloc: simplify drain_zone_pages by using min()	2014-08-06 18:01:16 -07:00
page_cgroup.c	mm/page_cgroup.c: mark functions as static	2014-04-03 16:21:02 -07:00
page_io.c	fix __swap_writepage() compile failure on old gcc versions	2014-06-14 19:30:48 -05:00
page_isolation.c	mm: memory-hotplug: enable memory hotplug to handle hugepage	2013-09-11 15:57:48 -07:00
page-writeback.c	mm/page-writeback.c: fix divide by zero in bdi_dirty_limits()	2014-07-30 17:16:13 -07:00
pagewalk.c	mm/pagewalk.c: fix walk_page_range() access of wrong PTEs	2013-10-30 14:27:03 -07:00
percpu-km.c
percpu-vm.c
percpu.c	percpu: Use ALIGN macro instead of hand coding alignment calculation	2014-06-19 11:00:27 -04:00
pgtable-generic.c	mm: fix TLB flush race between migration, and change_protection_range	2013-12-18 19:04:51 -08:00
process_vm_access.c	start adding the tag to iov_iter	2014-05-06 17:32:49 -04:00
quicklist.c
readahead.c	mm/readahead.c: remove unused file_ra_state from count_history_pages	2014-08-06 18:01:15 -07:00
rmap.c	mm/rmap.c: fix pgoff calculation to handle hugepage correctly	2014-07-23 15:10:54 -07:00
shmem.c	shmem: fix splicing from a hole while it's punched	2014-07-23 15:10:55 -07:00
slab_common.c	mm: move slab related stuff from util.c to slab_common.c	2014-08-06 18:01:15 -07:00
slab.c	mm/slab.c: fix comments	2014-08-06 18:01:15 -07:00
slab.h	slab: convert last use of __FUNCTION__ to __func__	2014-08-06 18:01:15 -07:00
slob.c	slab: get_online_mems for kmem_cache_{create,destroy,shrink}	2014-06-04 16:53:59 -07:00
slub.c	slab: fix the alias count (via sysfs) of slab cache	2014-08-06 18:01:15 -07:00
sparse-vmemmap.c	mm/sparse: use memblock apis for early memory allocations	2014-01-21 16:19:47 -08:00
sparse.c	mm: use macros from compiler.h instead of __attribute__((...))	2014-04-07 16:35:54 -07:00
swap_state.c	mm: page_alloc: convert hot/cold parameter and immediate callers to bool	2014-06-04 16:54:09 -07:00
swap.c	mm: non-atomically mark page accessed during page cache allocation where possible	2014-06-04 16:54:10 -07:00
swapfile.c	mm/swapfile.c: delete the "last_in_cluster < scan_base" loop in the body of scan_swap_map()	2014-06-04 16:54:12 -07:00
truncate.c	mm/fs: fix pessimization in hole-punching pagecache	2014-07-23 15:10:55 -07:00
util.c	mm: move slab related stuff from util.c to slab_common.c	2014-08-06 18:01:15 -07:00
vmacache.c	mm,vmacache: optimize overflow system-wide flushing	2014-06-04 16:53:57 -07:00
vmalloc.c	vmalloc: use rcu list iterator to reduce vmap_area_lock contention	2014-08-06 18:01:15 -07:00
vmpressure.c	arm, pm, vmpressure: add missing slab.h includes	2014-02-03 13:24:01 -05:00
vmscan.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2014-06-12 10:30:18 -07:00
vmstat.c	mm: use the light version __mod_zone_page_state in mlocked_vma_newpage()	2014-06-04 16:54:07 -07:00
workingset.c	mm: keep page cache radix tree nodes in check	2014-04-03 16:21:01 -07:00
zbud.c	mm/zbud.c: make size unsigned like unique callsite	2014-06-04 16:54:13 -07:00
zsmalloc.c	zsmalloc: fixup trivial zs size classes value in comments	2014-06-04 16:54:13 -07:00
zswap.c	mm/zswap: NUMA aware allocation for zswap_dstmem	2014-06-04 16:54:14 -07:00