android_kernel_xiaomi_sm8350/mm
Zachary Amsden a600388d28 [PATCH] x86: ptep_clear optimization
Add a new accessor for PTEs, which passes the full hint from the mmu_gather
struct; this allows architectures with hardware pagetables to optimize away
atomic PTE operations when destroying an address space.  Removing the
locked operation should allow better pipelining of memory access in this
loop.  I measured an average savings of 30-35 cycles per zap_pte_range on
the first 500 destructions on Pentium-M, but I believe the optimization
would win more on older processors which still assert the bus lock on xchg
for an exclusive cacheline.

Update: I made some new measurements, and this saves exactly 26 cycles over
ptep_get_and_clear on Pentium M.  On P4, with a PAE kernel, this saves 180
cycles per ptep_get_and_clear, for a whopping 92160 cycles savings for a
full address space destruction.

pte_clear_full is not yet used, but is provided for future optimizations
(in particular, when running inside of a hypervisor that queues page table
updates, the full hint allows us to avoid queueing unnecessary page table
update for an address space in the process of being destroyed.

This is not a huge win, but it does help a bit, and sets the stage for
further hypervisor optimization of the mm layer on all architectures.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Cc: Christoph Lameter <christoph@lameter.com>
Cc: <linux-mm@kvack.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-05 00:05:48 -07:00
..
bootmem.c [PATCH] Use ALIGN to remove duplicate code 2005-06-25 16:25:02 -07:00
fadvise.c [PATCH] xip: madvice/fadvice: execute in place 2005-06-24 00:06:42 -07:00
filemap_xip.c [PATCH] execute-in-place fixes 2005-07-15 09:54:50 -07:00
filemap.c [PATCH] shmem_populate: avoid an useless check, and some comments 2005-09-05 00:05:45 -07:00
filemap.h [PATCH] xip: reduce code duplication 2005-06-24 00:06:41 -07:00
fremap.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
highmem.c [PATCH] count bounce buffer pages in vmstat 2005-05-01 08:58:37 -07:00
hugetlb.c [PATCH] hugetlb: move stale pte check into huge_pte_alloc() 2005-09-05 00:05:46 -07:00
internal.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
Kconfig [PATCH] sparsemem extreme implementation 2005-09-05 00:05:38 -07:00
madvise.c [PATCH] mm: fix madvise vma merging 2005-09-05 00:05:44 -07:00
Makefile [PATCH] xip: fs/mm: execute in place 2005-06-24 00:06:41 -07:00
memory.c [PATCH] x86: ptep_clear optimization 2005-09-05 00:05:48 -07:00
mempolicy.c [PATCH] /proc/<pid>/numa_maps to show on which nodes pages reside 2005-09-05 00:05:43 -07:00
mempool.c [PATCH] propagate __nocast annotations 2005-07-07 18:23:46 -07:00
mincore.c [PATCH] freepgt: sys_mincore ignore FIRST_USER_PGD_NR 2005-04-19 13:29:20 -07:00
mlock.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mmap.c [PATCH] __vm_enough_memory() signedness fix 2005-08-04 21:43:14 -07:00
mprotect.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mremap.c [PATCH] mm: remap ZERO_PAGE mappings 2005-09-05 00:05:44 -07:00
msync.c [PATCH] msync: check pte dirty earlier 2005-06-21 18:46:21 -07:00
nommu.c [PATCH] __vm_enough_memory() signedness fix 2005-08-04 21:43:14 -07:00
oom_kill.c [PATCH] mm: quieten OOM killer noise 2005-07-07 18:23:36 -07:00
page_alloc.c [PATCH] VM: zone reclaim atomic ops cleanup 2005-09-05 00:05:44 -07:00
page_io.c [PATCH] swsusp: kill config_pm_disk 2005-06-25 16:24:32 -07:00
page-writeback.c [PATCH] rename wakeup_bdflush to wakeup_pdflush 2005-06-28 21:20:31 -07:00
pdflush.c [PATCH] Cleanup patch for process freezing 2005-06-25 17:10:13 -07:00
prio_tree.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
readahead.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
rmap.c [PATCH] mm: cleanup rmap 2005-09-05 00:05:43 -07:00
shmem.c [PATCH] shmem_populate: avoid an useless check, and some comments 2005-09-05 00:05:45 -07:00
slab.c [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
sparse.c [PATCH] sparsemem extreme: hotplug preparation 2005-09-05 00:05:38 -07:00
swap_state.c [PATCH] delete from_swap_cache BUG_ONs 2005-09-05 00:05:42 -07:00
swap.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
swapfile.c [PATCH] swap: swap_lock replace list+device 2005-09-05 00:05:42 -07:00
thrash.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
tiny-shmem.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
truncate.c [PATCH] DocBook: fix some descriptions 2005-05-01 08:59:26 -07:00
vmalloc.c [PATCH] arm: allow for arch-specific IOREMAP_MAX_ORDER 2005-09-05 00:05:46 -07:00
vmscan.c [PATCH] VM: zone reclaim atomic ops cleanup 2005-09-05 00:05:44 -07:00