The patch titled
Subject: mm, page_alloc: move __GFP_HARDWALL modifications out of the fastpath
has been added to the -mm tree. Its filename is
mm-page_alloc-move-__gfp_hardwall-modifications-out-of-the-fastpath.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-move-__gfp_hardwall-modifications-out-of-the-fastpath.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-move-__gfp_hardwall-modifications-out-of-the-fastpath.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Subject: mm, page_alloc: move __GFP_HARDWALL modifications out of the fastpath
__GFP_HARDWALL only has meaning in the context of cpusets but the fast
path always applies the flag on the first attempt. Move the manipulations
into the cpuset paths where they will be masked by a static branch in the
common case.
With the other micro-optimisations in this series combined, the impact on
a page allocator microbenchmark is
4.6.0-rc2 4.6.0-rc2
decstat-v1r20 micro-v1r20
Min alloc-odr0-1 381.00 ( 0.00%) 377.00 ( 1.05%)
Min alloc-odr0-2 275.00 ( 0.00%) 273.00 ( 0.73%)
Min alloc-odr0-4 229.00 ( 0.00%) 226.00 ( 1.31%)
Min alloc-odr0-8 199.00 ( 0.00%) 196.00 ( 1.51%)
Min alloc-odr0-16 186.00 ( 0.00%) 183.00 ( 1.61%)
Min alloc-odr0-32 179.00 ( 0.00%) 175.00 ( 2.23%)
Min alloc-odr0-64 174.00 ( 0.00%) 172.00 ( 1.15%)
Min alloc-odr0-128 172.00 ( 0.00%) 170.00 ( 1.16%)
Min alloc-odr0-256 181.00 ( 0.00%) 183.00 ( -1.10%)
Min alloc-odr0-512 193.00 ( 0.00%) 191.00 ( 1.04%)
Min alloc-odr0-1024 201.00 ( 0.00%) 199.00 ( 1.00%)
Min alloc-odr0-2048 206.00 ( 0.00%) 204.00 ( 0.97%)
Min alloc-odr0-4096 212.00 ( 0.00%) 210.00 ( 0.94%)
Min alloc-odr0-8192 215.00 ( 0.00%) 213.00 ( 0.93%)
Min alloc-odr0-16384 216.00 ( 0.00%) 214.00 ( 0.93%)
Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff -puN mm/page_alloc.c~mm-page_alloc-move-__gfp_hardwall-modifications-out-of-the-fastpath mm/page_alloc.c
--- a/mm/page_alloc.c~mm-page_alloc-move-__gfp_hardwall-modifications-out-of-the-fastpath
+++ a/mm/page_alloc.c
@@ -3379,7 +3379,7 @@ __alloc_pages_nodemask(gfp_t gfp_mask, u
struct page *page = NULL;
unsigned int cpuset_mems_cookie;
unsigned int alloc_flags = ALLOC_WMARK_LOW|ALLOC_FAIR;
- gfp_t alloc_mask; /* The gfp_t that was actually used for allocation */
+ gfp_t alloc_mask = gfp_mask; /* The gfp_t that was actually used for allocation */
struct alloc_context ac = {
.high_zoneidx = gfp_zone(gfp_mask),
.zonelist = zonelist,
@@ -3388,6 +3388,7 @@ __alloc_pages_nodemask(gfp_t gfp_mask, u
};
if (cpusets_enabled()) {
+ alloc_mask |= __GFP_HARDWALL;
alloc_flags |= ALLOC_CPUSET;
if (!ac.nodemask)
ac.nodemask = &cpuset_current_mems_allowed;
@@ -3415,7 +3416,6 @@ retry_cpuset:
ac.classzone_idx = zonelist_zone_idx(preferred_zoneref);
/* First allocation attempt */
- alloc_mask = gfp_mask|__GFP_HARDWALL;
page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac);
if (unlikely(!page)) {
/*
@@ -3440,8 +3440,10 @@ retry_cpuset:
* the mask is being updated. If a page allocation is about to fail,
* check if the cpuset changed during allocation and if so, retry.
*/
- if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
+ if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie))) {
+ alloc_mask = gfp_mask;
goto retry_cpuset;
+ }
return page;
}
_
Patches currently in -mm which might be from mgorman@xxxxxxxxxxxxxxxxxxx are
mm-page_alloc-only-check-pagecompound-for-high-order-pages.patch
mm-page_alloc-use-new-pageanonhead-helper-in-the-free-page-fast-path.patch
mm-page_alloc-reduce-branches-in-zone_statistics.patch
mm-page_alloc-inline-zone_statistics.patch
mm-page_alloc-inline-the-fast-path-of-the-zonelist-iterator.patch
mm-page_alloc-use-__dec_zone_state-for-order-0-page-allocation.patch
mm-page_alloc-avoid-unnecessary-zone-lookups-during-pageblock-operations.patch
mm-page_alloc-convert-alloc_flags-to-unsigned.patch
mm-page_alloc-convert-nr_fair_skipped-to-bool.patch
mm-page_alloc-remove-unnecessary-local-variable-in-get_page_from_freelist.patch
mm-page_alloc-remove-unnecessary-initialisation-in-get_page_from_freelist.patch
mm-page_alloc-remove-redundant-check-for-empty-zonelist.patch
mm-page_alloc-simplify-last-cpupid-reset.patch
mm-page_alloc-move-might_sleep_if-check-to-the-allocator-slowpath.patch
mm-page_alloc-move-__gfp_hardwall-modifications-out-of-the-fastpath.patch
mm-page_alloc-check-once-if-a-zone-has-isolated-pageblocks.patch
mm-page_alloc-shorten-the-page-allocator-fast-path.patch
mm-page_alloc-reduce-cost-of-fair-zone-allocation-policy-retry.patch
mm-page_alloc-shortcut-watermark-checks-for-order-0-pages.patch
mm-page_alloc-avoid-looking-up-the-first-zone-in-a-zonelist-twice.patch
mm-page_alloc-remove-field-from-alloc_context.patch
mm-page_alloc-check-multiple-page-fields-with-a-single-branch.patch
mm-page_alloc-remove-unnecessary-variable-from-free_pcppages_bulk.patch
mm-page_alloc-inline-pageblock-lookup-in-page-free-fast-paths.patch
mm-page_alloc-defer-debugging-checks-of-freed-pages-until-a-pcp-drain.patch
mm-page_alloc-defer-debugging-checks-of-pages-allocated-from-the-pcp.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
