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authorVlastimil Babka <vbabka@suse.cz>2016-05-19 17:14:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-19 19:12:14 -0700
commit002f290627c27068087f6204baec7a334e5a3b48 (patch)
treeed5a013173e28c0bf864de3a05669967cfb74f57 /kernel
parent0b423ca22f95a867f789aab1fe57ee4e378df43b (diff)
downloadlinux-sh-002f290627c27068087f6204baec7a334e5a3b48.tar.gz
cpuset: use static key better and convert to new API
An important function for cpusets is cpuset_node_allowed(), which optimizes on the fact if there's a single root CPU set, it must be trivially allowed. But the check "nr_cpusets() <= 1" doesn't use the cpusets_enabled_key static key the right way where static keys eliminate branching overhead with jump labels. This patch converts it so that static key is used properly. It's also switched to the new static key API and the checking functions are converted to return bool instead of int. We also provide a new variant __cpuset_zone_allowed() which expects that the static key check was already done and they key was enabled. This is needed for get_page_from_freelist() where we want to also avoid the relatively slower check when ALLOC_CPUSET is not set in alloc_flags. The impact on the page allocator microbenchmark is less than expected but the cleanup in itself is worthwhile. 4.6.0-rc2 4.6.0-rc2 multcheck-v1r20 cpuset-v1r20 Min alloc-odr0-1 348.00 ( 0.00%) 348.00 ( 0.00%) Min alloc-odr0-2 254.00 ( 0.00%) 254.00 ( 0.00%) Min alloc-odr0-4 213.00 ( 0.00%) 213.00 ( 0.00%) Min alloc-odr0-8 186.00 ( 0.00%) 183.00 ( 1.61%) Min alloc-odr0-16 173.00 ( 0.00%) 171.00 ( 1.16%) Min alloc-odr0-32 166.00 ( 0.00%) 163.00 ( 1.81%) Min alloc-odr0-64 162.00 ( 0.00%) 159.00 ( 1.85%) Min alloc-odr0-128 160.00 ( 0.00%) 157.00 ( 1.88%) Min alloc-odr0-256 169.00 ( 0.00%) 166.00 ( 1.78%) Min alloc-odr0-512 180.00 ( 0.00%) 180.00 ( 0.00%) Min alloc-odr0-1024 188.00 ( 0.00%) 187.00 ( 0.53%) Min alloc-odr0-2048 194.00 ( 0.00%) 193.00 ( 0.52%) Min alloc-odr0-4096 199.00 ( 0.00%) 198.00 ( 0.50%) Min alloc-odr0-8192 202.00 ( 0.00%) 201.00 ( 0.50%) Min alloc-odr0-16384 203.00 ( 0.00%) 202.00 ( 0.49%) Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Zefan Li <lizefan@huawei.com> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cpuset.c14
1 files changed, 7 insertions, 7 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 611cc69af8f0..73e93e53884d 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -61,7 +61,7 @@
#include <linux/cgroup.h>
#include <linux/wait.h>
-struct static_key cpusets_enabled_key __read_mostly = STATIC_KEY_INIT_FALSE;
+DEFINE_STATIC_KEY_FALSE(cpusets_enabled_key);
/* See "Frequency meter" comments, below. */
@@ -2528,27 +2528,27 @@ static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs)
* GFP_KERNEL - any node in enclosing hardwalled cpuset ok
* GFP_USER - only nodes in current tasks mems allowed ok.
*/
-int __cpuset_node_allowed(int node, gfp_t gfp_mask)
+bool __cpuset_node_allowed(int node, gfp_t gfp_mask)
{
struct cpuset *cs; /* current cpuset ancestors */
int allowed; /* is allocation in zone z allowed? */
unsigned long flags;
if (in_interrupt())
- return 1;
+ return true;
if (node_isset(node, current->mems_allowed))
- return 1;
+ return true;
/*
* Allow tasks that have access to memory reserves because they have
* been OOM killed to get memory anywhere.
*/
if (unlikely(test_thread_flag(TIF_MEMDIE)))
- return 1;
+ return true;
if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */
- return 0;
+ return false;
if (current->flags & PF_EXITING) /* Let dying task have memory */
- return 1;
+ return true;
/* Not hardwall and node outside mems_allowed: scan up cpusets */
spin_lock_irqsave(&callback_lock, flags);