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authorVlastimil Babka <vbabka@suse.cz>2016-03-15 14:56:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-15 16:55:16 -0700
commit7dd80b8af0bcd705a9ef2fa272c082882616a499 (patch)
tree75048a0e7ff2648c59b1a23640e202653fa1aa27 /mm/page_owner.c
parent60f30350fd69a3e4d5f0f45937d3274c22565134 (diff)
downloadlinux-7dd80b8af0bcd705a9ef2fa272c082882616a499.tar.gz
mm, page_owner: convert page_owner_inited to static key
CONFIG_PAGE_OWNER attempts to impose negligible runtime overhead when enabled during compilation, but not actually enabled during runtime by boot param page_owner=on. This overhead can be further reduced using the static key mechanism, which this patch does. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_owner.c')
-rw-r--r--mm/page_owner.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/mm/page_owner.c b/mm/page_owner.c
index 7a37a30d941b..feaa28b40c1c 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -5,10 +5,11 @@
#include <linux/bootmem.h>
#include <linux/stacktrace.h>
#include <linux/page_owner.h>
+#include <linux/jump_label.h>
#include "internal.h"
static bool page_owner_disabled = true;
-bool page_owner_inited __read_mostly;
+DEFINE_STATIC_KEY_FALSE(page_owner_inited);
static void init_early_allocated_pages(void);
@@ -37,7 +38,7 @@ static void init_page_owner(void)
if (page_owner_disabled)
return;
- page_owner_inited = true;
+ static_branch_enable(&page_owner_inited);
init_early_allocated_pages();
}
@@ -147,7 +148,7 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
struct page *page;
struct page_ext *page_ext;
- if (!page_owner_inited)
+ if (!static_branch_unlikely(&page_owner_inited))
return -EINVAL;
page = NULL;
@@ -295,7 +296,7 @@ static int __init pageowner_init(void)
{
struct dentry *dentry;
- if (!page_owner_inited) {
+ if (!static_branch_unlikely(&page_owner_inited)) {
pr_info("page_owner is disabled\n");
return 0;
}