diff mbox series

[055/156] mm/page_poison.c: replace bool variable with static key

Message ID 20201016024420.9hwA7Xra2%akpm@linux-foundation.org
State New
Headers show
Series [001/156] device-dax/kmem: fix resource release | expand

Commit Message

Andrew Morton Oct. 16, 2020, 2:44 a.m. UTC
From: Mateusz Nosek <mateusznosek0@gmail.com>
Subject: mm/page_poison.c: replace bool variable with static key

Variable 'want_page_poisoning' is a switch deciding if page poisoning
should be enabled.  This patch changes it to be static key.

Link: https://lkml.kernel.org/r/20200921152931.938-1-mateusznosek0@gmail.com
Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Oscar Salvador <OSalvador@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_poison.c |   20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)
diff mbox series

Patch

--- a/mm/page_poison.c~mm-page_poisonc-replace-bool-variable-with-static-key
+++ a/mm/page_poison.c
@@ -8,13 +8,23 @@ 
 #include <linux/ratelimit.h>
 #include <linux/kasan.h>
 
-static bool want_page_poisoning __read_mostly;
+static DEFINE_STATIC_KEY_FALSE_RO(want_page_poisoning);
 
 static int __init early_page_poison_param(char *buf)
 {
-	if (!buf)
-		return -EINVAL;
-	return strtobool(buf, &want_page_poisoning);
+	int ret;
+	bool tmp;
+
+	ret = strtobool(buf, &tmp);
+	if (ret)
+		return ret;
+
+	if (tmp)
+		static_branch_enable(&want_page_poisoning);
+	else
+		static_branch_disable(&want_page_poisoning);
+
+	return 0;
 }
 early_param("page_poison", early_page_poison_param);
 
@@ -31,7 +41,7 @@  bool page_poisoning_enabled(void)
 	 * Page poisoning is debug page alloc for some arches. If
 	 * either of those options are enabled, enable poisoning.
 	 */
-	return (want_page_poisoning ||
+	return (static_branch_unlikely(&want_page_poisoning) ||
 		(!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) &&
 		debug_pagealloc_enabled()));
 }