linux-kernel - [PATCH 1/3] mm: completely disable THP by transparent

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Date:	Tue, 21 Jun 2011 00:34:28 +0800
From:	Amerigo Wang <amwang@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	akpm@...ux-foundation.org, Amerigo Wang <amwang@...hat.com>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Rik van Riel <riel@...hat.com>,
	Johannes Weiner <jweiner@...hat.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	linux-mm@...ck.org
Subject: [PATCH 1/3] mm: completely disable THP by transparent_hugepage=never

transparent_hugepage=never should mean to disable THP completely,
otherwise we don't have a way to disable THP completely.
The design is broken.

Signed-off-by: WANG Cong <amwang@...hat.com>
---
 mm/huge_memory.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 81532f2..9c63c90 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -488,19 +488,26 @@ static struct attribute_group khugepaged_attr_group = {
 };
 #endif /* CONFIG_SYSFS */
 
+#define hugepage_enabled()	khugepaged_enabled()
+
 static int __init hugepage_init(void)
 {
-	int err;
+	int err = 0;
 #ifdef CONFIG_SYSFS
 	static struct kobject *hugepage_kobj;
 #endif
 
-	err = -EINVAL;
 	if (!has_transparent_hugepage()) {
+		err = -EINVAL;
 		transparent_hugepage_flags = 0;
 		goto out;
 	}
 
+	if (!hugepage_enabled()) {
+		printk(KERN_INFO "hugepage: totally disabled\n");
+		goto out;
+	}
+
 #ifdef CONFIG_SYSFS
 	err = -ENOMEM;
 	hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj);
-- 
1.7.4.4

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