2013-09-05 08:08:42

by Jianguo Wu

Subject: [PATCH v2][RESEND] mm/thp: fix stale comments of transparent_hugepage_flags

Changelog:
*v1 -> v2: also update the stale comments about default transparent
hugepage support pointed by Wanpeng Li.

Since commit 13ece886d9(thp: transparent hugepage config choice),
transparent hugepage support is disabled by default, and
TRANSPARENT_HUGEPAGE_ALWAYS is configured when TRANSPARENT_HUGEPAGE=y.

And since commit d39d33c332(thp: enable direct defrag), defrag is
enable for all transparent hugepage page faults by default, not only in
MADV_HUGEPAGE regions.

Signed-off-by: Jianguo Wu <[email protected]>
---
mm/huge_memory.c | 11 ++++++-----
1 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index a92012a..90ce6de 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -27,11 +27,12 @@
#include "internal.h"

/*
- * By default transparent hugepage support is enabled for all mappings
- * and khugepaged scans all mappings. Defrag is only invoked by
- * khugepaged hugepage allocations and by page faults inside
- * MADV_HUGEPAGE regions to avoid the risk of slowing down short lived
- * allocations.
+ * By default transparent hugepage support is disabled in order that avoid
+ * to risk increase the memory footprint of applications without a guaranteed
+ * benefit. When transparent hugepage support is enabled, is for all mappings,
+ * and khugepaged scans all mappings.
+ * Defrag is invoked by khugepaged hugepage allocations and by page faults
+ * for all hugepage allocations.
*/
unsigned long transparent_hugepage_flags __read_mostly =
#ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS
--
1.7.1

2013-09-05 11:25:31

by Kirill A. Shutemov

Subject: RE: [PATCH v2][RESEND] mm/thp: fix stale comments of transparent_hugepage_flags

Jianguo Wu wrote:
> Changelog:
> *v1 -> v2: also update the stale comments about default transparent
> hugepage support pointed by Wanpeng Li.
>
> Since commit 13ece886d9(thp: transparent hugepage config choice),
> transparent hugepage support is disabled by default, and
> TRANSPARENT_HUGEPAGE_ALWAYS is configured when TRANSPARENT_HUGEPAGE=y.
>
> And since commit d39d33c332(thp: enable direct defrag), defrag is
> enable for all transparent hugepage page faults by default, not only in
> MADV_HUGEPAGE regions.
>
> Signed-off-by: Jianguo Wu <[email protected]>

Acked-by: Kirill A. Shutemov <[email protected]>

--
Kirill A. Shutemov