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authorAndrea Arcangeli <aarcange@redhat.com>2011-01-13 15:47:07 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-13 17:32:45 -0800
commit13ece886d99cd668483113f7238e419d5331af26 (patch)
tree44a1c65870ba4463316f943f52d898bb3763ab81 /mm
parentce83d2174ea9c3d72d5821cf3ebc974e36391bf7 (diff)
thp: transparent hugepage config choice
Allow to choose between the always|madvise default for page faults and khugepaged at config time. madvise guarantees zero risk of higher memory footprint for applications (applications using madvise(MADV_HUGEPAGE) won't risk to use any more memory by backing their virtual regions with hugepages). Initially set the default to N and don't depend on EMBEDDED. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/Kconfig27
-rw-r--r--mm/huge_memory.c5
2 files changed, 30 insertions, 2 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index d774f77538ce..3e81687263b5 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -303,9 +303,8 @@ config NOMMU_INITIAL_TRIM_EXCESS
See Documentation/nommu-mmap.txt for more information.
config TRANSPARENT_HUGEPAGE
- bool "Transparent Hugepage Support" if EMBEDDED
+ bool "Transparent Hugepage Support"
depends on X86 && MMU
- default y
help
Transparent Hugepages allows the kernel to use huge pages and
huge tlb transparently to the applications whenever possible.
@@ -316,6 +315,30 @@ config TRANSPARENT_HUGEPAGE
If memory constrained on embedded, you may want to say N.
+choice
+ prompt "Transparent Hugepage Support sysfs defaults"
+ depends on TRANSPARENT_HUGEPAGE
+ default TRANSPARENT_HUGEPAGE_ALWAYS
+ help
+ Selects the sysfs defaults for Transparent Hugepage Support.
+
+ config TRANSPARENT_HUGEPAGE_ALWAYS
+ bool "always"
+ help
+ Enabling Transparent Hugepage always, can increase the
+ memory footprint of applications without a guaranteed
+ benefit but it will work automatically for all applications.
+
+ config TRANSPARENT_HUGEPAGE_MADVISE
+ bool "madvise"
+ help
+ Enabling Transparent Hugepage madvise, will only provide a
+ performance improvement benefit to the applications using
+ madvise(MADV_HUGEPAGE) but it won't risk to increase the
+ memory footprint of applications without a guaranteed
+ benefit.
+endchoice
+
#
# UP and nommu archs use km based percpu allocator
#
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index bce6e12140e2..30c3cec82023 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -27,7 +27,12 @@
* allocations.
*/
unsigned long transparent_hugepage_flags __read_mostly =
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS
(1<<TRANSPARENT_HUGEPAGE_FLAG)|
+#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE
+ (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)|
+#endif
(1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)|
(1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG);