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| author | Andrea Arcangeli <aarcange@redhat.com> | 2011-01-13 15:47:07 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-13 17:32:45 -0800 |
| commit | 13ece886d99cd668483113f7238e419d5331af26 (patch) | |
| tree | 44a1c65870ba4463316f943f52d898bb3763ab81 | |
| parent | ce83d2174ea9c3d72d5821cf3ebc974e36391bf7 (diff) | |
| download | op-kernel-dev-13ece886d99cd668483113f7238e419d5331af26.zip op-kernel-dev-13ece886d99cd668483113f7238e419d5331af26.tar.gz | |
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>
| -rw-r--r-- | mm/Kconfig | 27 | ||||
| -rw-r--r-- | mm/huge_memory.c | 5 |
2 files changed, 30 insertions, 2 deletions
@@ -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 bce6e12..30c3cec 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); |
