From 13ece886d99cd668483113f7238e419d5331af26 Mon Sep 17 00:00:00 2001 From: Andrea Arcangeli Date: Thu, 13 Jan 2011 15:47:07 -0800 Subject: [PATCH] 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/Kconfig | 27 +++++++++++++++++++++++++-- mm/huge_memory.c | 5 +++++ 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<