From: Andrea Arcangeli <aarcange@xxxxxxxxxx> 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@xxxxxxxxxx> --- diff --git a/mm/Kconfig b/mm/Kconfig --- 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 --- 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); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>