From: Vijay Balakrishna <[email protected]> commit 4aab2be0983031a05cb4a19696c9da5749523426 upstream.
When memory is hotplug added or removed the min_free_kbytes should be recalculated based on what is expected by khugepaged. Currently after hotplug, min_free_kbytes will be set to a lower default and higher default set when THP enabled is lost. This change restores min_free_kbytes as expected for THP consumers. [[email protected]: v5] Link: https://lkml.kernel.org/r/[email protected] Fixes: f000565adb77 ("thp: set recommended min free kbytes") Signed-off-by: Vijay Balakrishna <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Reviewed-by: Pavel Tatashin <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Allen Pais <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: "Kirill A. Shutemov" <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Song Liu <[email protected]> Cc: <[email protected]> Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- include/linux/khugepaged.h | 5 +++++ mm/khugepaged.c | 13 +++++++++++-- mm/page_alloc.c | 3 +++ 3 files changed, 19 insertions(+), 2 deletions(-) --- a/include/linux/khugepaged.h +++ b/include/linux/khugepaged.h @@ -15,6 +15,7 @@ extern int __khugepaged_enter(struct mm_ extern void __khugepaged_exit(struct mm_struct *mm); extern int khugepaged_enter_vma_merge(struct vm_area_struct *vma, unsigned long vm_flags); +extern void khugepaged_min_free_kbytes_update(void); #define khugepaged_enabled() \ (transparent_hugepage_flags & \ @@ -73,6 +74,10 @@ static inline int khugepaged_enter_vma_m { return 0; } + +static inline void khugepaged_min_free_kbytes_update(void) +{ +} #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ #endif /* _LINUX_KHUGEPAGED_H */ --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -53,6 +53,9 @@ enum scan_result { #define CREATE_TRACE_POINTS #include <trace/events/huge_memory.h> +static struct task_struct *khugepaged_thread __read_mostly; +static DEFINE_MUTEX(khugepaged_mutex); + /* default scan 8*512 pte (or vmas) every 30 second */ static unsigned int khugepaged_pages_to_scan __read_mostly; static unsigned int khugepaged_pages_collapsed; @@ -1952,8 +1955,6 @@ static void set_recommended_min_free_kby int start_stop_khugepaged(void) { - static struct task_struct *khugepaged_thread __read_mostly; - static DEFINE_MUTEX(khugepaged_mutex); int err = 0; mutex_lock(&khugepaged_mutex); @@ -1980,3 +1981,11 @@ fail: mutex_unlock(&khugepaged_mutex); return err; } + +void khugepaged_min_free_kbytes_update(void) +{ + mutex_lock(&khugepaged_mutex); + if (khugepaged_enabled() && khugepaged_thread) + set_recommended_min_free_kbytes(); + mutex_unlock(&khugepaged_mutex); +} --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -66,6 +66,7 @@ #include <linux/ftrace.h> #include <linux/lockdep.h> #include <linux/nmi.h> +#include <linux/khugepaged.h> #include <asm/sections.h> #include <asm/tlbflush.h> @@ -7399,6 +7400,8 @@ int __meminit init_per_zone_wmark_min(vo setup_min_slab_ratio(); #endif + khugepaged_min_free_kbytes_update(); + return 0; } postcore_initcall(init_per_zone_wmark_min)
