This part of the patch adds a tunable to /sys/kernel/mm/transparent_hugepage called threshold. This threshold determines how many pages a user must fault in from a single node before a temporary compound page is turned into a THP.
Signed-off-by: Alex Thorlton <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Nate Zimmer <[email protected]> Cc: Cliff Wickman <[email protected]> Cc: "Kirill A. Shutemov" <[email protected]> Cc: Benjamin Herrenschmidt <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Wanpeng Li <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Michel Lespinasse <[email protected]> Cc: Benjamin LaHaise <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: "Eric W. Biederman" <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Al Viro <[email protected]> Cc: David Rientjes <[email protected]> Cc: Zhang Yanfei <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Johannes Weiner <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Jiang Liu <[email protected]> Cc: Cody P Schafer <[email protected]> Cc: Glauber Costa <[email protected]> Cc: Kamezawa Hiroyuki <[email protected]> Cc: David Rientjes <[email protected]> Cc: Naoya Horiguchi <[email protected]> Cc: [email protected] Cc: [email protected] --- include/linux/huge_mm.h | 2 ++ include/linux/mm_types.h | 1 + mm/huge_memory.c | 30 ++++++++++++++++++++++++++++++ 3 files changed, 33 insertions(+) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 3935428..0943b1b6 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -177,6 +177,8 @@ static inline struct page *compound_trans_head(struct page *page) extern int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, pmd_t pmd, pmd_t *pmdp); +extern int thp_threshold_check(void); + #else /* CONFIG_TRANSPARENT_HUGEPAGE */ #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; }) #define HPAGE_PMD_MASK ({ BUILD_BUG(); 0; }) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index d9851ee..b5efa23 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -408,6 +408,7 @@ struct mm_struct { #endif #ifdef CONFIG_TRANSPARENT_HUGEPAGE pgtable_t pmd_huge_pte; /* protected by page_table_lock */ + int thp_threshold; #endif #ifdef CONFIG_CPUMASK_OFFSTACK struct cpumask cpumask_allocation; diff --git a/mm/huge_memory.c b/mm/huge_memory.c index cca80d9..5d388e4 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -44,6 +44,9 @@ unsigned long transparent_hugepage_flags __read_mostly = (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); +/* default to 1 page threshold for handing out thps; maintains old behavior */ +static int transparent_hugepage_threshold = 1; + /* default scan 8*512 pte (or vmas) every 30 second */ static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8; static unsigned int khugepaged_pages_collapsed; @@ -237,6 +240,11 @@ static struct shrinker huge_zero_page_shrinker = { .seeks = DEFAULT_SEEKS, }; +int thp_threshold_check() +{ + return transparent_hugepage_threshold; +} + #ifdef CONFIG_SYSFS static ssize_t double_flag_show(struct kobject *kobj, @@ -376,6 +384,27 @@ static ssize_t use_zero_page_store(struct kobject *kobj, } static struct kobj_attribute use_zero_page_attr = __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); +static ssize_t threshold_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", transparent_hugepage_threshold); +} +static ssize_t threshold_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int err, value; + + err = kstrtoint(buf, 10, &value); + if (err || value < 1 || value > HPAGE_PMD_NR) + return -EINVAL; + + transparent_hugepage_threshold = value; + + return count; +} +static struct kobj_attribute threshold_attr = + __ATTR(threshold, 0644, threshold_show, threshold_store); #ifdef CONFIG_DEBUG_VM static ssize_t debug_cow_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) @@ -397,6 +426,7 @@ static struct kobj_attribute debug_cow_attr = static struct attribute *hugepage_attr[] = { &enabled_attr.attr, &defrag_attr.attr, + &threshold_attr.attr, &use_zero_page_attr.attr, #ifdef CONFIG_DEBUG_VM &debug_cow_attr.attr, -- 1.7.12.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
