This patch takes back allocstall comparing when deciding whether swapin worthwhile because it does not work, if vmevent disabled.
Related commit: http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=2548306628308aa6a326640d345a737bc898941d Signed-off-by: Ebru Akagunduz <ebru.akagun...@gmail.com> Suggested-by: Minchan Kim <minc...@kernel.org> Suggested-by: Michal Hocko <mho...@kernel.org> --- Changes in v2: - Add Suggested-by tag (Minchan Kim) mm/huge_memory.c | 30 ++++++++---------------------- 1 file changed, 8 insertions(+), 22 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index acd374e..34fec1f 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -102,7 +102,6 @@ static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait); */ static unsigned int khugepaged_max_ptes_none __read_mostly; static unsigned int khugepaged_max_ptes_swap __read_mostly; -static unsigned long allocstall; static int khugepaged(void *none); static int khugepaged_slab_init(void); @@ -2465,7 +2464,6 @@ static void collapse_huge_page(struct mm_struct *mm, struct page *new_page; spinlock_t *pmd_ptl, *pte_ptl; int isolated = 0, result = 0; - unsigned long swap, curr_allocstall; struct mem_cgroup *memcg; unsigned long mmun_start; /* For mmu_notifiers */ unsigned long mmun_end; /* For mmu_notifiers */ @@ -2488,8 +2486,6 @@ static void collapse_huge_page(struct mm_struct *mm, goto out_nolock; } - swap = get_mm_counter(mm, MM_SWAPENTS); - curr_allocstall = sum_vm_event(ALLOCSTALL); down_read(&mm->mmap_sem); result = hugepage_vma_revalidate(mm, address); if (result) { @@ -2507,20 +2503,14 @@ static void collapse_huge_page(struct mm_struct *mm, } /* - * Don't perform swapin readahead when the system is under pressure, - * to avoid unnecessary resource consumption. + * __collapse_huge_page_swapin always returns with mmap_sem + * locked. If it fails, release mmap_sem and jump directly + * out. Continuing to collapse causes inconsistency. */ - if (allocstall == curr_allocstall && swap != 0) { - /* - * __collapse_huge_page_swapin always returns with mmap_sem - * locked. If it fails, release mmap_sem and jump directly - * out. Continuing to collapse causes inconsistency. - */ - if (!__collapse_huge_page_swapin(mm, vma, address, pmd)) { - mem_cgroup_cancel_charge(new_page, memcg, true); - up_read(&mm->mmap_sem); - goto out_nolock; - } + if (!__collapse_huge_page_swapin(mm, vma, address, pmd)) { + mem_cgroup_cancel_charge(new_page, memcg, true); + up_read(&mm->mmap_sem); + goto out_nolock; } up_read(&mm->mmap_sem); @@ -2935,7 +2925,6 @@ static void khugepaged_wait_work(void) if (!scan_sleep_jiffies) return; - allocstall = sum_vm_event(ALLOCSTALL); khugepaged_sleep_expire = jiffies + scan_sleep_jiffies; wait_event_freezable_timeout(khugepaged_wait, khugepaged_should_wakeup(), @@ -2943,10 +2932,8 @@ static void khugepaged_wait_work(void) return; } - if (khugepaged_enabled()) { - allocstall = sum_vm_event(ALLOCSTALL); + if (khugepaged_enabled()) wait_event_freezable(khugepaged_wait, khugepaged_wait_event()); - } } static int khugepaged(void *none) @@ -2955,7 +2942,6 @@ static int khugepaged(void *none) set_freezable(); set_user_nice(current, MAX_NICE); - allocstall = sum_vm_event(ALLOCSTALL); while (!kthread_should_stop()) { khugepaged_do_scan(); -- 1.9.1
