From 4c3ccec06be99c533525edaf92a50f3d7794c15e Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 31 Oct 2012 13:56:08 +0100 Subject: [PATCH] sched, numa, mm: Count WS scanning against present PTEs, not virtual memory ranges By accounting against the present PTEs, scanning speed reflects the actual present (mapped) memory. Suggested-by: Ingo Molnar Signed-off-by: Peter Zijlstra Cc: Linus Torvalds Cc: Andrew Morton Cc: Andrea Arcangeli Cc: Rik van Riel Cc: Mel Gorman Cc: Hugh Dickins Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 37 +++++++++++++++++++++---------------- 1 file changed, 21 insertions(+), 16 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 151a3cda6475..da28315777b7 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -914,8 +914,8 @@ void task_numa_work(struct callback_head *work) struct task_struct *p = current; struct mm_struct *mm = p->mm; struct vm_area_struct *vma; - unsigned long offset, end; - long length; + unsigned long start, end; + long pages; WARN_ON_ONCE(p != container_of(work, struct task_struct, numa_work)); @@ -942,30 +942,35 @@ void task_numa_work(struct callback_head *work) if (cmpxchg(&mm->numa_next_scan, migrate, next_scan) != migrate) return; - offset = mm->numa_scan_offset; - length = sysctl_sched_numa_scan_size; - length <<= 20; + start = mm->numa_scan_offset; + pages = sysctl_sched_numa_scan_size; + pages <<= 20 - PAGE_SHIFT; /* MB in pages */ + if (!pages) + return; down_write(&mm->mmap_sem); - vma = find_vma(mm, offset); + vma = find_vma(mm, start); if (!vma) { ACCESS_ONCE(mm->numa_scan_seq)++; - offset = 0; + start = 0; vma = mm->mmap; } - for (; vma && length > 0; vma = vma->vm_next) { + for (; vma; vma = vma->vm_next) { if (!vma_migratable(vma)) continue; - offset = max(offset, vma->vm_start); - end = min(ALIGN(offset + length, HPAGE_SIZE), vma->vm_end); - length -= end - offset; - - change_prot_numa(vma, offset, end); - - offset = end; + do { + start = max(start, vma->vm_start); + end = ALIGN(start + (pages << PAGE_SHIFT), HPAGE_SIZE); + end = min(end, vma->vm_end); + pages -= change_prot_numa(vma, start, end); + start = end; + if (pages <= 0) + goto out; + } while (end != vma->vm_end); } - mm->numa_scan_offset = offset; +out: + mm->numa_scan_offset = start; up_write(&mm->mmap_sem); } -- 2.39.5