From b348b5fe2b5f14ac8bb64fe271d7a027db8cc674 Mon Sep 17 00:00:00 2001 From: Stefan Roesch Date: Fri, 11 Aug 2023 12:36:55 -0700 Subject: mm/ksm: add pages scanned metric ksm currently maintains several statistics, which let you determine how successful KSM is at sharing pages. However it does not contain a metric to determine how much work it does. This commit adds the pages scanned metric. This allows the administrator to determine how many pages have been scanned over a period of time. Link: https://lkml.kernel.org/r/20230811193655.2518943-1-shr@devkernel.io Signed-off-by: Stefan Roesch Acked-by: David Hildenbrand Cc: Johannes Weiner Cc: Rik van Riel Signed-off-by: Andrew Morton --- mm/ksm.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'mm/ksm.c') diff --git a/mm/ksm.c b/mm/ksm.c index 97a9627116fa..2653099539f2 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -242,6 +242,9 @@ static struct kmem_cache *rmap_item_cache; static struct kmem_cache *stable_node_cache; static struct kmem_cache *mm_slot_cache; +/* The number of pages scanned */ +static unsigned long ksm_pages_scanned; + /* The number of nodes in the stable tree */ static unsigned long ksm_pages_shared; @@ -2476,8 +2479,9 @@ static void ksm_do_scan(unsigned int scan_npages) { struct ksm_rmap_item *rmap_item; struct page *page; + unsigned int npages = scan_npages; - while (scan_npages-- && likely(!freezing(current))) { + while (npages-- && likely(!freezing(current))) { cond_resched(); rmap_item = scan_get_next_rmap_item(&page); if (!rmap_item) @@ -2485,6 +2489,8 @@ static void ksm_do_scan(unsigned int scan_npages) cmp_and_merge_page(page, rmap_item); put_page(page); } + + ksm_pages_scanned += scan_npages - npages; } static int ksmd_should_run(void) @@ -3323,6 +3329,13 @@ static ssize_t max_page_sharing_store(struct kobject *kobj, } KSM_ATTR(max_page_sharing); +static ssize_t pages_scanned_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%lu\n", ksm_pages_scanned); +} +KSM_ATTR_RO(pages_scanned); + static ssize_t pages_shared_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { @@ -3431,6 +3444,7 @@ static struct attribute *ksm_attrs[] = { &sleep_millisecs_attr.attr, &pages_to_scan_attr.attr, &run_attr.attr, + &pages_scanned_attr.attr, &pages_shared_attr.attr, &pages_sharing_attr.attr, &pages_unshared_attr.attr, -- cgit v1.2.3