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authorStefan Roesch <shr@devkernel.io>2023-08-11 12:36:55 -0700
committerAndrew Morton <akpm@linux-foundation.org>2023-08-21 13:38:02 -0700
commitb348b5fe2b5f14ac8bb64fe271d7a027db8cc674 (patch)
treecf5763397ef785757026521d9014225da3b483a8 /mm
parent0790e1e2b1b71ba357e89e779451efe79dff28e6 (diff)
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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 <shr@devkernel.io> Acked-by: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/ksm.c16
1 files changed, 15 insertions, 1 deletions
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,