The patch titled
Subject: mm/ksm: add pages scanned metric
has been added to the -mm mm-unstable branch. Its filename is
mm-ksm-add-pages-scanned-metric.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-ksm-add-pages-scanned-metric.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
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branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Stefan Roesch <shr@xxxxxxxxxxxx>
Subject: mm/ksm: add pages scanned metric
Date: Fri, 11 Aug 2023 12:36:55 -0700
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@xxxxxxxxxxxx
Signed-off-by: Stefan Roesch <shr@xxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/mm/ksm.rst | 2 ++
mm/ksm.c | 16 +++++++++++++++-
2 files changed, 17 insertions(+), 1 deletion(-)
--- a/Documentation/admin-guide/mm/ksm.rst~mm-ksm-add-pages-scanned-metric
+++ a/Documentation/admin-guide/mm/ksm.rst
@@ -159,6 +159,8 @@ The effectiveness of KSM and MADV_MERGEA
general_profit
how effective is KSM. The calculation is explained below.
+pages_scanned
+ how many pages are being scanned for ksm
pages_shared
how many shared pages are being used
pages_sharing
--- a/mm/ksm.c~mm-ksm-add-pages-scanned-metric
+++ a/mm/ksm.c
@@ -242,6 +242,9 @@ static struct kmem_cache *rmap_item_cach
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;
@@ -2483,8 +2486,9 @@ static void ksm_do_scan(unsigned int sca
{
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)
@@ -2492,6 +2496,8 @@ static void ksm_do_scan(unsigned int sca
cmp_and_merge_page(page, rmap_item);
put_page(page);
}
+
+ ksm_pages_scanned += scan_npages - npages;
}
static int ksmd_should_run(void)
@@ -3332,6 +3338,13 @@ static ssize_t max_page_sharing_store(st
}
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)
{
@@ -3440,6 +3453,7 @@ 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,
_
Patches currently in -mm which might be from shr@xxxxxxxxxxxx are
proc-ksm-add-ksm-stats-to-proc-pid-smaps.patch
mm-ksm-add-pages-scanned-metric.patch
