| Message ID | 20230811193655.2518943-1-shr@devkernel.io (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v1] mm/ksm: add pages scanned metric | expand |
On 11.08.23 21:36, Stefan Roesch wrote: > 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. > > Signed-off-by: Stefan Roesch <shr@devkernel.io> > --- > Documentation/admin-guide/mm/ksm.rst | 2 ++ > mm/ksm.c | 16 +++++++++++++++- > 2 files changed, 17 insertions(+), 1 deletion(-) > > diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst > index 5c5be7bd84b8..776f244bdae4 100644 > --- a/Documentation/admin-guide/mm/ksm.rst > +++ b/Documentation/admin-guide/mm/ksm.rst > @@ -159,6 +159,8 @@ The effectiveness of KSM and MADV_MERGEABLE is shown in ``/sys/kernel/mm/ksm/``: > > 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 > diff --git a/mm/ksm.c b/mm/ksm.c > index 6b7b8928fb96..8d6aee05421d 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; > + LGTM Acked-by: David Hildenbrand <david@redhat.com>
diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst index 5c5be7bd84b8..776f244bdae4 100644 --- a/Documentation/admin-guide/mm/ksm.rst +++ b/Documentation/admin-guide/mm/ksm.rst @@ -159,6 +159,8 @@ The effectiveness of KSM and MADV_MERGEABLE is shown in ``/sys/kernel/mm/ksm/``: 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 diff --git a/mm/ksm.c b/mm/ksm.c index 6b7b8928fb96..8d6aee05421d 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; @@ -2483,8 +2486,9 @@ 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) @@ -2492,6 +2496,8 @@ 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) @@ -3332,6 +3338,13 @@ 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) { @@ -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,
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. Signed-off-by: Stefan Roesch <shr@devkernel.io> --- Documentation/admin-guide/mm/ksm.rst | 2 ++ mm/ksm.c | 16 +++++++++++++++- 2 files changed, 17 insertions(+), 1 deletion(-) base-commit: f4a280e5bb4a764a75d3215b61bc0f02b4c26417