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Diffstat (limited to 'mm/ksm.c')
-rw-r--r--mm/ksm.c44
1 files changed, 38 insertions, 6 deletions
diff --git a/mm/ksm.c b/mm/ksm.c
index d7b5b95e936e..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;
@@ -278,6 +281,9 @@ static unsigned int zero_checksum __read_mostly;
/* Whether to merge empty (zeroed) pages with actual zero pages */
static bool ksm_use_zero_pages __read_mostly;
+/* The number of zero pages which is placed by KSM */
+unsigned long ksm_zero_pages;
+
#ifdef CONFIG_NUMA
/* Zeroed when merging across nodes is not allowed */
static unsigned int ksm_merge_across_nodes = 1;
@@ -448,7 +454,8 @@ static int break_ksm_pmd_entry(pmd_t *pmd, unsigned long addr, unsigned long nex
if (is_migration_entry(entry))
page = pfn_swap_entry_to_page(entry);
}
- ret = page && PageKsm(page);
+ /* return 1 if the page is an normal ksm page or KSM-placed zero page */
+ ret = (page && PageKsm(page)) || is_ksm_zero_pte(*pte);
pte_unmap_unlock(pte, ptl);
return ret;
}
@@ -1229,8 +1236,14 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
page_add_anon_rmap(kpage, vma, addr, RMAP_NONE);
newpte = mk_pte(kpage, vma->vm_page_prot);
} else {
- newpte = pte_mkspecial(pfn_pte(page_to_pfn(kpage),
- vma->vm_page_prot));
+ /*
+ * Use pte_mkdirty to mark the zero page mapped by KSM, and then
+ * we can easily track all KSM-placed zero pages by checking if
+ * the dirty bit in zero page's PTE is set.
+ */
+ newpte = pte_mkdirty(pte_mkspecial(pfn_pte(page_to_pfn(kpage), vma->vm_page_prot)));
+ ksm_zero_pages++;
+ mm->ksm_zero_pages++;
/*
* We're replacing an anonymous page with a zero page, which is
* not anonymous. We need to do proper accounting otherwise we
@@ -2473,8 +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)
@@ -2482,6 +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)
@@ -3091,7 +3107,7 @@ static void wait_while_offlining(void)
#ifdef CONFIG_PROC_FS
long ksm_process_profit(struct mm_struct *mm)
{
- return mm->ksm_merging_pages * PAGE_SIZE -
+ return (long)(mm->ksm_merging_pages + mm->ksm_zero_pages) * PAGE_SIZE -
mm->ksm_rmap_items * sizeof(struct ksm_rmap_item);
}
#endif /* CONFIG_PROC_FS */
@@ -3322,6 +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)
{
@@ -3360,12 +3383,19 @@ static ssize_t pages_volatile_show(struct kobject *kobj,
}
KSM_ATTR_RO(pages_volatile);
+static ssize_t ksm_zero_pages_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ return sysfs_emit(buf, "%ld\n", ksm_zero_pages);
+}
+KSM_ATTR_RO(ksm_zero_pages);
+
static ssize_t general_profit_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
long general_profit;
- general_profit = ksm_pages_sharing * PAGE_SIZE -
+ general_profit = (ksm_pages_sharing + ksm_zero_pages) * PAGE_SIZE -
ksm_rmap_items * sizeof(struct ksm_rmap_item);
return sysfs_emit(buf, "%ld\n", general_profit);
@@ -3423,10 +3453,12 @@ 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,
&pages_volatile_attr.attr,
+ &ksm_zero_pages_attr.attr,
&full_scans_attr.attr,
#ifdef CONFIG_NUMA
&merge_across_nodes_attr.attr,