vmstat: mlocked pages statistics
Add NR_MLOCK zone page state, which provides a (conservative) count of
mlocked pages (actually, the number of mlocked pages moved off the LRU).
Reworked by lts to fit in with the modified mlock page support in the
Reclaim Scalability series.
[kosaki.motohiro@jp.fujitsu.com: fix incorrect Mlocked field of /proc/meminfo]
[lee.schermerhorn@hp.com: mlocked-pages: add event counting with statistics]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/base/node.c b/drivers/base/node.c
index 11a9a05..fb45d88 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -71,7 +71,8 @@
"Node %d Active(file): %8lu kB\n"
"Node %d Inactive(file): %8lu kB\n"
#ifdef CONFIG_UNEVICTABLE_LRU
- "Node %d Noreclaim: %8lu kB\n"
+ "Node %d Unevictable: %8lu kB\n"
+ "Node %d Mlocked: %8lu kB\n"
#endif
#ifdef CONFIG_HIGHMEM
"Node %d HighTotal: %8lu kB\n"
@@ -104,6 +105,7 @@
nid, K(node_page_state(nid, NR_INACTIVE_FILE)),
#ifdef CONFIG_UNEVICTABLE_LRU
nid, K(node_page_state(nid, NR_UNEVICTABLE)),
+ nid, K(node_page_state(nid, NR_MLOCK)),
#endif
#ifdef CONFIG_HIGHMEM
nid, K(i.totalhigh),
diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c
index 6dd60ea..61b25f4 100644
--- a/fs/proc/proc_misc.c
+++ b/fs/proc/proc_misc.c
@@ -176,6 +176,7 @@
"Inactive(file): %8lu kB\n"
#ifdef CONFIG_UNEVICTABLE_LRU
"Unevictable: %8lu kB\n"
+ "Mlocked: %8lu kB\n"
#endif
#ifdef CONFIG_HIGHMEM
"HighTotal: %8lu kB\n"
@@ -217,6 +218,7 @@
K(pages[LRU_INACTIVE_FILE]),
#ifdef CONFIG_UNEVICTABLE_LRU
K(pages[LRU_UNEVICTABLE]),
+ K(global_page_state(NR_MLOCK)),
#endif
#ifdef CONFIG_HIGHMEM
K(i.totalhigh),
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index d1f60d5..da2d053 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -88,8 +88,10 @@
NR_ACTIVE_FILE, /* " " " " " */
#ifdef CONFIG_UNEVICTABLE_LRU
NR_UNEVICTABLE, /* " " " " " */
+ NR_MLOCK, /* mlock()ed pages found and moved off LRU */
#else
NR_UNEVICTABLE = NR_ACTIVE_FILE, /* avoid compiler errors in dead code */
+ NR_MLOCK = NR_ACTIVE_FILE,
#endif
NR_ANON_PAGES, /* Mapped anonymous pages */
NR_FILE_MAPPED, /* pagecache pages mapped into pagetables.
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 135840c..05b8050 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -45,6 +45,10 @@
UNEVICTABLE_PGCULLED, /* culled to noreclaim list */
UNEVICTABLE_PGSCANNED, /* scanned for reclaimability */
UNEVICTABLE_PGRESCUED, /* rescued from noreclaim list */
+ UNEVICTABLE_PGMLOCKED,
+ UNEVICTABLE_PGMUNLOCKED,
+ UNEVICTABLE_PGCLEARED, /* on COW, page truncate */
+ UNEVICTABLE_PGSTRANDED, /* unable to isolate on unlock */
#endif
NR_VM_EVENT_ITEMS
};
diff --git a/mm/internal.h b/mm/internal.h
index 48e32f7..1cfbf2e 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -101,7 +101,10 @@
if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED))
return 0;
- SetPageMlocked(page);
+ if (!TestSetPageMlocked(page)) {
+ inc_zone_page_state(page, NR_MLOCK);
+ count_vm_event(UNEVICTABLE_PGMLOCKED);
+ }
return 1;
}
@@ -128,12 +131,19 @@
/*
* mlock_migrate_page - called only from migrate_page_copy() to
- * migrate the Mlocked page flag
+ * migrate the Mlocked page flag; update statistics.
*/
static inline void mlock_migrate_page(struct page *newpage, struct page *page)
{
- if (TestClearPageMlocked(page))
+ if (TestClearPageMlocked(page)) {
+ unsigned long flags;
+
+ local_irq_save(flags);
+ __dec_zone_page_state(page, NR_MLOCK);
SetPageMlocked(newpage);
+ __inc_zone_page_state(newpage, NR_MLOCK);
+ local_irq_restore(flags);
+ }
}
diff --git a/mm/mlock.c b/mm/mlock.c
index 8b47835..bce1b22 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -60,6 +60,8 @@
return;
}
+ dec_zone_page_state(page, NR_MLOCK);
+ count_vm_event(UNEVICTABLE_PGCLEARED);
if (!isolate_lru_page(page)) {
putback_lru_page(page);
} else {
@@ -69,6 +71,9 @@
lru_add_drain_all();
if (!isolate_lru_page(page))
putback_lru_page(page);
+ else if (PageUnevictable(page))
+ count_vm_event(UNEVICTABLE_PGSTRANDED);
+
}
}
@@ -80,8 +85,12 @@
{
BUG_ON(!PageLocked(page));
- if (!TestSetPageMlocked(page) && !isolate_lru_page(page))
- putback_lru_page(page);
+ if (!TestSetPageMlocked(page)) {
+ inc_zone_page_state(page, NR_MLOCK);
+ count_vm_event(UNEVICTABLE_PGMLOCKED);
+ if (!isolate_lru_page(page))
+ putback_lru_page(page);
+ }
}
/*
@@ -106,9 +115,31 @@
{
BUG_ON(!PageLocked(page));
- if (TestClearPageMlocked(page) && !isolate_lru_page(page)) {
- try_to_munlock(page);
- putback_lru_page(page);
+ if (TestClearPageMlocked(page)) {
+ dec_zone_page_state(page, NR_MLOCK);
+ if (!isolate_lru_page(page)) {
+ int ret = try_to_munlock(page);
+ /*
+ * did try_to_unlock() succeed or punt?
+ */
+ if (ret == SWAP_SUCCESS || ret == SWAP_AGAIN)
+ count_vm_event(UNEVICTABLE_PGMUNLOCKED);
+
+ putback_lru_page(page);
+ } else {
+ /*
+ * We lost the race. let try_to_unmap() deal
+ * with it. At least we get the page state and
+ * mlock stats right. However, page is still on
+ * the noreclaim list. We'll fix that up when
+ * the page is eventually freed or we scan the
+ * noreclaim list.
+ */
+ if (PageUnevictable(page))
+ count_vm_event(UNEVICTABLE_PGSTRANDED);
+ else
+ count_vm_event(UNEVICTABLE_PGMUNLOCKED);
+ }
}
}
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 6db2f63..9e28abc 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -625,6 +625,7 @@
"nr_active_file",
#ifdef CONFIG_UNEVICTABLE_LRU
"nr_unevictable",
+ "nr_mlock",
#endif
"nr_anon_pages",
"nr_mapped",
@@ -684,6 +685,10 @@
"unevictable_pgs_culled",
"unevictable_pgs_scanned",
"unevictable_pgs_rescued",
+ "unevictable_pgs_mlocked",
+ "unevictable_pgs_munlocked",
+ "unevictable_pgs_cleared",
+ "unevictable_pgs_stranded",
#endif
#endif
};