mm: add VM counters for transparent hugepages
I found it difficult to make sense of transparent huge pages without
having any counters for its actions. Add some counters to vmstat for
allocation of transparent hugepages and fallback to smaller pages.
Optional patch, but useful for development and understanding the system.
Contains improvements from Andrea Arcangeli and Johannes Weiner
[akpm@linux-foundation.org: coding-style fixes]
[hannes@cmpxchg.org: fix vmstat_text[] entries]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 461c011..2b3831b 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -58,6 +58,13 @@
UNEVICTABLE_PGCLEARED, /* on COW, page truncate */
UNEVICTABLE_PGSTRANDED, /* unable to isolate on unlock */
UNEVICTABLE_MLOCKFREED,
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ THP_FAULT_ALLOC,
+ THP_FAULT_FALLBACK,
+ THP_COLLAPSE_ALLOC,
+ THP_COLLAPSE_ALLOC_FAILED,
+ THP_SPLIT,
+#endif
NR_VM_EVENT_ITEMS
};
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 0a619e0..1722683 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -680,8 +680,11 @@
return VM_FAULT_OOM;
page = alloc_hugepage_vma(transparent_hugepage_defrag(vma),
vma, haddr, numa_node_id(), 0);
- if (unlikely(!page))
+ if (unlikely(!page)) {
+ count_vm_event(THP_FAULT_FALLBACK);
goto out;
+ }
+ count_vm_event(THP_FAULT_ALLOC);
if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) {
put_page(page);
goto out;
@@ -909,11 +912,13 @@
new_page = NULL;
if (unlikely(!new_page)) {
+ count_vm_event(THP_FAULT_FALLBACK);
ret = do_huge_pmd_wp_page_fallback(mm, vma, address,
pmd, orig_pmd, page, haddr);
put_page(page);
goto out;
}
+ count_vm_event(THP_FAULT_ALLOC);
if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) {
put_page(new_page);
@@ -1390,6 +1395,7 @@
BUG_ON(!PageSwapBacked(page));
__split_huge_page(page, anon_vma);
+ count_vm_event(THP_SPLIT);
BUG_ON(PageCompound(page));
out_unlock:
@@ -1784,9 +1790,11 @@
node, __GFP_OTHER_NODE);
if (unlikely(!new_page)) {
up_read(&mm->mmap_sem);
+ count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
*hpage = ERR_PTR(-ENOMEM);
return;
}
+ count_vm_event(THP_COLLAPSE_ALLOC);
if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) {
up_read(&mm->mmap_sem);
put_page(new_page);
@@ -2151,8 +2159,11 @@
#ifndef CONFIG_NUMA
if (!*hpage) {
*hpage = alloc_hugepage(khugepaged_defrag());
- if (unlikely(!*hpage))
+ if (unlikely(!*hpage)) {
+ count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
break;
+ }
+ count_vm_event(THP_COLLAPSE_ALLOC);
}
#else
if (IS_ERR(*hpage))
@@ -2192,8 +2203,11 @@
do {
hpage = alloc_hugepage(khugepaged_defrag());
- if (!hpage)
+ if (!hpage) {
+ count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
khugepaged_alloc_sleep();
+ } else
+ count_vm_event(THP_COLLAPSE_ALLOC);
} while (unlikely(!hpage) &&
likely(khugepaged_enabled()));
return hpage;
@@ -2210,8 +2224,11 @@
while (likely(khugepaged_enabled())) {
#ifndef CONFIG_NUMA
hpage = khugepaged_alloc_hugepage();
- if (unlikely(!hpage))
+ if (unlikely(!hpage)) {
+ count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
break;
+ }
+ count_vm_event(THP_COLLAPSE_ALLOC);
#else
if (IS_ERR(hpage)) {
khugepaged_alloc_sleep();
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 8cb0f0a..897ea9e 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -948,7 +948,16 @@
"unevictable_pgs_cleared",
"unevictable_pgs_stranded",
"unevictable_pgs_mlockfreed",
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ "thp_fault_alloc",
+ "thp_fault_fallback",
+ "thp_collapse_alloc",
+ "thp_collapse_alloc_failed",
+ "thp_split",
#endif
+
+#endif /* CONFIG_VM_EVENTS_COUNTERS */
};
static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,