On Fri, Sep 9, 2022 at 7:29 AM Laurent Dufour [off-list ref] wrote:

Le 01/09/2022 à 19:35, Suren Baghdasaryan a écrit :

quoted

Add a new CONFIG_PER_VMA_LOCK_STATS config option to dump extra
statistics about handling page fault under VMA lock.

Why not making this a default when per VMA lock are enabled?

Good idea. If no objections I'll make that change.

quoted

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 include/linux/vm_event_item.h | 6 ++++++
 include/linux/vmstat.h        | 6 ++++++
 mm/Kconfig.debug              | 8 ++++++++
 mm/vmstat.c                   | 6 ++++++
 4 files changed, 26 insertions(+)

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index f3fc36cd2276..a325783ed05d 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h

@@ -150,6 +150,12 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 #ifdef CONFIG_X86
              DIRECT_MAP_LEVEL2_SPLIT,
              DIRECT_MAP_LEVEL3_SPLIT,
+#endif
+#ifdef CONFIG_PER_VMA_LOCK_STATS
+             VMA_LOCK_SUCCESS,
+             VMA_LOCK_ABORT,
+             VMA_LOCK_RETRY,
+             VMA_LOCK_MISS,
 #endif
              NR_VM_EVENT_ITEMS
 };

diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index bfe38869498d..0c2611899cfc 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h

@@ -131,6 +131,12 @@ static inline void vm_events_fold_cpu(int cpu)
 #define count_vm_vmacache_event(x) do {} while (0)
 #endif

+#ifdef CONFIG_PER_VMA_LOCK_STATS
+#define count_vm_vma_lock_event(x) count_vm_event(x)
+#else
+#define count_vm_vma_lock_event(x) do {} while (0)
+#endif
+
 #define __count_zid_vm_events(item, zid, delta) \
      __count_vm_events(item##_NORMAL - ZONE_NORMAL + zid, delta)

diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug
index ce8dded36de9..075642763a03 100644
--- a/mm/Kconfig.debug
+++ b/mm/Kconfig.debug

@@ -207,3 +207,11 @@ config PTDUMP_DEBUGFS
        kernel.

        If in doubt, say N.
+
+
+config PER_VMA_LOCK_STATS
+     bool "Statistics for per-vma locks"
+     depends on PER_VMA_LOCK
+     help
+       Statistics for per-vma locks.
+       If in doubt, say N.

diff --git a/mm/vmstat.c b/mm/vmstat.c
index 90af9a8572f5..3f3804c846a6 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c

@@ -1411,6 +1411,12 @@ const char * const vmstat_text[] = {
      "direct_map_level2_splits",
      "direct_map_level3_splits",
 #endif
+#ifdef CONFIG_PER_VMA_LOCK_STATS
+     "vma_lock_success",
+     "vma_lock_abort",
+     "vma_lock_retry",
+     "vma_lock_miss",
+#endif
 #endif /* CONFIG_VM_EVENT_COUNTERS || CONFIG_MEMCG */
 };
 #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA || CONFIG_MEMCG */