[PATCH 2/3] mm/vmalloc: Track vmalloc info changes

[Ingo Molnar]

Add a 'vmap_info_changed' flag to track changes to vmalloc()
statistics.

For simplicity this flag is set every time we unlock the
vmap_area_lock.

This flag is not yet used.

Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 mm/vmalloc.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 605138083880..d21febaa557a 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -276,7 +276,9 @@ EXPORT_SYMBOL(vmalloc_to_pfn);
 #define VM_LAZY_FREEING	0x02
 #define VM_VM_AREA	0x04
 
-static DEFINE_SPINLOCK(vmap_area_lock);
+static __cacheline_aligned_in_smp DEFINE_SPINLOCK(vmap_area_lock);
+
+static int vmap_info_changed;
 
 static inline void vmap_lock(void)
 {
@@ -285,6 +287,7 @@ static inline void vmap_lock(void)
 
 static inline void vmap_unlock(void)
 {
+	vmap_info_changed = 1;
 	spin_unlock(&vmap_area_lock);
 }
 
-- 
2.1.4

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