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authorDavidlohr Bueso <davidlohr@hp.com>2014-06-04 16:06:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-04 16:53:57 -0700
commit4f115147ff802267d0aa41e361c5aa5bd933d896 (patch)
tree27afdf3f60c21fde601df63d9e9998b0c758a3fe /mm/vmacache.c
parent6f04f48dc9c0433e2bb687f5f7f7af1aba97b04d (diff)
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mm,vmacache: add debug data
Introduce a CONFIG_DEBUG_VM_VMACACHE option to enable counting the cache hit rate -- exported in /proc/vmstat. Any updates to the caching scheme needs this kind of data, thus it can save some work re-implementing the counting all the time. Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Cc: Aswin Chandramouleeswaran <aswin@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmacache.c')
-rw-r--r--mm/vmacache.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/mm/vmacache.c b/mm/vmacache.c
index 1037a3bab505..658ed3b3e38d 100644
--- a/mm/vmacache.c
+++ b/mm/vmacache.c
@@ -78,6 +78,8 @@ struct vm_area_struct *vmacache_find(struct mm_struct *mm, unsigned long addr)
if (!vmacache_valid(mm))
return NULL;
+ count_vm_vmacache_event(VMACACHE_FIND_CALLS);
+
for (i = 0; i < VMACACHE_SIZE; i++) {
struct vm_area_struct *vma = current->vmacache[i];
@@ -85,8 +87,10 @@ struct vm_area_struct *vmacache_find(struct mm_struct *mm, unsigned long addr)
continue;
if (WARN_ON_ONCE(vma->vm_mm != mm))
break;
- if (vma->vm_start <= addr && vma->vm_end > addr)
+ if (vma->vm_start <= addr && vma->vm_end > addr) {
+ count_vm_vmacache_event(VMACACHE_FIND_HITS);
return vma;
+ }
}
return NULL;
@@ -102,11 +106,15 @@ struct vm_area_struct *vmacache_find_exact(struct mm_struct *mm,
if (!vmacache_valid(mm))
return NULL;
+ count_vm_vmacache_event(VMACACHE_FIND_CALLS);
+
for (i = 0; i < VMACACHE_SIZE; i++) {
struct vm_area_struct *vma = current->vmacache[i];
- if (vma && vma->vm_start == start && vma->vm_end == end)
+ if (vma && vma->vm_start == start && vma->vm_end == end) {
+ count_vm_vmacache_event(VMACACHE_FIND_HITS);
return vma;
+ }
}
return NULL;