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-rw-r--r--mm/vmacache.c22
1 files changed, 20 insertions, 2 deletions
diff --git a/mm/vmacache.c b/mm/vmacache.c
index 1037a3bab505..9f25af825dec 100644
--- a/mm/vmacache.c
+++ b/mm/vmacache.c
@@ -17,6 +17,16 @@ void vmacache_flush_all(struct mm_struct *mm)
{
struct task_struct *g, *p;
+ /*
+ * Single threaded tasks need not iterate the entire
+ * list of process. We can avoid the flushing as well
+ * since the mm's seqnum was increased and don't have
+ * to worry about other threads' seqnum. Current's
+ * flush will occur upon the next lookup.
+ */
+ if (atomic_read(&mm->mm_users) == 1)
+ return;
+
rcu_read_lock();
for_each_process_thread(g, p) {
/*
@@ -78,6 +88,8 @@ 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 +97,10 @@ 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 +116,15 @@ 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;