mmap: add alignment for some variables

[mv-sheeva.git] / mm / mmap.c

diff --git a/mm/mmap.c b/mm/mmap.c
index e27e0cf0de03ccb81b252953932fc356c3499c10..eaec3df82a2bde37c54102176d143f9827d31fb1 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -84,10 +84,14 @@ pgprot_t vm_get_page_prot(unsigned long vm_flags)
 }
 EXPORT_SYMBOL(vm_get_page_prot);
 
-int sysctl_overcommit_memory = OVERCOMMIT_GUESS;  /* heuristic overcommit */
-int sysctl_overcommit_ratio = 50;      /* default is 50% */
+int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS;  /* heuristic overcommit */
+int sysctl_overcommit_ratio __read_mostly = 50;        /* default is 50% */
 int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
-struct percpu_counter vm_committed_as;
+/*
+ * Make sure vm_committed_as in one cacheline and not cacheline shared with
+ * other variables. It can be updated by several CPUs frequently.
+ */
+struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp;
 
 /*
  * Check that a process has enough memory to allocate a new virtual
@@ -1767,10 +1771,13 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
                size = address - vma->vm_start;
                grow = (address - vma->vm_end) >> PAGE_SHIFT;
 
-               error = acct_stack_growth(vma, size, grow);
-               if (!error) {
-                       vma->vm_end = address;
-                       perf_event_mmap(vma);
+               error = -ENOMEM;
+               if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
+                       error = acct_stack_growth(vma, size, grow);
+                       if (!error) {
+                               vma->vm_end = address;
+                               perf_event_mmap(vma);
+                       }
                }
        }
        vma_unlock_anon_vma(vma);