commit 458083c18d7fd280521f322dba58d305e431eef6
author Andi Kleen <ak@linux.intel.com> Thu Jul 31 17:48:15 2014 -0700
committer Andi Kleen <ak@linux.intel.com> Tue Aug 19 08:20:30 2014 -0700
tree 31d4c0bcfee0207091dd1366e9d44bb2673d1971
parent 67517bf6a04240e0ce3fb30a7e027247a3c75eb5

instrument mmap slow path (testing only)

mm/mmap.c

diff --git a/mm/mmap.c b/mm/mmap.c
index 5cd2b88..501551b 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -24,6 +24,7 @@
 #include <linux/security.h>
 #include <linux/hugetlb.h>
 #include <linux/profile.h>
+#include <linux/moduleparam.h>
 #include <linux/export.h>
 #include <linux/mount.h>
 #include <linux/mempolicy.h>
@@ -112,6 +113,11 @@
 }
 EXPORT_SYMBOL_GPL(vm_memory_committed);
 
+static DEFINE_PER_CPU(long, stat_vem_total);
+module_param_cb(vem_total, &param_ops_percpu_uint, &stat_vem_total, 0644);
+static DEFINE_PER_CPU(long, stat_vem_slow);
+module_param_cb(vem_slow, &param_ops_percpu_uint, &stat_vem_slow, 0644);
+
 /*
  * Check that a process has enough memory to allocate a new virtual
  * mapping. 0 means there is enough memory for the allocation to
@@ -143,6 +149,8 @@
 	if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
 		long extra = totalreserve_pages;
 
+		__this_cpu_inc(stat_vem_total);
+
 		/*
 		 * Reserve some for root
 		 */
@@ -166,6 +174,8 @@
 
 		/* Slow path. */
 
+		__this_cpu_inc(stat_vem_slow);
+
 		free = global_page_state(NR_FREE_PAGES);
 		free += global_page_state(NR_FILE_PAGES);