mm: factor commit limit calculation

The same calculation is currently done in three differents places.
Factor that code so future changes has to be made at only one place.

[akpm@linux-foundation.org: uninline vm_commit_limit()]
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

5 files changed, 18 insertions, 9 deletions

diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
index 59d85d608898..c805d5b69ba1 100644
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -24,7 +24,6 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
 {
         struct sysinfo i;
         unsigned long committed;
-        unsigned long allowed;
         struct vmalloc_info vmi;
         long cached;
         unsigned long pages[NR_LRU_LISTS];
@@ -37,8 +36,6 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
         si_meminfo(&i);
         si_swapinfo(&i);
         committed = percpu_counter_read_positive(&vm_committed_as);
-        allowed = ((totalram_pages - hugetlb_total_pages())
-                * sysctl_overcommit_ratio / 100) + total_swap_pages;
 
         cached = global_page_state(NR_FILE_PAGES) -
                         total_swapcache_pages() - i.bufferram;
@@ -147,7 +144,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
                 K(global_page_state(NR_UNSTABLE_NFS)),
                 K(global_page_state(NR_BOUNCE)),
                 K(global_page_state(NR_WRITEBACK_TEMP)),
-                K(allowed),
+                K(vm_commit_limit()),
                 K(committed),
                 (unsigned long)VMALLOC_TOTAL >> 10,
                 vmi.used >> 10,
diff --git a/include/linux/mman.h b/include/linux/mman.h
index 92dc257251e4..7f7f8dae4b1d 100644
--- a/include/linux/mman.h
+++ b/include/linux/mman.h
@@ -87,4 +87,6 @@ calc_vm_flag_bits(unsigned long flags)
                _calc_vm_trans(flags, MAP_DENYWRITE,  VM_DENYWRITE ) |
                _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    );
 }
+
+unsigned long vm_commit_limit(void);
 #endif /* _LINUX_MMAN_H */
diff --git a/mm/mmap.c b/mm/mmap.c
index 3d3e224be771..803048e9c568 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -179,14 +179,12 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
                 goto error;
         }
 
-        allowed = (totalram_pages - hugetlb_total_pages())
-                * sysctl_overcommit_ratio / 100;
+        allowed = vm_commit_limit();
         /*
          * Reserve some for root
          */
         if (!cap_sys_admin)
                 allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
-        allowed += total_swap_pages;
 
         /*
          * Don't let a single process grow so big a user can't recover
diff --git a/mm/nommu.c b/mm/nommu.c
index ecd1f158548e..d8a957bb9e31 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1948,13 +1948,12 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
                 goto error;
         }
 
-        allowed = totalram_pages * sysctl_overcommit_ratio / 100;
+        allowed = vm_commit_limit();
         /*
          * Reserve some 3% for root
          */
         if (!cap_sys_admin)
                 allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
-        allowed += total_swap_pages;
 
         /*
          * Don't let a single process grow so big a user can't recover
diff --git a/mm/util.c b/mm/util.c
index eaf63fc2c92f..f7bc2096071c 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -7,6 +7,9 @@
 #include <linux/security.h>
 #include <linux/swap.h>
 #include <linux/swapops.h>
+#include <linux/mman.h>
+#include <linux/hugetlb.h>
+
 #include <asm/uaccess.h>
 
 #include "internal.h"
@@ -398,6 +401,16 @@ struct address_space *page_mapping(struct page *page)
         return mapping;
 }
 
+/*
+ * Committed memory limit enforced when OVERCOMMIT_NEVER policy is used
+ */
+unsigned long vm_commit_limit(void)
+{
+        return ((totalram_pages - hugetlb_total_pages())
+                * sysctl_overcommit_ratio / 100) + total_swap_pages;
+}
+
+
 /* Tracepoints definitions. */
 EXPORT_TRACEPOINT_SYMBOL(kmalloc);
 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);