mm: deduplicate memory overcommitment code

Currently we have two copies of the same code which implements memory
overcommitment logic.  Let's move it into mm/util.c and hence avoid
duplication.  No functional changes here.

Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 124 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index 676f422f2e2c..14641926c97f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -122,130 +122,6 @@ void vma_set_page_prot(struct vm_area_struct *vma)
         }
 }
 
-
-int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS;  /* heuristic overcommit */
-int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */
-unsigned long sysctl_overcommit_kbytes __read_mostly;
-int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
-unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */
-unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */
-/*
- * 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;
-
-/*
- * The global memory commitment made in the system can be a metric
- * that can be used to drive ballooning decisions when Linux is hosted
- * as a guest. On Hyper-V, the host implements a policy engine for dynamically
- * balancing memory across competing virtual machines that are hosted.
- * Several metrics drive this policy engine including the guest reported
- * memory commitment.
- */
-unsigned long vm_memory_committed(void)
-{
-        return percpu_counter_read_positive(&vm_committed_as);
-}
-EXPORT_SYMBOL_GPL(vm_memory_committed);
-
-/*
- * Check that a process has enough memory to allocate a new virtual
- * mapping. 0 means there is enough memory for the allocation to
- * succeed and -ENOMEM implies there is not.
- *
- * We currently support three overcommit policies, which are set via the
- * vm.overcommit_memory sysctl.  See Documentation/vm/overcommit-accounting
- *
- * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
- * Additional code 2002 Jul 20 by Robert Love.
- *
- * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
- *
- * Note this is a helper function intended to be used by LSMs which
- * wish to use this logic.
- */
-int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
-{
-        long free, allowed, reserve;
-
-        VM_WARN_ONCE(percpu_counter_read(&vm_committed_as) <
-                        -(s64)vm_committed_as_batch * num_online_cpus(),
-                        "memory commitment underflow");
-
-        vm_acct_memory(pages);
-
-        /*
-         * Sometimes we want to use more memory than we have
-         */
-        if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
-                return 0;
-
-        if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
-                free = global_page_state(NR_FREE_PAGES);
-                free += global_page_state(NR_FILE_PAGES);
-
-                /*
-                 * shmem pages shouldn't be counted as free in this
-                 * case, they can't be purged, only swapped out, and
-                 * that won't affect the overall amount of available
-                 * memory in the system.
-                 */
-                free -= global_page_state(NR_SHMEM);
-
-                free += get_nr_swap_pages();
-
-                /*
-                 * Any slabs which are created with the
-                 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
-                 * which are reclaimable, under pressure.  The dentry
-                 * cache and most inode caches should fall into this
-                 */
-                free += global_page_state(NR_SLAB_RECLAIMABLE);
-
-                /*
-                 * Leave reserved pages. The pages are not for anonymous pages.
-                 */
-                if (free <= totalreserve_pages)
-                        goto error;
-                else
-                        free -= totalreserve_pages;
-
-                /*
-                 * Reserve some for root
-                 */
-                if (!cap_sys_admin)
-                        free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
-
-                if (free > pages)
-                        return 0;
-
-                goto error;
-        }
-
-        allowed = vm_commit_limit();
-        /*
-         * Reserve some for root
-         */
-        if (!cap_sys_admin)
-                allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
-
-        /*
-         * Don't let a single process grow so big a user can't recover
-         */
-        if (mm) {
-                reserve = sysctl_user_reserve_kbytes >> (PAGE_SHIFT - 10);
-                allowed -= min_t(long, mm->total_vm / 32, reserve);
-        }
-
-        if (percpu_counter_read_positive(&vm_committed_as) < allowed)
-                return 0;
-error:
-        vm_unacct_memory(pages);
-
-        return -ENOMEM;
-}
-
 /*
  * Requires inode->i_mapping->i_mmap_rwsem
  */