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, 116 deletions

diff --git a/mm/nommu.c b/mm/nommu.c
index 9bdf8b1..6402f27 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -47,33 +47,11 @@ struct page *mem_map;
 unsigned long max_mapnr;
 EXPORT_SYMBOL(max_mapnr);
 unsigned long highest_memmap_pfn;
-struct percpu_counter vm_committed_as;
-int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
-int sysctl_overcommit_ratio = 50; /* default is 50% */
-unsigned long sysctl_overcommit_kbytes __read_mostly;
-int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
 int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
-unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */
-unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */
 int heap_stack_gap = 0;
 
 atomic_long_t mmap_pages_allocated;
 
-/*
- * 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);
-
 EXPORT_SYMBOL(mem_map);
 
 /* list of mapped, potentially shareable regions */
@@ -1828,100 +1806,6 @@ void unmap_mapping_range(struct address_space *mapping,
 }
 EXPORT_SYMBOL(unmap_mapping_range);
 
-/*
- * 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_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 3% 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;
-}
-
 int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	BUG();