From 39a1aa8e194ab67983de3b9d0b204ccee12e689a Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Thu, 17 Mar 2016 14:18:50 -0700 Subject: 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/nommu.c | 116 ------------------------------------------------------------- 1 file changed, 116 deletions(-) (limited to 'mm/nommu.c') diff --git a/mm/nommu.c b/mm/nommu.c index 9bdf8b119078..6402f2715d48 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(); -- cgit v1.2.3