diff options
Diffstat (limited to 'mm/nommu.c')
| -rw-r--r-- | mm/nommu.c | 68 |
1 files changed, 57 insertions, 11 deletions
diff --git a/mm/nommu.c b/mm/nommu.c index e001768b14e8..fbe3e2f317eb 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -63,6 +63,8 @@ int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */ int sysctl_overcommit_ratio = 50; /* default is 50% */ 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; @@ -228,8 +230,7 @@ int follow_pfn(struct vm_area_struct *vma, unsigned long address, } EXPORT_SYMBOL(follow_pfn); -DEFINE_RWLOCK(vmlist_lock); -struct vm_struct *vmlist; +LIST_HEAD(vmap_area_list); void vfree(const void *addr) { @@ -1898,7 +1899,7 @@ EXPORT_SYMBOL(unmap_mapping_range); */ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) { - unsigned long free, allowed; + unsigned long free, allowed, reserve; vm_acct_memory(pages); @@ -1939,10 +1940,10 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) free -= totalreserve_pages; /* - * Leave the last 3% for root + * Reserve some for root */ if (!cap_sys_admin) - free -= free / 32; + free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10); if (free > pages) return 0; @@ -1952,16 +1953,19 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) allowed = totalram_pages * sysctl_overcommit_ratio / 100; /* - * Leave the last 3% for root + * Reserve some 3% for root */ if (!cap_sys_admin) - allowed -= allowed / 32; + allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10); allowed += total_swap_pages; - /* Don't let a single process grow too big: - leave 3% of the size of this process for other processes */ - if (mm) - allowed -= mm->total_vm / 32; + /* + * 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(mm->total_vm / 32, reserve); + } if (percpu_counter_read_positive(&vm_committed_as) < allowed) return 0; @@ -2123,3 +2127,45 @@ int nommu_shrink_inode_mappings(struct inode *inode, size_t size, up_write(&nommu_region_sem); return 0; } + +/* + * Initialise sysctl_user_reserve_kbytes. + * + * This is intended to prevent a user from starting a single memory hogging + * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER + * mode. + * + * The default value is min(3% of free memory, 128MB) + * 128MB is enough to recover with sshd/login, bash, and top/kill. + */ +static int __meminit init_user_reserve(void) +{ + unsigned long free_kbytes; + + free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); + + sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17); + return 0; +} +module_init(init_user_reserve) + +/* + * Initialise sysctl_admin_reserve_kbytes. + * + * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin + * to log in and kill a memory hogging process. + * + * Systems with more than 256MB will reserve 8MB, enough to recover + * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will + * only reserve 3% of free pages by default. + */ +static int __meminit init_admin_reserve(void) +{ + unsigned long free_kbytes; + + free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); + + sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); + return 0; +} +module_init(init_admin_reserve) |