int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
{
unsigned long free, allowed;
vm_acct_memory(pages);
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);
free -= global_page_state(NR_SHMEM);
free += get_nr_swap_pages();
free += global_page_state(NR_SLAB_RECLAIMABLE);
if (free <= totalreserve_pages)
goto error;
else
free -= totalreserve_pages;
if (!cap_sys_admin)
free -= free / 32;
if (free > pages)
return 0;
goto error;
}
allowed = (totalram_pages - hugetlb_total_pages())
* sysctl_overcommit_ratio / 100;
if (!cap_sys_admin)
allowed -= allowed / 32;
allowed += total_swap_pages;
if (mm)
allowed -= mm->total_vm / 32;
if (percpu_counter_read_positive(&vm_committed_as) < allowed)
return 0;
error:
vm_unacct_memory(pages);
return -ENOMEM;
}
/*
* 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
*/
static int dummy_vm_enough_memory(long pages)
{
unsigned long free, allowed;
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 = get_page_cache_size();
free += nr_free_pages();
free += 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 += atomic_read(&slab_reclaim_pages);
/*
* Leave the last 3% for root
*/
if (current->euid)
free -= free / 32;
if (free > pages)
return 0;
vm_unacct_memory(pages);
return -ENOMEM;
}
allowed = (totalram_pages - hugetlb_total_pages())
* sysctl_overcommit_ratio / 100;
allowed += total_swap_pages;
if (atomic_read(&vm_committed_space) < allowed)
return 0;
vm_unacct_memory(pages);
return -ENOMEM;
}
/*
* 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.
*/
int cap_vm_enough_memory(long pages)
{
unsigned long free, allowed;
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) {
unsigned long n;
free = get_page_cache_size();
free += 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 += atomic_read(&slab_reclaim_pages);
/*
* Leave the last 3% for root
*/
if (!capable(CAP_SYS_ADMIN))
free -= free / 32;
if (free > pages)
return 0;
/*
* nr_free_pages() is very expensive on large systems,
* only call if we're about to fail.
*/
n = nr_free_pages();
if (!capable(CAP_SYS_ADMIN))
n -= n / 32;
free += n;
if (free > pages)
return 0;
vm_unacct_memory(pages);
return -ENOMEM;
}
allowed = (totalram_pages - hugetlb_total_pages())
* sysctl_overcommit_ratio / 100;
/*
* Leave the last 3% for root
*/
if (!capable(CAP_SYS_ADMIN))
allowed -= allowed / 32;
allowed += total_swap_pages;
if (atomic_read(&vm_committed_space) < allowed)
return 0;
vm_unacct_memory(pages);
return -ENOMEM;
}
static int low_vm_enough_memory(struct mm_struct *mm, long pages)
{
unsigned long free, allowed;
int cap_sys_admin = 0, notify;
if (cap_capable(current, CAP_SYS_ADMIN) == 0)
cap_sys_admin = 1;
allowed = totalram_pages - hugetlb_total_pages();
allowed_pages = allowed;
/* We activate ourselves only after both parameters have been
* configured. */
if (deny_pages == 0 || notify_low_pages == 0 || notify_high_pages == 0)
return __vm_enough_memory(mm, pages, cap_sys_admin);
vm_acct_memory(pages);
/* Easily freed pages when under VM pressure or direct reclaim */
free = global_page_state(NR_FILE_PAGES);
free += nr_swap_pages;
free += global_page_state(NR_SLAB_RECLAIMABLE);
if (likely(free > notify_low_pages))
goto enough_memory;
/* No luck, lets make it more expensive and try again.. */
free += nr_free_pages();
if (free < deny_pages) {
int i;
lowmem_free_pages = free;
low_watermark_state(1);
high_watermark_state(1);
/* Memory allocations by root are always allowed */
if (cap_sys_admin)
return 0;
/* OOM unkillable process is allowed to consume memory */
if (current->oomkilladj == OOM_DISABLE)
return 0;
/* uids from allowed_uids vector are also allowed no matter what */
for (i = 0; i < LOWMEM_MAX_UIDS && allowed_uids[i]; i++)
if (current->uid == allowed_uids[i])
return 0;
vm_unacct_memory(pages);
if (printk_ratelimit()) {
printk(MY_NAME ": denying memory allocation to process %d (%s)\n",
current->pid, current->comm);
}
return -ENOMEM;
}
enough_memory:
/* See if we need to notify level 1 */
low_watermark_state(free < notify_low_pages);
/*
* In the level 2 notification case things are more complicated,
* as the level that we drop the state and send a notification
* should be lower than when it is first triggered. Having this
* on the same watermark level ends up bouncing back and forth
* when applications are being stupid.
*/
notify = free < notify_high_pages;
if (notify || free - nr_decay_pages > notify_high_pages)
high_watermark_state(notify);
/* We have plenty of memory */
lowmem_free_pages = free;
return 0;
}
/*
* 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)
{
unsigned long free, allowed;
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 += 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;
/*
* Leave the last 3% for root
*/
if (!cap_sys_admin)
free -= free / 32;
if (free > pages)
return 0;
goto error;
}
allowed = (totalram_pages - hugetlb_total_pages())
* sysctl_overcommit_ratio / 100;
/*
* Leave the last 3% for root
*/
if (!cap_sys_admin)
allowed -= allowed / 32;
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;
if (percpu_counter_read_positive(&vm_committed_as) < allowed)
return 0;
error:
vm_unacct_memory(pages);
return -ENOMEM;
}
