int cap_vm_enough_memory(long pages)
{
int cap_sys_admin = 0;
if (cap_capable(current, CAP_SYS_ADMIN) == 0)
cap_sys_admin = 1;
return __vm_enough_memory(pages, cap_sys_admin);
}
static int dummy_vm_enough_memory(struct mm_struct *mm, long pages)
{
int cap_sys_admin = 0;
if (dummy_capable(current, CAP_SYS_ADMIN) == 0)
cap_sys_admin = 1;
return __vm_enough_memory(mm, pages, cap_sys_admin);
}
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;
}
