VM_ACCT
0 : security_vm_enough_memory_mm(current->mm, VM_ACCT(size));
vm_unacct_memory(VM_ACCT(size));
if (VM_ACCT(newsize) > VM_ACCT(oldsize))
VM_ACCT(newsize) - VM_ACCT(oldsize));
else if (VM_ACCT(newsize) < VM_ACCT(oldsize))
vm_unacct_memory(VM_ACCT(oldsize) - VM_ACCT(newsize));
pages * VM_ACCT(PAGE_SIZE));
vm_unacct_memory(pages * VM_ACCT(PAGE_SIZE));