mm: rework virtual memory accounting
When inspecting a vague code inside prctl(PR_SET_MM_MEM) call (which
testing the RLIMIT_DATA value to figure out if we're allowed to assign
new @start_brk, @brk, @start_data, @end_data from mm_struct) it's been
commited that RLIMIT_DATA in a form it's implemented now doesn't do
anything useful because most of user-space libraries use mmap() syscall
for dynamic memory allocations.
Linus suggested to convert RLIMIT_DATA rlimit into something suitable
for anonymous memory accounting. But in this patch we go further, and
the changes are bundled together as:
* keep vma counting if CONFIG_PROC_FS=n, will be used for limits
* replace mm->shared_vm with better defined mm->data_vm
* account anonymous executable areas as executable
* account file-backed growsdown/up areas as stack
* drop struct file* argument from vm_stat_account
* enforce RLIMIT_DATA for size of data areas
This way code looks cleaner: now code/stack/data classification depends
only on vm_flags state:
VM_EXEC & ~VM_WRITE -> code (VmExe + VmLib in proc)
VM_GROWSUP | VM_GROWSDOWN -> stack (VmStk)
VM_WRITE & ~VM_SHARED & !stack -> data (VmData)
The rest (VmSize - VmData - VmStk - VmExe - VmLib) could be called
"shared", but that might be strange beast like readonly-private or VM_IO
area.
- RLIMIT_AS limits whole address space "VmSize"
- RLIMIT_STACK limits stack "VmStk" (but each vma individually)
- RLIMIT_DATA now limits "VmData"
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Kees Cook <keescook@google.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/mremap.c b/mm/mremap.c
index de824e7..e55b157 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -317,7 +317,7 @@
* If this were a serious issue, we'd add a flag to do_munmap().
*/
hiwater_vm = mm->hiwater_vm;
- vm_stat_account(mm, vma->vm_flags, vma->vm_file, new_len>>PAGE_SHIFT);
+ vm_stat_account(mm, vma->vm_flags, new_len >> PAGE_SHIFT);
/* Tell pfnmap has moved from this vma */
if (unlikely(vma->vm_flags & VM_PFNMAP))
@@ -383,7 +383,8 @@
return ERR_PTR(-EAGAIN);
}
- if (!may_expand_vm(mm, (new_len - old_len) >> PAGE_SHIFT))
+ if (!may_expand_vm(mm, vma->vm_flags,
+ (new_len - old_len) >> PAGE_SHIFT))
return ERR_PTR(-ENOMEM);
if (vma->vm_flags & VM_ACCOUNT) {
@@ -545,7 +546,7 @@
goto out;
}
- vm_stat_account(mm, vma->vm_flags, vma->vm_file, pages);
+ vm_stat_account(mm, vma->vm_flags, pages);
if (vma->vm_flags & VM_LOCKED) {
mm->locked_vm += pages;
locked = true;
