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authorKonstantin Khlebnikov <koct9i@gmail.com>2016-01-14 15:22:07 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-14 16:00:49 -0800
commit84638335900f1995495838fe1bd4870c43ec1f67 (patch)
tree8983e891fcf8320408c8ff2c6137f27ce553ba5a /mm/mprotect.c
parentd30b5545bdcf802ffc24ec7dbc6dc4036f6e3820 (diff)
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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>
Diffstat (limited to 'mm/mprotect.c')
-rw-r--r--mm/mprotect.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/mm/mprotect.c b/mm/mprotect.c
index ef5be8eaab00..c764402c464f 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -278,6 +278,10 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
* even if read-only so there is no need to account for them here
*/
if (newflags & VM_WRITE) {
+ /* Check space limits when area turns into data. */
+ if (!may_expand_vm(mm, newflags, nrpages) &&
+ may_expand_vm(mm, oldflags, nrpages))
+ return -ENOMEM;
if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
VM_SHARED|VM_NORESERVE))) {
charged = nrpages;
@@ -334,8 +338,8 @@ success:
populate_vma_page_range(vma, start, end, NULL);
}
- vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
- vm_stat_account(mm, newflags, vma->vm_file, nrpages);
+ vm_stat_account(mm, oldflags, -nrpages);
+ vm_stat_account(mm, newflags, nrpages);
perf_event_mmap(vma);
return 0;