arch: mm: pass userspace fault flag to generic fault handler
Unlike global OOM handling, memory cgroup code will invoke the OOM killer
in any OOM situation because it has no way of telling faults occuring in
kernel context - which could be handled more gracefully - from
user-triggered faults.
Pass a flag that identifies faults originating in user space from the
architecture-specific fault handlers to generic code so that memcg OOM
handling can be improved.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: azurIt <azurit@pobox.sk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/frv/mm/fault.c b/arch/frv/mm/fault.c
index 331c1e2..9a66372 100644
--- a/arch/frv/mm/fault.c
+++ b/arch/frv/mm/fault.c
@@ -34,11 +34,11 @@
struct vm_area_struct *vma;
struct mm_struct *mm;
unsigned long _pme, lrai, lrad, fixup;
+ unsigned long flags = 0;
siginfo_t info;
pgd_t *pge;
pud_t *pue;
pte_t *pte;
- int write;
int fault;
#if 0
@@ -81,6 +81,9 @@
if (in_atomic() || !mm)
goto no_context;
+ if (user_mode(__frame))
+ flags |= FAULT_FLAG_USER;
+
down_read(&mm->mmap_sem);
vma = find_vma(mm, ear0);
@@ -129,7 +132,6 @@
*/
good_area:
info.si_code = SEGV_ACCERR;
- write = 0;
switch (esr0 & ESR0_ATXC) {
default:
/* handle write to write protected page */
@@ -140,7 +142,7 @@
#endif
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
- write = 1;
+ flags |= FAULT_FLAG_WRITE;
break;
/* handle read from protected page */
@@ -162,7 +164,7 @@
* make sure we exit gracefully rather than endlessly redo
* the fault.
*/
- fault = handle_mm_fault(mm, vma, ear0, write ? FAULT_FLAG_WRITE : 0);
+ fault = handle_mm_fault(mm, vma, ear0, flags);
if (unlikely(fault & VM_FAULT_ERROR)) {
if (fault & VM_FAULT_OOM)
goto out_of_memory;