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authorJohannes Weiner <hannes@cmpxchg.org>2013-09-12 15:13:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-12 15:38:01 -0700
commit759496ba6407c6994d6a5ce3a5e74937d7816208 (patch)
treeaeff8de8af36f70f2591114cef58c9ae7df25565 /arch/microblaze
parent871341023c771ad233620b7a1fb3d9c7031c4e5c (diff)
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>
Diffstat (limited to 'arch/microblaze')
-rw-r--r--arch/microblaze/mm/fault.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/microblaze/mm/fault.c b/arch/microblaze/mm/fault.c
index 731f739d17a1..fa4cf52aa7a6 100644
--- a/arch/microblaze/mm/fault.c
+++ b/arch/microblaze/mm/fault.c
@@ -92,8 +92,7 @@ void do_page_fault(struct pt_regs *regs, unsigned long address,
int code = SEGV_MAPERR;
int is_write = error_code & ESR_S;
int fault;
- unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
- (is_write ? FAULT_FLAG_WRITE : 0);
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
regs->ear = address;
regs->esr = error_code;
@@ -121,6 +120,9 @@ void do_page_fault(struct pt_regs *regs, unsigned long address,
die("Weird page fault", regs, SIGSEGV);
}
+ if (user_mode(regs))
+ flags |= FAULT_FLAG_USER;
+
/* When running in the kernel we expect faults to occur only to
* addresses in user space. All other faults represent errors in the
* kernel and should generate an OOPS. Unfortunately, in the case of an
@@ -199,6 +201,7 @@ good_area:
if (unlikely(is_write)) {
if (unlikely(!(vma->vm_flags & VM_WRITE)))
goto bad_area;
+ flags |= FAULT_FLAG_WRITE;
/* a read */
} else {
/* protection fault */