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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/x86
parent871341023c771ad233620b7a1fb3d9c7031c4e5c (diff)
downloadop-kernel-dev-759496ba6407c6994d6a5ce3a5e74937d7816208.zip
op-kernel-dev-759496ba6407c6994d6a5ce3a5e74937d7816208.tar.gz
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/x86')
-rw-r--r--arch/x86/mm/fault.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 654be4a..6d77c38 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1011,9 +1011,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code)
unsigned long address;
struct mm_struct *mm;
int fault;
- int write = error_code & PF_WRITE;
- unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
- (write ? FAULT_FLAG_WRITE : 0);
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
tsk = current;
mm = tsk->mm;
@@ -1083,6 +1081,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code)
if (user_mode_vm(regs)) {
local_irq_enable();
error_code |= PF_USER;
+ flags |= FAULT_FLAG_USER;
} else {
if (regs->flags & X86_EFLAGS_IF)
local_irq_enable();
@@ -1109,6 +1108,9 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code)
return;
}
+ if (error_code & PF_WRITE)
+ flags |= FAULT_FLAG_WRITE;
+
/*
* When running in the kernel we expect faults to occur only to
* addresses in user space. All other faults represent errors in
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