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| author | Johannes Weiner <hannes@cmpxchg.org> | 2013-09-12 15:13:39 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-21 09:22:56 -0800 |
| commit | e2ec2c2b96808afa2f57ec7d7949691146fca341 (patch) | |
| tree | 9056b3be2fc19f9a00993a01507776a97b7d3ebd /arch/arc/mm | |
| parent | 086c6cc5377d0908667e8f7082633aebf45cf95f (diff) | |
| download | lwn-e2ec2c2b96808afa2f57ec7d7949691146fca341.tar.gz lwn-e2ec2c2b96808afa2f57ec7d7949691146fca341.zip | |
arch: mm: pass userspace fault flag to generic fault handler
commit 759496ba6407c6994d6a5ce3a5e74937d7816208 upstream.
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: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arc/mm')
| -rw-r--r-- | arch/arc/mm/fault.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c index 87f4281a4b64..50533b750a99 100644 --- a/arch/arc/mm/fault.c +++ b/arch/arc/mm/fault.c @@ -59,8 +59,7 @@ void do_page_fault(struct pt_regs *regs, int write, unsigned long address, struct mm_struct *mm = tsk->mm; siginfo_t info; int fault, ret; - 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; /* * We fault-in kernel-space virtual memory on-demand. The @@ -88,6 +87,8 @@ void do_page_fault(struct pt_regs *regs, int write, unsigned long address, if (in_atomic() || !mm) goto no_context; + if (user_mode(regs)) + flags |= FAULT_FLAG_USER; retry: down_read(&mm->mmap_sem); vma = find_vma(mm, address); @@ -115,6 +116,7 @@ good_area: if (write) { if (!(vma->vm_flags & VM_WRITE)) goto bad_area; + flags |= FAULT_FLAG_WRITE; } else { if (!(vma->vm_flags & (VM_READ | VM_EXEC))) goto bad_area; |