Messages in this thread | | | Date | Wed, 23 Mar 2011 16:49:49 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [PATCH 5/5] x86,mm: make pagefault killable |
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On Tue, 22 Mar 2011 20:09:29 +0900 (JST) KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:
> When oom killer occured, almost processes are getting stuck following > two points. > > 1) __alloc_pages_nodemask > 2) __lock_page_or_retry > > 1) is not much problematic because TIF_MEMDIE lead to make allocation > failure and get out from page allocator. 2) is more problematic. When > OOM situation, Zones typically don't have page cache at all and Memory > starvation might lead to reduce IO performance largely. When fork bomb > occur, TIF_MEMDIE task don't die quickly mean fork bomb may create > new process quickly rather than oom-killer kill it. Then, the system > may become livelock. > > This patch makes pagefault interruptible by SIGKILL. > > Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> > --- > arch/x86/mm/fault.c | 9 +++++++++ > include/linux/mm.h | 1 + > mm/filemap.c | 22 +++++++++++++++++----- > 3 files changed, 27 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c > index 20e3f87..797c7d0 100644 > --- a/arch/x86/mm/fault.c > +++ b/arch/x86/mm/fault.c > @@ -1035,6 +1035,7 @@ 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_KILLABLE; > } else { > if (regs->flags & X86_EFLAGS_IF) > local_irq_enable(); > @@ -1138,6 +1139,14 @@ good_area: > } > > /* > + * Pagefault was interrupted by SIGKILL. We have no reason to > + * continue pagefault. > + */ > + if ((flags & FAULT_FLAG_KILLABLE) && (fault & VM_FAULT_RETRY) && > + fatal_signal_pending(current)) > + return; > +
Hmm? up_read(&mm->mmap_sem) ?
Thanks, -Kame
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