Messages in this thread | | | Subject | Re: [PATCH respin, was PATCH for review] During VM oom condition, kill all threads in process group | From | Will Schmidt <> | Date | Tue, 31 Jul 2007 09:55:51 -0500 |
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On Tue, 2007-07-31 at 11:31 +0200, Pavel Machek wrote: > Hi! > > > > > During VM oom condition, kill all threads in process group. > > > > We have had complaints where a threaded application is left in a bad > > state after one of it's threads is killed when we hit a VM: out_of_memory > > condition. > > Killing just one of the process threads can leave the application in a > > bad state, whereas killing the entire process group would allow for > > the application to restart, or be otherwise handled, and makes it very > > obvious that something has gone wrong. > > > > This change allows the entire process group to be taken down, rather > > than just the one thread. > > > > Signed-off-by: Will Schmidt <will_schmidt@vnet.ibm.com> > > > diff --git a/arch/sparc64/mm/fault.c b/arch/sparc64/mm/fault.c > > index 17123e9..13fdfa3 100644 > > --- a/arch/sparc64/mm/fault.c > > +++ b/arch/sparc64/mm/fault.c > > @@ -466,7 +466,7 @@ out_of_memory: > > up_read(&mm->mmap_sem); > > printk("VM: killing process %s\n", current->comm); > > if (!(regs->tstate & TSTATE_PRIV)) > > - do_exit(SIGKILL); > > + do_group_exit(SIGKILL); > > goto handle_kernel_fault; > > > > intr_or_no_mm: > > is the printk still accurate (does it kill more than one process now)?
I was going to double-check this morning.. but don't see where current->comm is copied into a new task_struct. I thought that all processes within the group had the same current->comm value, so figure this is OK.
> Why does it print when it will not really kill the process? no idea..
> I see similar code across all the archs... would it make sense to > create common helper... or is the helper too trivial?
The checks blocking flow into do_group_exit, like (regs->tstate & TSTATE_PRIV) for sparc64, or (user_mode(regs)) for powerpc, do vary across the arch's. The code could be rearranged to have a helper containing just the printk and the do_group_exit() call; but I'm not sure that would be an improvement.
maybe a do_group_sigkill_if(condition); helper :-)
-Will
> Pavel
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