On Fri 26-07-13 14:46:57, Johannes Weiner wrote: > On Fri, Jul 26, 2013 at 03:52:07PM +0200, Michal Hocko wrote: > > On Thu 25-07-13 18:25:36, Johannes Weiner wrote: > > > The x86 fault handler bails in the middle of error handling when the > > > task has a fatal signal pending. For a subsequent patch this is a > > > problem in OOM situations because it relies on > > > pagefault_out_of_memory() being called even when the task has been > > > killed, to perform proper per-task OOM state unwinding. > > > > > > Shortcutting the fault like this is a rather minor optimization that > > > saves a few instructions in rare cases. Just remove it for > > > user-triggered faults. > > > > OK, I thought that this optimization tries to prevent calling OOM > > because the current might release some memory but that wasn't the > > intention of b80ef10e8 (x86: Move do_page_fault()'s error path under > > unlikely()). > > out_of_memory() also checks the caller for pending signals, so it > would not actually invoke the OOM killer if the caller is already > dying. Ohh, right you are! I should have checked deeper in the call chain. > > > Use the opportunity to split the fault retry handling from actual > > > fault errors and add locking documentation that reads suprisingly > > > similar to ARM's. > > > > > > Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> > > > > Reviewed-by: Michal Hocko <mhocko@xxxxxxx> > > Thanks! -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
