On Wed, May 23, 2012 at 5:03 PM, Jesse Gross <je...@nicira.com> wrote: > On Wed, May 23, 2012 at 10:36 AM, Pravin B Shelar <pshe...@nicira.com> wrote: >> OVS datapath does periodic flow table rehash which takes genl_lock >> in workq context. >> In some cases, like ports add or delete, genl_lock can cause softlockup >> as vswitchd would take and succeed with genl_lock and rehash workq >> would block on the lock. Eventually rehash will proceed, flow rehash >> is low priority task so this is not problem for rehashing. >> But it is blocking workq thread; some other workq item from other >> kernel subsystem would be blocked and can cause system freeze. >> To avoid workq blocking and system freeze, we can use OVS compat workq. >> It runs in separate kernel thread thus does not block any non-ovs >> deferred workq work item. >> >> Signed-off-by: Pravin B Shelar <pshe...@nicira.com> > > Can you add a note in the commit message about how we're planning on > addressing this in the future? > ok
> I got a whitespace error: > > Applying: datapath: Avoid system freeze due to ovs-flow-rehash softlockup. > /home/jesse/openvswitch/.git/rebase-apply/patch:64: new blank line at EOF. > + > warning: 1 line adds whitespace errors. > >> diff --git a/datapath/linux/compat/include/linux/workqueue.h >> b/datapath/linux/compat/include/linux/workqueue.h >> index 919afe3..e5e2178 100644 >> --- a/datapath/linux/compat/include/linux/workqueue.h >> +++ b/datapath/linux/compat/include/linux/workqueue.h >> @@ -68,6 +64,7 @@ int cancel_delayed_work_sync(struct delayed_work *dwork); >> (_work)->func = (_func); \ >> } while (0) >> >> -#endif /* kernel version < 2.6.23 */ >> + >> +extern void flush_scheduled_work(void); > > Is this declaration necessary? I didn't find any other references to it. In new kernel it is declared in workqueue.h and used in interrupt.h, thats why we just need declaration. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
