On Mon, Apr 02, 2007 at 08:16:12AM +0200, Ingo Molnar wrote: > > i'm wondering about how TASK_UNINTERRUPTIBLE tasks are handled by the > freezer: are they assumed frozen immediately, or do we wait until they > notice their PF_FREEZING and go into try_to_freeze()? I'd expect > TASK_UNINTERRUPTIBLE to be the largest source of latency. (and hence be > the primary source for freezing 'failures')
Ok, we might be in some luck. I panic()ed on freezer fail and checked the stacktrace of the unfrozen tasks. The stacktrace of each one looks like: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PID: 7697 TASK: cc354a70 CPU: 7 COMMAND: "make" #0 [cc37fe50] schedule at c0431752 #1 [cc37fec4] wait_for_completion at c04318d0 #2 [cc37ff24] do_fork at c01249a6 #3 [cc37ff94] sys_vfork at c0103c1f #4 [cc37ffb4] system_call at c0104d8d ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Rafael had sent out a patch to fix the vfork race, which can be found at http://lkml.org/lkml/2007/3/1/212 However, the hunk @@ -1393,7 +1394,9 @@ long do_fork(unsigned long clone_flags, tracehook_report_clone_complete(clone_flags, nr, p); if (clone_flags & CLONE_VFORK) { + freezer_do_not_count(); wait_for_completion(&vfork); + freezer_count(); tracehook_report_vfork_done(p, nr); } } else { Seems to be missing in the latest -mm's. Rafael / Andrew, Any reasons for leaving this hunk out? I will rerun my tests with this hunk applied and report back. > > Ingo Thanks and Regards gautham. -- Gautham R Shenoy Linux Technology Center IBM India. "Freedom comes with a price tag of responsibility, which is still a bargain, because Freedom is priceless!" - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
