Messages in this thread | | | Date | Fri, 30 Jan 2009 12:41:02 -0800 | From | Mandeep Singh Baines <> | Subject | Re: [PATCH v4] softlockup: remove hung_task_check_count |
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Mandeep Singh Baines (msb@google.com) wrote: > Peter Zijlstra (peterz@infradead.org) wrote: > > > > Why break out at all? Are you that worried about khungtaskd introducing > > latencies? > > Yes, I was worried about disabling preemption for an unbounded amount of > time. > > > Is using preemptible RCU an option for you? > > > > I had not even considered that. To be honest, I had not even heard of it > till now. So I spent another morning at LWN grokking preemptible RCU;) > > I think it can work. I'm a little worried about the OOM risk. It could take > a really long time to iterate over the task list. A lot of pending kfree()s > could build up in that time. >
I misunderstood preemptible RCU. I assumed it was a new API but its not. So I don't think preemptible RCU is an option since it would force a dependency on CONFIG_PREEMPT_RCU.
I'm going to break up this patch in two. One patch for converting to rcu. A second patch which will support checking all tasks. To support checking all tasks I reverted back to a design similar to Frédéric original proposal.
I'll send the patches out right after this email.
[PATCH 1/2] softlockup: convert read_lock in hung_task to rcu_read_lock [PATCH 2/2] softlockup: check all tasks in hung_task
Regards, Mandeep -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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