Messages in this thread | | | Date | Tue, 29 Oct 2013 20:10:16 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH 1/1] hung_task debugging: Add tracepoint to report the hang |
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On 10/20, Ingo Molnar wrote: > > * Oleg Nesterov <oleg@redhat.com> wrote: > > > Currently check_hung_task() prints a warning if it detects the problem, > > but it is not convenient to watch the system logs if user-space wants to > > be notified about the hang. > > > > Add the new trace_sched_process_hang() into check_hung_task(), this way > > a user-space monitor can easily wait for the hang and potentially > > resolve a problem. > > I'm wondering, is the data of trace_console() in kernel/printk/printk.c > not sufficient?
Probably yes... I do not think they disable CONFIG_PRINTK.
But this is obviously much less convenient, they will need to parse the text. And the user-space watchdog will be woken up much more often than necessary. And they could probably simply read /var/log or interact with syslogd somehow, but they specially asked for something better and more robust.
But of course, I understand that every tracepoint should be justified. So if you do not like this change I try to convince them to use trace_console().
> If it's not enough then it might be better to add a higher level printk > tracepoint instead - that can catch hung_task messages and (much) more.
Not sure I understand... I mean I do not understand why this is really better for them, except this will simplify the parsing a bit. Anyway I'd prefer to not send another doubtful patch ;)
Thanks.
Oleg.
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