[sheepdog] `tid_max` in lib/work.c need to be initialized

[Hitoshi Mitake]

At Tue, 28 Oct 2014 17:52:04 +0800,
Jinzhi Chen wrote:
> 
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> sorry, i'thinks `tid_max` should be set to 1,

Hi Jinzhi,

Thanks for your report. It seems to be reasonable. Current tracing
subsystem has a problem as you say. tid_max should be set to 1 and
tid_map should have bitmap area for it as soon as possible in the
initialization process of sheep. In addition, sd_thread_create() must
update tid_max.

Seems that you understand the problem well, could you prepare a patch
for it if you have time? Or could you add an issue to our launchpad
bugtracker?

Thanks,
Hitoshi

> 
> On Tue, Oct 28, 2014 at 5:29 PM, Jinzhi Chen <nxtjinzhi at gmail.com> wrote:
> 
> > hi,
> >
> > I'm currently using sheepodg v0.8.3, configure with --enable-debug & start
> > sheep with journal directory.
> >
> >
> > during `journal_file_init` progress, journal thread is created.
> > but the `tid_max` is not initialized until `wq_trace_init` is called,
> > which is called just after journal init progress.
> > Thus the journal thread enter into infinite loop when trace is enabled.
> > (below is related code)
> >
> >
> > static void trace_set_tid_map(int tid)
> > {
> >         sd_mutex_lock(&tid_map_lock);
> >         if (tid > tid_max) {
> >                 size_t old_tid_max = tid_max;
> >
> >                 /* enlarge bitmap size */
> >                 ## because tid_max is not initialized (which is 0), the
> > journal thread enter into loop
> >                 while (tid > tid_max)
> >                         tid_max *= 2;
> >
> >                 tid_map = alloc_bitmap(tid_map, old_tid_max, tid_max);
> >         }
> >         set_bit(tid, tid_map);
> >         sd_mutex_unlock(&tid_map_lock);
> > }
> >
> > I think `tid_max` should be initialized to TID_MAX_DEFAULT in to avoid
> > issue.
> > thus, change lib/work.c
> >
> > -static size_t tid_max;
> > +static size_t tid_max = TID_MAX_DEFAULT
> >
> > & delete related code in wq_trace_init
> >
> > Correct me if I'm wrong.
> >
> >
> > Thanks
> >
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