Re: [PATCH] remove name length check in a workqueue

[Frederic TEMPORELLI - astek]

James Bottomley a écrit :

> Well, but the other alternative is that we hit arbitrary BUG_ON() limits
> in systems that create numbered workqueues which is rather contrary to
> our scaleability objectives, isn't it?
>
> I think I'd rather the name truncation than have to respond to kernel
> BUG()'s.  If someone really has a problem with the appearance of ps,
> they can always increase TASK_COMM_LEN.
>
>  
>
> > We could truncate the name before adding the CPU number, but it sounds
> > saner to just prevent anyone passing in excessively long names.  Via
> > BUG_ON, say ;)
> >
> > What's the actual problem?
> >    
>
> What I posted originally; the current SCSI format for a workqueue:
> scsi_wq_%d hits the bug after the host number rises to 100, which has
> been seen by some enterprise person with > 100 HBAs.
>
> The reason for this name is that the error handler thread is called
> scsi_eh_%d; so we could rename all our threads to avoid this, but one
> day someone will come along with a huge enough machine to hit whatever
> limit we squeeze it down to.
>
> James
>
>  
In scsi layer (drivers/scsi/hosts.c), wq name length is limited to 
KOBJ_NAME_LEN due to the snprintf .
may be nice to use same limit if BUG_ON is kept... but why NULL isn't 
returned, then ?  ;-)

--
Tempo
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