On Thu, 8 Mar 2012 14:08:30 -0800 (PST) David Rientjes <rientjes@xxxxxxxxxx> wrote: > On Thu, 8 Mar 2012, Andrew Morton wrote: > > > > We have a get_task_comm() that does the task_lock() > > > internally but requires a TASK_COMM_LEN buffer in the calling code. It's > > > just easier for the calling code to the task_lock() itself for a tiny > > > little printk(). > > > > Well for a tiny little printk we could just omit the locking? The > > printk() won't oops and once in a million years one person will see a > > garbled comm[] string? > > > > Sure, but task_lock() shouldn't be highly contended when the thread isn't > forking or exiting (everything else is attaching/detaching from a cgroup > or testing a mempolicy). I've always added it (like in the oom killer for > the same reason) just because the race exists. Taking it for every thread > on the system for one call to the oom killer has never slowed it down. I wasn't concerned about the performance side of things - just that it's such a pain over such a silly thing. btw, if the code had done printk_once(..., get_task_comm(...), ...) the task_lock() would have been performed just a single time, rather than every time. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>