On Fri, 5 Jun 2015 18:10:21 +0200 Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Fri, Jun 05, 2015 at 05:01:08PM +0200, Petr Mladek wrote: > > Many kthreads go into an interruptible sleep when there is nothing > > to do. They should check if anyone did not requested the kthread > > to terminate, freeze, or park in the meantime. It is easy to do > > it a wrong way. > > INTERRUPTIBLE is the wrong state to idle in for kthreads, use > TASK_IDLE. > > --- > > commit 80ed87c8a9ca0cad7ca66cf3bbdfb17559a66dcf > Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Date: Fri May 8 14:23:45 2015 +0200 > > sched/wait: Introduce TASK_NOLOAD and TASK_IDLE > > Currently people use TASK_INTERRUPTIBLE to idle kthreads and wait for > 'work' because TASK_UNINTERRUPTIBLE contributes to the loadavg. Having > all idle kthreads contribute to the loadavg is somewhat silly. Not to mention, tasks in TASK_UNINTERRUPTIBLE state for too long will trigger hung task detection. > > Now mostly this works OK, because kthreads have all their signals > masked. However there's a few sites where this is causing problems and > TASK_UNINTERRUPTIBLE should be used, except for that loadavg issue. > > This patch adds TASK_NOLOAD which, when combined with > TASK_UNINTERRUPTIBLE avoids the loadavg accounting. > > As most of imagined usage sites are loops where a thread wants to > idle, waiting for work, a helper TASK_IDLE is introduced. > > Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx> -- Steve > Cc: Julian Anastasov <ja@xxxxxx> > Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Cc: NeilBrown <neilb@xxxxxxx> > Cc: Oleg Nesterov <oleg@xxxxxxxxxx> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> > > diff --git a/include/linux/sched.h b/include/linux/sched.h -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
