| Date | Thu, 6 Sep 2012 10:32:07 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH tip/core/rcu 06/23] rcu: Break up rcu_gp_kthread() into subfunctions |
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On Thu, Sep 06, 2012 at 03:39:51PM +0200, Peter Zijlstra wrote: > On Thu, 2012-08-30 at 11:18 -0700, Paul E. McKenney wrote: > > +static int rcu_gp_kthread(void *arg) > > +{ > > + struct rcu_state *rsp = arg; > > + struct rcu_node *rnp = rcu_get_root(rsp); > > + > > + for (;;) { > > + > > + /* Handle grace-period start. */ > > + for (;;) { > > + wait_event_interruptible(rsp->gp_wq, rsp->gp_flags); > > + if (rsp->gp_flags && rcu_gp_init(rsp)) > > + break; > > + cond_resched(); > > + flush_signals(current); > > + } > > > > /* Handle grace-period end. */ > > for (;;) { > > wait_event_interruptible(rsp->gp_wq, > > !ACCESS_ONCE(rnp->qsmask) && > > !rcu_preempt_blocked_readers_cgp(rnp)); > > if (!ACCESS_ONCE(rnp->qsmask) && > > + !rcu_preempt_blocked_readers_cgp(rnp) && > > + rcu_gp_cleanup(rsp)) > > break; > > + cond_resched(); > > flush_signals(current); > > } > > } > > return 0; > > } > > Should there not be a kthread_stop() / kthread_park() call somewhere in > there?
The kthread stops only when the system goes down, so no need for any kthread_stop() or kthread_park(). The "return 0" suppresses complaints about falling of the end of a non-void function.
> Also, it could be me, but all those nested for (;;) loops make the flow > rather non-obvious.
For those two loops, I suppose I could pull the cond_resched() and flush_signals() to the top, and make a do-while out of it.
Thanx, Paul
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