Messages in this thread | | | Date | Tue, 7 Oct 2014 20:24:11 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH v2 1/2] workqueue: add quiescent state between work items |
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On Tue, Oct 07, 2014 at 01:45:28PM -0400, Joe Lawrence wrote: > On Tue, 7 Oct 2014 06:43:29 -0700 > "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote: > > > On Tue, Oct 07, 2014 at 09:29:42AM +0200, Jiri Pirko wrote: > [ ... snip ... ] > > > > > > Paul, Tehun, how do you propose to fix this on older kernels which do > > > not have rcu_note_voluntary_context_switch? I'm particullary interested > > > in 3.10. > > > > Hello, Jiri, > > > > Older kernels can instead use rcu_note_context_switch(). > > Hi Paul, > > Does 4a81e8328d37 ("rcu: Reduce overhead of cond_resched() checks for > RCU") affect a backport to 3.10? > > I noticed that rcu_note_context_switch added a call to > rcu_momentary_dyntick_idle in that change, which is only present in > v3.16+. > > Would rcu_note_context_switch be effective by itself on a 3.10 kernel?
Should be fine. There is more overhead than current mainline, but that should not be in the noise compared to executing a work-queue item.
Thanx, Paul
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