On 08/24/2018 01:41 PM, Frederic Weisbecker wrote: > On Fri, Aug 24, 2018 at 11:10:44AM -0500, Grygorii Strashko wrote: >> Yes. i do not see local_softirq_pending messages any more >> >> But one question, just to clarify, after patch "nohz: Fix missing tick reprog while interrupting inline timer softirq" >> the tick_nohz_irq_exit() will be called few times in case of nested interrupts (min 2): >> gic_handle_irq >> |- irq_exit >> |- preempt_count_sub(HARDIRQ_OFFSET); >> |-__do_softirq >> <irqs enabled> >> |- gic_handle_irq() >> |- irq_exit() >> |- tick_irq_exit() >> if (!in_irq()) >> tick_nohz_irq_exit(); <-- [1] >> |- tick_irq_exit() >> if (!in_irq()) >> tick_nohz_irq_exit(); <-- [2] >> >> Is it correct? in 4.14 tick_nohz_irq_exit() is much more complex then in LKML now, >> and this is hot path. > > That's correct and it's indeed more costly in 4.14 as then the tick is going to be programmed > twice. > Sry, that disturbing you all, but what are the conclusion here for 4.14.y? - take Thomas's patch https://lore.kernel.org/patchwork/patch/969521/#1162900 - revert commit 2d898915ccf4838c04531c51a598469e921a5eb5 -- regards, -grygorii
