Messages in this thread | | | Date | Tue, 27 Jun 2023 00:59:03 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH v3] sched/isolation: add a workqueue parameter onto isolcpus to constrain unbound CPUs |
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On Thu, Jun 22, 2023 at 11:22:17AM +0800, tiozhang wrote: > Motivation of doing this is to better improve boot times for devices when > we want to prevent our workqueue works from running on some specific CPUs, > i,e, some CPUs are busy with interrupts. > > Also remove HK_FLAG_WQ from nohz_full to prevent nohz_full overriding > workqueue's cpu config.
But then nohz_full= doesn't re-affine workqueues anymore, right?
> > Suggested-by: Tejun Heo <tj@kernel.org> > Signed-off-by: tiozhang <tiozhang@didiglobal.com> > --- > kernel/sched/isolation.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c > index 373d42c707bc..5cd67c51622e 100644 > --- a/kernel/sched/isolation.c > +++ b/kernel/sched/isolation.c > @@ -181,8 +181,8 @@ static int __init housekeeping_nohz_full_setup(char *str) > { > unsigned long flags; > > - flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU | > - HK_FLAG_MISC | HK_FLAG_KTHREAD; > + flags = HK_FLAG_TICK | HK_FLAG_TIMER | HK_FLAG_RCU | HK_FLAG_MISC > + | HK_FLAG_KTHREAD; > > return housekeeping_setup(str, flags); > } > @@ -208,6 +208,12 @@ static int __init housekeeping_isolcpus_setup(char *str) > continue; > } > > + if (!strncmp(str, "workqueue,", 10)) { > + str += 10; > + flags |= HK_FLAG_WQ; > + continue; > + } > +
I'm planning on removing HK_FLAG_TICK, HK_FLAG_WQ, HK_FLAG_TIMER, HK_FLAG_RCU, HK_FLAG_MISC and HK_FLAG_KTHREAD and merge them all together. Also the problem with these flags is that once they are modified on boot, you can't modify them later.
I much prefer what was done in this patch:
https://lore.kernel.org/all/20230623073033.GA6584@didi-ThinkCentre-M930t-N000/
Thanks!
> if (!strncmp(str, "managed_irq,", 12)) { > str += 12; > flags |= HK_FLAG_MANAGED_IRQ; > -- > 2.17.1 >
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