lkml.org 
[lkml]   [2022]   [May]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 03/21] rcu: Add a note about noinstr VS unsafe eqs functions
On Thu, May 19, 2022 at 08:26:11AM -0700, Paul E. McKenney wrote:
> On Thu, May 19, 2022 at 04:54:38PM +0200, Peter Zijlstra wrote:
> > On Tue, May 03, 2022 at 12:00:33PM +0200, Frederic Weisbecker wrote:
> > > Some RCU functions enter or exit into/from RCU idle mode while using
> > > trace-able and lockdep-aware IRQs (un-)masking. This could be easily
> > > solved with using raw versions of local_irq_*() but we would then
> > > lose some precious debugging informations.
> > >
> > > Another possible way to solve this may consist in using rude RCU-tasks
> > > in lockdep and irqsoff tracing.
> > >
> > > In any case and until this get solved, those RCU functions can't get
> > > tagged as noinstr even though they should.
> >
> > FWIW, this also means RCU_NONIDLE() is broken. Luckily there aren't many
> > users left.
>
> More to the point, rcu_irq_enter_irqson() and rcu_irq_exit_irqson() need
> the same help that rcu_idle_enter() and rcu_idle_exit() got earlier this
> week [1], independent of RCU_NONIDLE().
>
> Unless Frederic beats me to it, I will queue something up.

It's in the patchset I just posted (02/21).

>
> Thanx, Paul
>
> [1] https://lore.kernel.org/all/20220518162118.GA2661055@paulmck-ThinkPad-P17-Gen-1/

\
 
 \ /
  Last update: 2022-05-19 17:37    [W:0.106 / U:0.044 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site