Re: [PATCH v9 3/7] srcu: Fix invoke_rcu_callbacks() segcb length adjustment

Paul E. McKenney
2020-11-03T15:18:09Z

On Tue, Nov 03, 2020 at 10:07:38AM -0500, Joel Fernandes wrote:
> On Tue, Nov 03, 2020 at 03:47:14PM +0100, Frederic Weisbecker wrote:
> > On Tue, Nov 03, 2020 at 09:25:59AM -0500, Joel Fernandes (Google) wrote:
> > > With earlier patches, the negative counting of the unsegmented list
> > > cannot be used to adjust the segmented one. To fix this, sample the
> > > unsegmented length in advance, and use it after CB execution to adjust
> > > the segmented list's length.
> > >
> > > Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
> > > Suggested-by: Frederic Weisbecker <frederic@kernel.org>
> > > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> >
> > This breaks bisection, you need to either fix up the previous patch
> > by adding this diff inside or better yet: expand what you did
> > in "rcu/tree: Make rcu_do_batch count how many callbacks were executed"
> > to also handle srcu before introducing the segcb count.
>
> Since doing the latter is a lot more tedious and I want to get reviewing
> other's RCU patches today :) , I just squashed the suggestion into the
> counters patch to fix bissection:
> https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git/commit/?h=rcu/segcb-counts&id=595e3a65eeef109cb8fcbfcc114fd3ea2064b873
>
> Hope that's Ok. Also, so that I don't have to resend everything, here is the
> final branch if Paul wants to take it:
> git://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git (branch rcu/segcb-counts)

Either way, it sounds like it is time for me to review this series.

Thank you both very much!!!

Thaxn, Paul