Re: [PATCH v2 0/2] bitmap_parselist: support 'all' semantics

From: Yury Norov
Date: Wed Apr 21 2021 - 13:49:57 EST


On Wed, Apr 21, 2021 at 10:30:08AM -0700, Paul E. McKenney wrote:
> On Tue, Apr 20, 2021 at 08:13:24PM -0700, Yury Norov wrote:
> > RCU code supports a special group 'all' which selects all bits in a bitmap.
> > We have recently added 'N' extension for bitmap parse, so that '0-N' would
> > have exactly the same meaning as 'all'. But because the 'all' is already
> > used by RCU, it would be reasonable to support it in core bitmap code as a
> > common and easy-readable alias for '0-N'.
> >
> > Moving the 'all' support to core bitmap code adds another level of
> > flexibility for system configuration by supporting patterns. For example,
> > every second bit in cpumask may be selected like this:
> > isolcpus=all:1/2
> >
> > v2:
> > - cleanup patch 1;
> > - in patch 2 explain why dropping legacy comment.
>
> Nice!
>
> I have pulled this into -rcu with some minor updates, including replacing
> the "isolcpus=all" with "rcu_nocbs=all:1/2" per Steve Rostedt's feedback.

Thank you Paul and Steven for fixing this 'isolcpus=all'.
'rcu_nocbs=all:1/2' would look better in the documentation.

> Could you please check to make sure that I didn't mess anything up?

Everything is OK. Thank you for fixing this.

> If tests go well, this will go into -next later today or tomorrow.
> Although I cannot prove that this will not make the upcoming merge window,
> but Murphy insists that it will instead be the v5.14 merge window.
>
> Thanx, Paul
>
> > Yury Norov (2):
> > bitmap_parse: support 'all' semantics
> > rcu/tree_plugin: don't handle the case of 'all' CPU range
> >
> > Documentation/admin-guide/kernel-parameters.rst | 5 +++++
> > kernel/rcu/tree_plugin.h | 9 +++------
> > lib/bitmap.c | 9 +++++++++
> > lib/test_bitmap.c | 7 +++++++
> > 4 files changed, 24 insertions(+), 6 deletions(-)
> >
> > --
> > 2.25.1
> >