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

From: Yury Norov <yury.norov@gmail.com>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: linux-kernel@vger.kernel.org, rcu@vger.kernel.org,
	linux-doc@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Joel Fernandes <joel@joelfernandes.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Palmer Dabbelt <palmerdabbelt@google.com>,
	Paul Gortmaker <paul.gortmaker@windriver.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH v2 0/2] bitmap_parselist: support 'all' semantics
Date: Wed, 21 Apr 2021 10:49:50 -0700	[thread overview]
Message-ID: <20210421174950.GA106553@yury-ThinkPad> (raw)
In-Reply-To: <20210421173008.GV975577@paulmck-ThinkPad-P17-Gen-1>

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
> > 