linux-kernel - [PATCH v2 0/2] bitmap_parselist: support 'all' semantics

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Message-Id: <20210421031326.72816-1-yury.norov@gmail.com>
Date:   Tue, 20 Apr 2021 20:13:24 -0700
From:   Yury Norov <yury.norov@...il.com>
To:     linux-kernel@...r.kernel.org, rcu@...r.kernel.org,
        linux-doc@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Paul E. McKenney" <paulmck@...nel.org>
Cc:     Yury Norov <yury.norov@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Joel Fernandes <joel@...lfernandes.org>,
        Jonathan Corbet <corbet@....net>,
        Lai Jiangshan <jiangshanlai@...il.com>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Palmer Dabbelt <palmerdabbelt@...gle.com>,
        Paul Gortmaker <paul.gortmaker@...driver.com>,
        Randy Dunlap <rdunlap@...radead.org>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Steven Rostedt <rostedt@...dmis.org>
Subject: [PATCH v2 0/2] bitmap_parselist: support 'all' semantics

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.

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