Userspace RCU 0.12.4 and 0.13.2 [LWN.net]

From:		Mathieu Desnoyers <mathieu.desnoyers-AT-efficios.com>
To:		linux-kernel <linux-kernel-AT-vger.kernel.org>, lttng-dev <lttng-dev-AT-lists.lttng.org>, rp <rp-AT-svcs.cs.pdx.edu>
Subject:		[RELEASE] Userspace RCU 0.12.4 and 0.13.2
Date:		Thu, 18 Aug 2022 16:07:34 -0400
Message-ID:		<1089391319.15796.1660853254177.JavaMail.zimbra@efficios.com>
Cc:		paulmck <paulmck-AT-kernel.org>, Stephen Hemminger <stephen-AT-networkplumber.org>, Alan Stern <stern-AT-rowland.harvard.edu>, Lai Jiangshan <jiangshanlai-AT-gmail.com>, lwn <lwn-AT-lwn.net>
Archive-link:		Article

[ re-sending without html headers. My email client managed to add those without me realizing it. ]

Hi,

This is stable release announcement for the Userspace RCU project.
It covers the two currently maintained stable branches: 0.12 and 0.13,
respectively with releases v0.12.4 and v0.13.2.

Especially for the spurious futex wakeup fix, users of the 0.12 and 0.13 (or older)
liburcu branches are recommended to upgrade.

* Noteworthy in these releases:

- Handle spurious futex wakeups in urcu-qsbr, urcu, urcu-wait, defer_rcu, call_rcu,
  and workqueue code. This has been known to cause issues where the workqueue
  worker thread spuriously takes nearly 100% of CPU time.

- Change method used by _rcu_dereference ot strip type constness.
  Rather than using pointer arithmetic (which does not work with opaque types),
  rely on a statement expression trick.

- Fix support for Linux systems where sysconf(_SC_NPROCESSORS_CONF) can
  return a value less than max cpu id.

Project website: https://liburcu.org

Feedback is welcome!

Thanks,

Mathieu

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com