linux-kernel - [RELEASE] Userspace RCU 0.12.0

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <605758779.29080.1586458795931.JavaMail.zimbra@efficios.com>
Date:   Thu, 9 Apr 2020 14:59:55 -0400 (EDT)
From:   Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
To:     linux-kernel@...r.kernel.org, lttng-dev@...ts.lttng.org,
        rp@...s.cs.pdx.edu
Cc:     "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
        Stephen Hemminger <stephen@...workplumber.org>,
        Alan Stern <stern@...land.harvard.edu>,
        Lai Jiangshan <jiangshanlai@...il.com>, lwn@....net,
        Alex Xu <alex_y_xu@...oo.ca>
Subject: [RELEASE] Userspace RCU 0.12.0

Hi,

This announcement introduces the 0.12 version of liburcu.

liburcu is a LGPLv2.1 userspace RCU (read-copy-update) library. This
data synchronization library provides read-side access which scales
linearly with the number of cores. It does so by allowing multiple
copies of a given data structure to live at the same time, and by
monitoring the data structure accesses to detect grace periods after
which memory reclamation is possible.

liburcu-cds provides efficient data structures based on RCU and
lock-free algorithms. Those structures include hash tables, queues,
stacks, and doubly-linked lists.

* New in this release:

This 0.12 liburcu release is mainly done to add a DEFINE_URCU_TLS_INIT
macro to the urcu/tls-compat.h API. There is a very recent unfortunate
situation where a major user of liburcu (lttng-ust 2.12) added a use
of DEFINE_URCU_TLS such as:

  DEFINE_URCU_TLS(ino_t, cached_net_ns) = NS_INO_UNINITIALIZED;

Which builds and runs fine for CONFIG_RCU_TLS, but fails to build for
!CONFIG_RCU_TLS. Fixing this required to extend the API and add a new
DEFINE_URCU_TLS_INIT() which could then be used in this way:

  DEFINE_URCU_TLS_INIT(ino_t, cached_net_ns, NS_INO_UNINITIALIZED);

Support for FreeBSD and DragonFlyBSD is also added in this release,
contributed by Alex Xu. It uses _mutx_op() to implement the liburcu
futex APIs on FreeBSD.

Finally, a noteworthy change has been done to the urcu-bp flavor:
urcu_bp_register_thread() now performs the underlying lazy registration
of the caller thread rather than being a pure no-op. This is useful
for some real-time use-cases (e.g. Xenomai) which require to perform
urcu-bp thread registration early in the thread life-time before it
starts performing real-time tasks.

Thanks,

Mathieu

Project website: http://liburcu.org
Git repository: git://git.liburcu.org/urcu.git

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