linux-kernel - [PATCH RFC tip/core/rcu 0/2] Real-time elimination of RCU

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-Id: <20190329182608.GA23877@linux.ibm.com>
Date:   Fri, 29 Mar 2019 11:26:08 -0700
From:   "Paul E. McKenney" <paulmck@...ux.ibm.com>
To:     rcu@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, mingo@...nel.org,
        jiangshanlai@...il.com, dipankar@...ibm.com,
        akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
        josh@...htriplett.org, tglx@...utronix.de, peterz@...radead.org,
        rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com,
        fweisbec@...il.com, oleg@...hat.com, joel@...lfernandes.org,
        bigeasy@...utronix.de
Subject: [PATCH RFC tip/core/rcu 0/2] Real-time elimination of RCU_SOFTIRQ

Hello!

This series is an early posting of code to add a boot-time option to
move RCU's softirq processing to per-CPU kthreads.  This is not done
by default for performance reasons, nor are these reasons theoretical.
In fact, earlier attempts to do just this were not met with silence.

The patches are as follows:

1.	Enable elimination of Tree-RCU softirq processing via a new
	rcutree.use_softirq kernel boot parameter.  This defaults to 1,
	so boot with "rcutree.use_softirq=0" to move RCU_SOFTIRQ work
	to the rcuc kthreads.  Courtesy of Sebastian Andrzej Siewior.

2.	Improve wakeup-safety checks in rcu_read_unlock_special(),
	thus allowing both rcuc kthreads and reasonably snappy
	expedited RCU grace periods.

							Thanx, Paul

------------------------------------------------------------------------

 Documentation/admin-guide/kernel-parameters.txt |    6 
 include/linux/sched.h                           |    2 
 kernel/rcu/tree.c                               |  138 +++++++++++++++++++--
 kernel/rcu/tree.h                               |    2 
 kernel/rcu/tree_plugin.h                        |  153 ++++--------------------
 5 files changed, 161 insertions(+), 140 deletions(-)