linux-kernel - Re: [PATCH RFC tip/core/rcu 11/11] rcu: move TREE

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

Message-ID: <alpine.DEB.2.00.1102231317550.4823@router.home>
Date:	Wed, 23 Feb 2011 13:19:15 -0600 (CST)
From:	Christoph Lameter <cl@...ux.com>
To:	Steven Rostedt <rostedt@...dmis.org>
cc:	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>,
	Frederic Weisbecker <fweisbec@...il.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	linux-kernel@...r.kernel.org, mingo@...e.hu, laijs@...fujitsu.com,
	dipankar@...ibm.com, akpm@...ux-foundation.org,
	josh@...htriplett.org, niv@...ibm.com, tglx@...utronix.de,
	peterz@...radead.org, Valdis.Kletnieks@...edu, dhowells@...hat.com,
	eric.dumazet@...il.com, darren@...art.com,
	"Paul E. McKenney" <paul.mckenney@...aro.org>
Subject: Re: [PATCH RFC tip/core/rcu 11/11] rcu: move TREE_RCU from softirq
 to kthread

On Wed, 23 Feb 2011, Steven Rostedt wrote:

> On Wed, 2011-02-23 at 12:29 -0600, Christoph Lameter wrote:
>
> > Right if the kthread context can be rescheduled then either preemption
> > needs to be disabled to guarantee that all three access the same per cpu
> > area data or the code needs to be changed in such a way that a this_cpu
> > RMW instructions can do the mods in one go.
>
> Are you suggesting a this_cpu_atomic_inc()?

this_cpu_inc is already percpu atomic. On x86 it is an instruction that
cannot be interrupted nor preempted while in progress.

There is also this_cpu_cmpxchg() which could be used to do some more
advanced tricks.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/