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-prev] [thread-next>] [day] [month] [year] [list]
Date:   Tue, 21 Nov 2023 08:46:28 -0800
From:   "Paul E. McKenney" <>
To:     Peter Zijlstra <>
Cc:     Mathieu Desnoyers <>,
        Steven Rostedt <>,
        Masami Hiramatsu <>,,
        Michael Jeanson <>,
        Alexei Starovoitov <>,
        Yonghong Song <>, Ingo Molnar <>,
        Arnaldo Carvalho de Melo <>,
        Mark Rutland <>,
        Alexander Shishkin <>,
        Jiri Olsa <>,
        Namhyung Kim <>,,
        Joel Fernandes <>
Subject: Re: [PATCH v4 1/5] tracing: Introduce faultable tracepoints

On Tue, Nov 21, 2023 at 05:03:00PM +0100, Peter Zijlstra wrote:
> On Tue, Nov 21, 2023 at 07:58:40AM -0800, Paul E. McKenney wrote:
> > Tasks Trace RCU allows general blocking in its readers, not just the
> > subject-to-priority-boosting blocking permitted within preemptible RCU
> > readers.  Restrictions on the use of Tasks Trace RCU are in place to allow
> > getting away with this general blocking.  Even systems generously endowed
> > with memory are not going to do well when the RCU grace period is blocked
> > on I/O, especially if that I/O is across a network to a slow file server.
> > 
> > Which means a separate RCU instance is needed.  Which is Tasks Trace RCU.
> Separate instance not a problem, nor really the question.
> What is the basic mechanism of task-tracing? Is it really the existing
> tasks-rcu extended with read-side critical sections and call_rcu ?
> If so, then why not have it be tasks-rcu?
> Or is it a variant of the preemptible/SRCU class of RCUs that are
> counter-array based? I suspect not.
> So once again, what exactly is tasks-tracing ?

I think we covered this elsewhere in the thread, but if there are
lingering questions, you know where to find us.  ;-)

							Thanx, Paul

Powered by blists - more mailing lists