linux-kernel - Re: [PATCH tip/core/rcu 13/22] rcu: Fix grace-period hangs due to race with CPU offline

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

Message-ID: <20180626194807.GQ2494@hirez.programming.kicks-ass.net>
Date:   Tue, 26 Jun 2018 21:48:07 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
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, rostedt@...dmis.org,
        dhowells@...hat.com, edumazet@...gle.com, fweisbec@...il.com,
        oleg@...hat.com, joel@...lfernandes.org
Subject: Re: [PATCH tip/core/rcu 13/22] rcu: Fix grace-period hangs due to
 race with CPU offline

On Tue, Jun 26, 2018 at 11:19:37AM -0700, Paul E. McKenney wrote:
> The initial reason for ____cacheline_internodealigned_in_smp was that
> some of the fields can be accessed by random CPUs, while others are
> used more locally, give or take our usual contention over the handling
> of CPU numbers.  ;-)

So that whole internode thing only matters for the insane VSMP case,
where they take node to mean a cluster node, not a numa node.

VSMP is a networked shared memory machine where, by necessity, the MESI
protocol operates on page granularity.

In general I tend to completely and utterly ignore that and let the VSMP
people worry about things.