linux-kernel - Re: [rfc patch] hotplug: Call mmdrop_delayed() in sched_cpu_dying() if PREEMPT_RT

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] [day] [month] [year] [list]

Message-ID: <20161020112145.tyz6pcoimysha3jz@linutronix.de>
Date:   Thu, 20 Oct 2016 13:21:45 +0200
From:   Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:     Mike Galbraith <umgwanakikbuti@...il.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-rt-users <linux-rt-users@...r.kernel.org>,
        Steven Rostedt <rostedt@...dmis.org>
Subject: Re: [rfc patch] hotplug: Call mmdrop_delayed() in sched_cpu_dying()
 if PREEMPT_RT_FULL

On 2016-10-20 11:34:03 [+0200], Mike Galbraith wrote:
> My 64 core box just passed an hour running Steven's hotplug stress
> script along with stockfish and futextests (tip-rt.today w. hotplug
> hacks you saw a while back), and seems content to just keep on grinding
> away.  Without it, box quickly becomes a doorstop.

This is new. It is v4.7-rc1 new. The hotplug rework moved the notified
around and after

e9cd8fa4fcfd ("sched/migration: Move calc_load_migrate() into CPU_DYING")
f2785ddb5367 ("sched/hotplug: Move migration CPU_DYING to sched_cpu_dying()")

we have no more CPU_DEAD, just CPU_DYING which is invoked with
interrupts off. I don't see anything wrong with pushing this over to
RCU.

Sebastian