From: Borislav Petkov <bp@alien8.de>
To: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
LKML <linux-kernel@vger.kernel.org>, Borislav Petkov <bp@suse.de>,
Ingo Molnar <mingo@kernel.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
"ego@linux.vnet.ibm.com" <ego@linux.vnet.ibm.com>,
Oleg Nesterov <oleg@redhat.com>
Subject: Re: [PATCH] intel_rapl: Correct hotplug correction
Date: Thu, 22 May 2014 14:13:28 +0200 [thread overview]
Message-ID: <20140522121328.GI4383@pd.tnic> (raw)
In-Reply-To: <537DE579.6000505@linux.vnet.ibm.com>
On Thu, May 22, 2014 at 05:24:33PM +0530, Srivatsa S. Bhat wrote:
> That was just me trying to explain the current mess, not justifying
> it! :-/
Yes, it is a mess - thanks for explaining it.
> I think Oleg had a proposed patch to use per-cpu rwsem in CPU hotplug to
> drastically simplify this whole locking scheme. I think we could look at
> that again.
And that is my question: why can't all be made to use a single dumb lock
allowing only one task and lock everything hotplug with it?
Maybe it is an oversimplification but why do I care about hotplug
operations scaling - they're not on the fastpath anyway.
And yes, we're trying to remove CPU_POST_DEAD - I have one user in
MCE which I'm testing a removal patch for - and then we can all use
get_/put_online_cpus() like we used to do and be happy.
Having 2 + 1 aliased hotplug sync APIs is beyond insane and is simply
not needed IMHO.
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
--
next prev parent reply other threads:[~2014-05-22 12:13 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-22 9:23 [PATCH] intel_rapl: Correct hotplug correction Borislav Petkov
2014-05-22 9:43 ` Srivatsa S. Bhat
2014-05-22 10:08 ` Borislav Petkov
2014-05-22 11:54 ` Srivatsa S. Bhat
2014-05-22 12:13 ` Borislav Petkov [this message]
2014-05-22 12:32 ` Peter Zijlstra
2014-05-22 15:30 ` [PATCH] x86, MCE: Kill CPU_POST_DEAD Borislav Petkov
2014-05-22 15:50 ` Luck, Tony
2014-05-22 19:55 ` Borislav Petkov
2014-05-22 21:13 ` Srivatsa S. Bhat
2014-05-22 21:31 ` Borislav Petkov
2014-05-22 21:40 ` Srivatsa S. Bhat
2014-05-22 21:43 ` Srivatsa S. Bhat
2014-05-26 20:01 ` Borislav Petkov
2014-05-22 21:31 ` [PATCH] intel_rapl: Correct hotplug correction Srivatsa S. Bhat
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