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From: Suresh Siddha <suresh.b.siddha@intel.com>
To: mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com,
	trenn@novell.com, prarit@redhat.com, tj@kernel.org
Cc: linux-kernel@vger.kernel.org, suresh.b.siddha@intel.com,
	youquan.song@intel.com
Subject: [patch v2 0/2] enhance stop machine infrastructure for MTRR rendezvous sequence
Date: Tue, 07 Jun 2011 13:14:11 -0700	[thread overview]
Message-ID: <20110607201411.791585562@sbsiddha-MOBL3.sc.intel.com> (raw)

First patch enhance the stop machine infrastructure so that we
can call __stop_machine() from the cpu hotplug path, where the calling
cpu is not yet online. We do allow this for already for !CONFIG_SMP. So this
patch brings the CONFIG_SMP behavior inline with !CONFIG_SMP

Second patch uses the enhanced __stop_machine() to implement the x86 MTRR
init rendezvous sequence and thus remove the duplicate implementation
of stop machine using stop_one_cpu_nowait(). This duplicate implementation
of stop machine can potentially lead to deadlock if there is a parallel
system wide rendezvous using __stop_machine().

Both these address one of the deadlocks mentioned in the
https://bugzilla.novell.com/show_bug.cgi?id=672008

Changes from v1:
* Use stop_cpu thread enabled status to find out if the cpu is online/offline,
  instead of using cpu_online(smp_processor_id()). This avoids a false
  positive of using smp_processor_id() from preemptible section.

thanks,
suresh


             reply	other threads:[~2011-06-07 20:16 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-07 20:14 Suresh Siddha [this message]
2011-06-07 20:14 ` [patch v2 1/2] stop_machine: enable __stop_machine() to be called from the cpu online path Suresh Siddha
2011-06-08 19:20   ` Ingo Molnar
2011-06-09  9:54   ` Tejun Heo
2011-06-09 22:50     ` Suresh Siddha
2011-06-07 20:14 ` [patch v2 2/2] x86, mtrr: use __stop_machine() for doing MTRR rendezvous Suresh Siddha

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