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From: Bharata B Rao <bharata@linux.vnet.ibm.com>
To: Dan Streetman <ddstreet@ieee.org>
Cc: Thomas Falcon <tlfalcon@linux.vnet.ibm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	linux-kernel@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
	Tyrel Datwyler <tyreld@linux.vnet.ibm.com>,
	Grant Likely <grant.likely@linaro.org>,
	Nathan Fontenot <nfont@linux.vnet.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Neil Zhang <zhangwm@marvell.com>,
	linuxppc-dev@lists.ozlabs.org, Daniel Walter <dwalter@google.com>
Subject: Re: [PATCH] powerpc: use device_online/offline() instead of cpu_up/down()
Date: Sun, 2 Nov 2014 10:28:51 +0530	[thread overview]
Message-ID: <20141102045851.GA8334@in.ibm.com> (raw)
In-Reply-To: <1414784494-12573-1-git-send-email-ddstreet@ieee.org>

On Fri, Oct 31, 2014 at 03:41:34PM -0400, Dan Streetman wrote:
> In powerpc pseries platform dlpar operations, Use device_online() and
> device_offline() instead of cpu_up() and cpu_down().
> 
> Calling cpu_up/down directly does not update the cpu device offline
> field, which is used to online/offline a cpu from sysfs.  Calling
> device_online/offline instead keeps the sysfs cpu online value correct.
> The hotplug lock, which is required to be held when calling
> device_online/offline, is already held when dlpar_online/offline_cpu
> are called, since they are called only from cpu_probe|release_store.
> 
> This patch fixes errors on PowerVM systems that have cpu(s) added/removed
> using dlpar operations; without this patch, the
> /sys/devices/system/cpu/cpuN/online nodes do not correctly show the
> online state of added/removed cpus.

Verified the patch to be working as expected when I online and offline
CPUs of a PowerKVM guest using QEMU (plus my RFC hotplug patchset for
QEMU)

Regards,
Bharata.

WARNING: multiple messages have this Message-ID (diff)
From: Bharata B Rao <bharata@linux.vnet.ibm.com>
To: Dan Streetman <ddstreet@ieee.org>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Tyrel Datwyler <tyreld@linux.vnet.ibm.com>,
	Paul Mackerras <paulus@samba.org>,
	Thomas Falcon <tlfalcon@linux.vnet.ibm.com>,
	Grant Likely <grant.likely@linaro.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Daniel Walter <dwalter@google.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Neil Zhang <zhangwm@marvell.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] powerpc: use device_online/offline() instead of cpu_up/down()
Date: Sun, 2 Nov 2014 10:28:51 +0530	[thread overview]
Message-ID: <20141102045851.GA8334@in.ibm.com> (raw)
In-Reply-To: <1414784494-12573-1-git-send-email-ddstreet@ieee.org>

On Fri, Oct 31, 2014 at 03:41:34PM -0400, Dan Streetman wrote:
> In powerpc pseries platform dlpar operations, Use device_online() and
> device_offline() instead of cpu_up() and cpu_down().
> 
> Calling cpu_up/down directly does not update the cpu device offline
> field, which is used to online/offline a cpu from sysfs.  Calling
> device_online/offline instead keeps the sysfs cpu online value correct.
> The hotplug lock, which is required to be held when calling
> device_online/offline, is already held when dlpar_online/offline_cpu
> are called, since they are called only from cpu_probe|release_store.
> 
> This patch fixes errors on PowerVM systems that have cpu(s) added/removed
> using dlpar operations; without this patch, the
> /sys/devices/system/cpu/cpuN/online nodes do not correctly show the
> online state of added/removed cpus.

Verified the patch to be working as expected when I online and offline
CPUs of a PowerKVM guest using QEMU (plus my RFC hotplug patchset for
QEMU)

Regards,
Bharata.


  reply	other threads:[~2014-11-02  4:59 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-27  2:59 [PATCH V2] Driver cpu: update online when cpu_up/down besides sysfs Neil Zhang
2014-10-27 21:38 ` Rafael J. Wysocki
2014-10-28  0:46   ` Dan Streetman
2014-10-29 21:46     ` Rafael J. Wysocki
2014-10-29 21:52       ` Dan Streetman
2014-10-30  2:03         ` Neil Zhang
2014-10-31 19:41         ` [PATCH] powerpc: use device_online/offline() instead of cpu_up/down() Dan Streetman
2014-10-31 19:41           ` Dan Streetman
2014-11-02  4:58           ` Bharata B Rao [this message]
2014-11-02  4:58             ` Bharata B Rao
2014-11-03 15:45           ` Nathan Fontenot
2014-10-30  2:00       ` [PATCH V2] Driver cpu: update online when cpu_up/down besides sysfs Neil Zhang

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