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From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Eduardo Valentin <edubezval@gmail.com>
Cc: Rui Zhang <rui.zhang@intel.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Len Brown <lenb@kernel.org>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	"Lee, Chun-Yi" <jlee@suse.com>,
	Darren Hart <dvhart@infradead.org>, Keerthy <j-keerthy@ti.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux OMAP Mailing List <linux-omap@vger.kernel.org>,
	platform-driver-x86@vger.kernel.org,
	"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>
Subject: Re: [PATCH 1/1] thermal: core: call thermal_zone_device_update() after mode update
Date: Thu, 23 Jun 2016 14:27:12 +0200	[thread overview]
Message-ID: <CAJZ5v0hRosrpW50Jx3p6-yHmNFLEaHpf9htfevtunEa10Jo7Dg@mail.gmail.com> (raw)
In-Reply-To: <1466571990-12346-1-git-send-email-edubezval@gmail.com>

On Wed, Jun 22, 2016 at 7:06 AM, Eduardo Valentin <edubezval@gmail.com> wrote:
> Because several drivers do the following pattern:
> .set_mode()
>    ...
>    local_data->mode = new_mode;
>    thermal_zone_device_update(tz);
>
> makes sense to simply do the thermal_zone_device_update()
> in thermal core, after setting the new mode.
>
> Also, this patch also remove deadlocks on drivers that
> call thermal_zone_device_update() on .set_mode(),
> as .set_mode()  is now called always with tz->lock held.

To me, this part of the patch is way more important than the
optimization mentioned before.

Apparently, the problem is that drivers deadlock, because the
thermal_zone_device_update() invoked from ->set_mode() is called under
tz->lock.

So to address that problem you make the core call
thermal_zone_device_update() after ->set_mode() outside of tz->lock
and the drivers don't have to do it any more.

Is that correct?

Thanks,
Rafael

  reply	other threads:[~2016-06-23 12:27 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-31  6:31 [PATCH 00/15] thermal: sysfs: add locking Eduardo Valentin
2016-05-31  6:31 ` [PATCH 01/15] thermal: sysfs: lock tz in type_show Eduardo Valentin
2016-05-31  6:31 ` [PATCH 02/15] thermal: sysfs: lock tz while on access to mode properties Eduardo Valentin
2016-06-07  9:08   ` Keerthy
2016-06-07  9:22     ` Keerthy
2016-06-22  2:45       ` Zhang Rui
2016-06-22  5:06         ` [PATCH 1/1] thermal: core: call thermal_zone_device_update() after mode update Eduardo Valentin
2016-06-23 12:27           ` Rafael J. Wysocki [this message]
2016-06-23 12:37             ` Keerthy
2016-07-01 20:53             ` Eduardo Valentin
2016-06-22  5:15         ` [PATCHv2 " Eduardo Valentin
2016-06-22  9:33           ` Keerthy
2016-06-22 14:36             ` Eduardo Valentin
2016-06-22 15:05               ` Eduardo Valentin
2016-06-22 14:34         ` [PATCHv3 " Eduardo Valentin
2016-06-22 15:03         ` [PATCHv4 " Eduardo Valentin
2016-06-23  4:38           ` Keerthy
2016-06-23  4:51           ` Darren Hart
2016-06-29  6:23           ` Zhang Rui
2016-07-01 20:57             ` Eduardo Valentin
2016-07-03  9:03           ` Peter Feuerer
2016-07-02  2:49   ` [PATCHv2 1/1] thermal: sysfs: lock tz while on access to mode properties Eduardo Valentin
2016-05-31  6:31 ` [PATCH 03/15] thermal: sysfs: lock tz while on trip_point_type properties Eduardo Valentin
2016-05-31  6:31 ` [PATCH 04/15] thermal: sysfs: lock tz while on trip_point_temp properties Eduardo Valentin
2016-05-31  6:31 ` [PATCH 05/15] thermal: sysfs: lock tz while on trip_point_hyst properties Eduardo Valentin
2016-05-31  6:31 ` [PATCH 06/15] thermal: sysfs: lock tz while on passive properties Eduardo Valentin
2016-05-31  6:31 ` [PATCH 07/15] thermal: sysfs: lock tz while on policy properties Eduardo Valentin
2016-05-31  6:31 ` [PATCH 08/15] thermal: sysfs: improve locking of emul_temp_store() Eduardo Valentin
2016-05-31  6:31 ` [PATCH 09/15] thermal: sysfs: lock tz when access sustainable power properties Eduardo Valentin
2016-05-31  6:31 ` [PATCH 10/15] thermal: sysfs: lock tz when access tzp properties Eduardo Valentin
2016-05-31  6:31 ` [PATCH 11/15] thermal: sysfs: lock cdev while accessing type Eduardo Valentin
2016-05-31  6:31 ` [PATCH 12/15] thermal: sysfs: lock cdev while accessing max_state Eduardo Valentin
2016-05-31  6:31 ` [PATCH 13/15] thermal: sysfs: lock cdev while accessing cur_state Eduardo Valentin
2016-05-31  6:31 ` [PATCH 14/15] thermal: sysfs: serialize access to instances Eduardo Valentin
2016-05-31  6:31 ` [PATCH 15/15] thermal: sysfs: add comments describing locking strategy Eduardo Valentin
2016-06-01  3:56 ` [PATCH 00/15] thermal: sysfs: add locking Keerthy

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