From: Viresh Kumar <viresh.kumar@linaro.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Linux PM list <linux-pm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Juri Lelli <juri.lelli@arm.com>,
Steve Muckle <steve.muckle@linaro.org>,
Saravana Kannan <skannan@codeaurora.org>
Subject: Re: [PATCH v2 9/10] cpufreq: governor: Rearrange governor data structures
Date: Sun, 7 Feb 2016 14:59:11 +0530 [thread overview]
Message-ID: <20160207092911.GA19059@vireshk> (raw)
In-Reply-To: <2480267.pVUasc5mK9@vostro.rjw.lan>
On 05-02-16, 23:47, Rafael J. Wysocki wrote:
> On Friday, February 05, 2016 02:43:57 PM Viresh Kumar wrote:
> > Value of policy_dbs->policy was used to verify the state machine of
> > the governor and so was updated only in start/stop.
> >
> > You have moved it to INIT first (which shouldn't have been part of
> > this patch at the least),
>
> Why?
Because it doesn't match $SUBJECT at all..
> > and then there is no reasoning given on why
> > that isn't required as part of the state machine now, which I believe
> > is still required the way it was.
>
> No, it isn't required. The whole "state machine" isn't required IMO.
The state machine wasn't required if the core wasn't buggy. Its buggy because we
drop policy->rwsem during set-policy, before calling EXIT. And other
__cpufreq_governor() calls can shoot up at that point of time.
We have seen lots of crashes earlier and so the state machine was introduced to
get them fixed.
It might not be required (after making sure things are working fine now), after
applying my patch series of 7 patches. As that fixes the lock-drop issue ..
> The only user of this is the cpufreq core, so why does the code here have to
> double check what the core is doing?
Because, core doesn't guarantee the order today.
--
viresh
next prev parent reply other threads:[~2016-02-07 9:29 UTC|newest]
Thread overview: 85+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-03 23:12 [PATCH 0/11] cpufreq: governor: ondemand/conservative data structures rework Rafael J. Wysocki
2016-02-03 23:14 ` [PATCH 1/11] cpufreq: Clean up default and fallback governor setup Rafael J. Wysocki
2016-02-04 0:55 ` Saravana Kannan
2016-02-04 5:03 ` Viresh Kumar
2016-02-03 23:16 ` [PATCH 2/11] cpufreq: governor: Use common mutex for dbs_data protection Rafael J. Wysocki
2016-02-04 0:59 ` Saravana Kannan
2016-02-04 5:09 ` Viresh Kumar
2016-02-04 16:46 ` Rafael J. Wysocki
2016-02-05 2:59 ` Viresh Kumar
2016-02-05 3:06 ` Rafael J. Wysocki
2016-02-05 3:15 ` Rafael J. Wysocki
2016-02-05 3:17 ` Rafael J. Wysocki
2016-02-05 3:24 ` Viresh Kumar
2016-02-05 3:33 ` Rafael J. Wysocki
2016-02-05 3:22 ` Viresh Kumar
2016-02-03 23:22 ` [PATCH 3/11] cpufreq: governor: Use common global_dbs_data pointer Rafael J. Wysocki
2016-02-04 1:11 ` Saravana Kannan
2016-02-04 1:25 ` Rafael J. Wysocki
2016-02-04 1:40 ` Saravana Kannan
2016-02-04 5:38 ` Viresh Kumar
2016-02-04 1:47 ` Saravana Kannan
2016-02-04 5:36 ` Viresh Kumar
[not found] ` <CAHZ_5WxJSDtFyFdCc-D2=HSaPON=3rzUxpxPYsCyZvrV1Nv3qw@mail.gmail.com>
2016-02-04 8:25 ` Viresh Kumar
2016-02-04 11:31 ` Gautham R Shenoy
2016-02-04 11:35 ` Viresh Kumar
2016-02-04 16:52 ` Rafael J. Wysocki
2016-02-05 3:02 ` Viresh Kumar
2016-02-05 3:10 ` Rafael J. Wysocki
2016-02-03 23:29 ` [PATCH 4/11] cpufreq: governor: Avoid passing dbs_data pointers around unnecessarily Rafael J. Wysocki
2016-02-04 1:37 ` Saravana Kannan
2016-02-03 23:31 ` [PATCH 5/11] cpufreq: governor: Put governor structure into common_dbs_data Rafael J. Wysocki
2016-02-04 1:57 ` Saravana Kannan
2016-02-03 23:32 ` [PATCH 6/11] cpufreq: governor: Rename some data types and variables Rafael J. Wysocki
2016-02-03 23:33 ` [PATCH 7/11] cpufreq: governor: Rework cpufreq_governor_dbs() Rafael J. Wysocki
2016-02-04 2:03 ` Saravana Kannan
2016-02-03 23:35 ` [PATCH 8/11] cpufreq: governor: Drop the gov pointer from struct dbs_data Rafael J. Wysocki
2016-02-03 23:35 ` [PATCH 9/11] cpufreq: governor: Rename cpu_common_dbs_info to policy_dbs_info Rafael J. Wysocki
2016-02-03 23:37 ` [PATCH 10/11] cpufreq: governor: Rearrange governor data structures Rafael J. Wysocki
2016-02-03 23:38 ` [PATCH 11/11] cpufreq: governor: Drop cpu argument from dbs_check_cpu() Rafael J. Wysocki
2016-02-04 5:40 ` [PATCH 0/11] cpufreq: governor: ondemand/conservative data structures rework Viresh Kumar
2016-02-04 17:22 ` Rafael J. Wysocki
2016-02-05 2:07 ` [PATCH v2 0/10] " Rafael J. Wysocki
2016-02-05 2:11 ` [PATCH v2 1/10] cpufreq: Clean up default and fallback governor setup Rafael J. Wysocki
2016-02-10 5:15 ` Gautham R Shenoy
2016-02-10 5:48 ` Gautham R Shenoy
2016-02-05 2:14 ` [PATCH v2 2/10] cpufreq: governor: Use common mutex for dbs_data protection Rafael J. Wysocki
2016-02-05 6:53 ` Viresh Kumar
2016-02-05 22:59 ` Rafael J. Wysocki
2016-02-07 9:31 ` Viresh Kumar
2016-02-07 14:33 ` Rafael J. Wysocki
2016-02-05 2:15 ` [PATCH v2 3/10] cpufreq: governor: Avoid passing dbs_data pointers around unnecessarily Rafael J. Wysocki
2016-02-05 7:09 ` Viresh Kumar
2016-02-05 2:16 ` [PATCH v2 4/10] cpufreq: governor: Put governor structure into common_dbs_data Rafael J. Wysocki
2016-02-05 7:13 ` Viresh Kumar
2016-02-05 2:17 ` [PATCH v2 5/10] cpufreq: governor: Rename some data types and variables Rafael J. Wysocki
2016-02-05 7:17 ` Viresh Kumar
2016-02-05 2:18 ` [PATCH v2 6/10] cpufreq: governor: Rework cpufreq_governor_dbs() Rafael J. Wysocki
2016-02-05 8:14 ` Viresh Kumar
2016-02-05 2:19 ` [PATCH v2 7/10] cpufreq: governor: Drop the gov pointer from struct dbs_data Rafael J. Wysocki
2016-02-05 8:28 ` Viresh Kumar
2016-02-05 2:20 ` [PATCH v2 8/10] cpufreq: governor: Rename cpu_common_dbs_info to policy_dbs_info Rafael J. Wysocki
2016-02-05 8:34 ` Viresh Kumar
2016-02-05 22:50 ` Rafael J. Wysocki
2016-02-06 12:48 ` [PATCH v3 " Rafael J. Wysocki
2016-02-07 9:31 ` Viresh Kumar
2016-02-05 2:21 ` [PATCH v2 9/10] cpufreq: governor: Rearrange governor data structures Rafael J. Wysocki
2016-02-05 9:13 ` Viresh Kumar
2016-02-05 22:47 ` Rafael J. Wysocki
2016-02-07 9:29 ` Viresh Kumar [this message]
2016-02-07 14:34 ` Rafael J. Wysocki
2016-02-05 2:21 ` [PATCH v2 10/10] cpufreq: governor: Drop cpu argument from dbs_check_cpu() Rafael J. Wysocki
2016-02-05 9:15 ` Viresh Kumar
2016-02-06 12:50 ` [PATCH v3 " Rafael J. Wysocki
2016-02-07 9:32 ` Viresh Kumar
2016-02-06 12:44 ` [PATCH v2 0/10] cpufreq: governor: ondemand/conservative data structures rework Rafael J. Wysocki
2016-02-07 15:22 ` [PATCH 0/3] cpufreq: governor: Data structure rearrangement Rafael J. Wysocki
2016-02-07 15:23 ` [PATCH 1/3] cpufreq: governor: Simplify cpufreq_governor_limits() Rafael J. Wysocki
2016-02-07 15:40 ` Viresh Kumar
2016-02-08 0:59 ` Rafael J. Wysocki
2016-02-07 15:24 ` [PATCH 2/3] cpufreq: governor: Rearrange governor data structures Rafael J. Wysocki
2016-02-07 15:45 ` Viresh Kumar
2016-02-07 15:54 ` Viresh Kumar
2016-02-07 15:55 ` Viresh Kumar
2016-02-07 15:25 ` [PATCH 3/3] cpufreq: governor: Symmetrize cpu_dbs_info initialization and cleanup Rafael J. Wysocki
2016-02-07 15:52 ` Viresh Kumar
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