linux-kernel - Re: [PATCH] cpufreq: conservative: Take limits changes into account properly

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Message-ID: <20181016095225.snxu3dafz4x3w7ch@vireshk-i7>
Date:   Tue, 16 Oct 2018 15:22:25 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:     Linux PM <linux-pm@...r.kernel.org>,
        Waldemar Rymarkiewicz <waldemar.rymarkiewicz@...il.com>,
        Waldemar Rymarkiewicz <waldemarx.rymarkiewicz@...el.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        t.bartholomae@...el.com
Subject: Re: [PATCH] cpufreq: conservative: Take limits changes into account
 properly

On 15-10-18, 23:21, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> If the policy limits change between invocations of cs_dbs_update(),
> the requested frequency value stored in dbs_info may not be updated
> and the function may use a stale value of it next time.  Moreover, if
> idle periods are takem into account by cs_dbs_update(), the requested
> frequency value stored in dbs_info may be below the min policy limit,
> which is incorrect.
> 
> To fix these problems, always update the requested frequency value
> in dbs_info along with the local copy of it when the previous
> requested frequency is beyond the policy limits and avoid decreasing
> the requested frequency below the min policy limit when taking
> idle periods into account.
> 
> Reported-by: Waldemar Rymarkiewicz <waldemarx.rymarkiewicz@...el.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
>  drivers/cpufreq/cpufreq_conservative.c |    6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

-- 
viresh