From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: John Hubbard <jhubbard@nvidia.com>
Cc: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>,
LKML <linux-kernel@vger.kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Preeti U Murthy <preeti@linux.vnet.ibm.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
linux-pm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v3] cpufreq: powernv: fix stack bloat and hard limit on num cpus
Date: Mon, 04 Nov 2019 12:06:59 +0100 [thread overview]
Message-ID: <8351130.8dpKiuZLPc@kreacher> (raw)
In-Reply-To: <20191031052159.4125031-1-jhubbard@nvidia.com>
On Thursday, October 31, 2019 6:21:59 AM CET John Hubbard wrote:
> The following build warning occurred on powerpc 64-bit builds:
>
> drivers/cpufreq/powernv-cpufreq.c: In function 'init_chip_info':
> drivers/cpufreq/powernv-cpufreq.c:1070:1: warning: the frame size of
> 1040 bytes is larger than 1024 bytes [-Wframe-larger-than=]
>
> This is with a cross-compiler based on gcc 8.1.0, which I got from:
> https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/8.1.0/
>
> The warning is due to putting 1024 bytes on the stack:
>
> unsigned int chip[256];
>
> ...and it's also undesirable to have a hard limit on the number of
> CPUs here.
>
> Fix both problems by dynamically allocating based on num_possible_cpus,
> as recommended by Michael Ellerman.
>
> Fixes: 053819e0bf840 ("cpufreq: powernv: Handle throttling due to Pmax capping at chip level")
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
> Cc: Viresh Kumar <viresh.kumar@linaro.org>
> Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
> Cc: linux-pm@vger.kernel.org
> Cc: linuxppc-dev@lists.ozlabs.org
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
>
> Changes since v2: applied fixes from Michael Ellerman's review:
>
> * Changed from CONFIG_NR_CPUS to num_possible_cpus()
>
> * Fixed up commit description: added a note about exactly which
> compiler generates the warning. And softened up wording about
> the limitation on number of CPUs.
>
> Changes since v1: includes Viresh's review commit fixes.
Applying as 5.5 material, thanks!
prev parent reply other threads:[~2019-11-04 11:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-31 5:21 [PATCH v3] cpufreq: powernv: fix stack bloat and hard limit on num cpus John Hubbard
2019-10-31 9:22 ` Viresh Kumar
2019-11-04 11:06 ` Rafael J. Wysocki [this message]
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