From: Thomas Gleixner <tglx@linutronix.de>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
Andrea Arcangeli <aarcange@redhat.com>,
Waiman Long <longman@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Jiri Kosina <jikos@kernel.org>
Subject: Re: [PATCH] cpu/hotplug: Create SMT sysfs interface for all arches
Date: Tue, 26 Mar 2019 19:34:57 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.21.1903261934280.1789@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190326180348.fzerpltlf62dnurd@treble>
On Tue, 26 Mar 2019, Josh Poimboeuf wrote:
> On Tue, Mar 26, 2019 at 02:53:04PM +0100, Thomas Gleixner wrote:
> > > Makes sense. I like #3. I can post another version.
> >
> > Yes, please.
>
> Something like so (on top of the original patch)?
>
> diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
> index 4a11cba73085..5eea46fefcb2 100644
> --- a/Documentation/ABI/testing/sysfs-devices-system-cpu
> +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
> @@ -511,11 +511,12 @@ Description: Control Symetric Multi Threading (SMT)
> control: Read/write interface to control SMT. Possible
> values:
>
> - "on" SMT is enabled
> - "off" SMT is disabled
> - "forceoff" SMT is force disabled. Cannot be changed.
> - "notsupported" Runtime SMT toggling is not currently
> - supported for the architecture
> + "on" SMT is enabled
> + "off" SMT is disabled
> + "forceoff" SMT is force disabled. Cannot be changed.
> + "notsupported" SMT is not supported by the CPU
> + "notimplemented" SMT runtime toggling is not
> + implemented for the architecture
>
> If control status is "forceoff" or "notsupported" writes
> are rejected.
> diff --git a/kernel/cpu.c b/kernel/cpu.c
> index 517ab1803a22..05a71ee98440 100644
> --- a/kernel/cpu.c
> +++ b/kernel/cpu.c
> @@ -2145,7 +2145,11 @@ static const char *smt_states[] = {
> static ssize_t
> show_smt_control(struct device *dev, struct device_attribute *attr, char *buf)
> {
> - return snprintf(buf, PAGE_SIZE - 2, "%s\n", smt_states[cpu_smt_control]);
> + const char *state = IS_ENABLED(CONFIG_HOTPLUG_SMT) ?
> + smt_states[cpu_smt_control] :
> + "notimplemented";
> +
> + return snprintf(buf, PAGE_SIZE - 2, "%s\n", state);
> }
Looks good!
Thanks,
tglx
prev parent reply other threads:[~2019-03-26 18:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-01 17:42 [PATCH] cpu/hotplug: Create SMT sysfs interface for all arches Josh Poimboeuf
2019-03-06 15:44 ` Thomas Gleixner
2019-03-24 20:13 ` Thomas Gleixner
2019-03-26 13:32 ` Josh Poimboeuf
2019-03-26 13:53 ` Thomas Gleixner
2019-03-26 18:03 ` Josh Poimboeuf
2019-03-26 18:34 ` Thomas Gleixner [this message]
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