From: "Michal Nazarewicz" <mina86@mina86.com>
To: linux-kernel@vger.kernel.org, "Gilad Ben-Yossef" <gilad@benyossef.com>
Cc: "David Airlie" <airlied@linux.ie>,
dri-devel@lists.freedesktop.org,
"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
"Paul Mackerras" <paulus@samba.org>,
"Grant Likely" <grant.likely@secretlab.ca>,
"Rob Herring" <rob.herring@calxeda.com>,
linuxppc-dev@lists.ozlabs.org,
devicetree-discuss@lists.ozlabs.org,
"Richard Henderson" <rth@twiddle.net>,
"Ivan Kokshaysky" <ink@jurassic.park.msu.ru>,
"Matt Turner" <mattst88@gmail.com>,
linux-alpha@vger.kernel.org,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, "Tony Luck" <tony.luck@intel.com>,
"Fenghua Yu" <fenghua.yu@intel.com>,
linux-ia64@vger.kernel.org, "Will Deacon" <will.deacon@arm.com>,
"Peter Zijlstra" <a.p.zijlstra@chello.nl>,
"Arnaldo Carvalho de Melo" <acme@ghostprotocols.net>,
"Russell King" <linux@arm.linux.org.uk>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH 0/9] Remove useless on_each_cpu return value
Date: Tue, 03 Jan 2012 15:25:49 +0100 [thread overview]
Message-ID: <op.v7iidbwz3l0zgt@mpn-glaptop> (raw)
In-Reply-To: <1325600353-10895-1-git-send-email-gilad@benyossef.com>
On Tue, 03 Jan 2012 15:19:04 +0100, Gilad Ben-Yossef <gilad@benyossef.com> wrote:
> on_each_cpu() returns as its own return value the return value of
> smp_call_function(). smp_call_function() in turn returns a hard
> coded value of zero.
>
> Some callers to on_each_cpu() waste cycles and bloat code space
> by checking the return value to on_each_cpu(), probably for
> historical reasons.
>
> This patch set refactors callers to not test on_each_cpu()
> (fixed) return value and then refactors on_each_cpu to
> return void to avoid confusing future users.
>
> In other words, this patch aims to delete 18 source code lines
> while not changing any functionality :-)
>
> I tested as best as I could the x86 changes and compiled some
> of the others, but I don't have access to all the needed hardware
> for testing. Reviewers and testers welcome!
Other then the lack of Signed-off-by in the patches, looks good to me,
even though personally I'd choose a bottom-up approach, ie. make
smp_call_function() return void and from that conclude that
on_each_cpu() can return void. With those patches, we have a situation,
where smp_call_function() has a return value which is then lost for no
immediately apparent reason lost in on_each_cpu().
--
Best regards, _ _
.o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michał “mina86” Nazarewicz (o o)
ooo +----<email/xmpp: mpn@google.com>--------------ooO--(_)--Ooo--
next prev parent reply other threads:[~2012-01-03 14:26 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-03 14:19 Gilad Ben-Yossef
2012-01-03 14:19 ` [RFC PATCH 1/9] arm: avoid using on_each_cpu hard coded ret value Gilad Ben-Yossef
2012-01-09 8:28 ` Uwe Kleine-König
2012-01-03 14:19 ` [RFC PATCH 2/9] ia64: " Gilad Ben-Yossef
2012-01-03 14:19 ` [RFC PATCH 3/9] x86: " Gilad Ben-Yossef
2012-01-03 14:19 ` [RFC PATCH 4/9] alpha: " Gilad Ben-Yossef
2012-01-03 14:19 ` [RFC PATCH 5/9] ppc: " Gilad Ben-Yossef
2012-01-03 14:19 ` [RFC PATCH 6/9] agp: " Gilad Ben-Yossef
2012-01-03 14:19 ` [RFC PATCH 7/9] drm: " Gilad Ben-Yossef
2012-01-03 14:19 ` [RFC PATCH 8/9] smp: refactor on_each_cpu to void returning func Gilad Ben-Yossef
2012-01-03 14:19 ` [RFC PATCH 9/9] x86: refactor wbinvd_on_all_cpus to void function Gilad Ben-Yossef
2012-01-03 14:25 ` Michal Nazarewicz [this message]
2012-01-03 16:08 ` [RFC PATCH 0/9] Remove useless on_each_cpu return value Gilad Ben-Yossef
2012-01-06 13:03 ` Peter Zijlstra
2012-01-08 16:10 ` Gilad Ben-Yossef
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