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From: Arnd Bergmann <arnd@arndb.de>
To: kbuild test robot <lkp@intel.com>
Cc: "Nicolas Pitre" <nicolas.pitre@linaro.org>,
	kbuild-all@01.org, "Alexey Brodkin" <Alexey.Brodkin@synopsys.com>,
	"Måns Rullgård" <mans@mansr.com>,
	rmk+kernel@arm.linux.org.uk, linux-arch@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/5] do_div(): generic optimization for constant divisor on 32-bit machines
Date: Tue, 03 Nov 2015 10:15:13 +0100	[thread overview]
Message-ID: <21544300.LSjO3j3Xy7@wuerfel> (raw)
In-Reply-To: <201511031333.Yk9ngQZJ%fengguang.wu@intel.com>

On Tuesday 03 November 2015 13:32:17 kbuild test robot wrote:
> 
>    net/can/bcm.c: In function 'bcm_proc_show':
> >> net/can/bcm.c:223:1: warning: the frame size of 1156 bytes is larger than 1024 bytes [-Wframe-larger-than=]
>     }

Interesting, that is a lot of stack for a function that only has a couple
of local variables:

#define IFNAMSIZ        16
        char ifname[IFNAMSIZ];
        struct sock *sk = (struct sock *)m->private;
        struct bcm_sock *bo = bcm_sk(sk);
        struct bcm_op *op;


This is a parisc-allyesconfig kernel, so I assume that CONFIG_PROFILE_ALL_BRANCHES
is on, which instruments every 'if' in the kernel. If that causes problems,
we could decide to disable the do_div optimization whenever CONFIG_PROFILE_ALL_BRANCHES
is enabled.

	Arnd

  reply	other threads:[~2015-11-03  9:16 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-02 22:33 [PATCH 0/5] 64-by-32 ddivision optimization for constant divisors on 32-bit machines Nicolas Pitre
2015-11-02 22:33 ` Nicolas Pitre
2015-11-02 22:33 ` [PATCH 1/5] div64.h: optimize do_div() for power-of-two constant divisors Nicolas Pitre
2015-11-02 22:33   ` Nicolas Pitre
2015-11-02 22:33 ` [PATCH 2/5] do_div(): generic optimization for constant divisor on 32-bit machines Nicolas Pitre
2015-11-03  5:32   ` kbuild test robot
2015-11-03  9:15     ` Arnd Bergmann [this message]
2015-11-04 21:04       ` Nicolas Pitre
2015-11-04 21:42         ` Måns Rullgård
2015-11-04 21:42           ` Måns Rullgård
2015-11-02 22:33 ` [PATCH 3/5] __div64_const32(): abstract out the actual 128-bit cross product code Nicolas Pitre
2015-11-02 22:33   ` Nicolas Pitre
2015-11-02 22:33 ` [PATCH 4/5] __div64_32(): make it overridable at compile time Nicolas Pitre
2015-11-02 22:33   ` Nicolas Pitre
2015-11-02 22:33 ` [PATCH 5/5] ARM: asm/div64.h: adjust to generic codde Nicolas Pitre
2015-11-02 22:33   ` Nicolas Pitre
2015-11-03  1:25   ` kbuild test robot
2015-11-03  4:03     ` Nicolas Pitre
2015-11-03 21:39   ` kbuild test robot
2015-11-19 16:36   ` Måns Rullgård
2015-11-19 16:42     ` Nicolas Pitre
2015-11-19 16:44       ` Måns Rullgård

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