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From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Sam Ravnborg <sam@ravnborg.org>,
	peterz@infradead.org, paulmck@linux.vnet.ibm.com,
	rusty@rustcorp.com.au, mingo@kernel.org, yong.zhang0@gmail.com,
	akpm@linux-foundation.org, vatsa@linux.vnet.ibm.com, rjw@sisk.pl,
	linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	nikunj@linux.vnet.ibm.com,
	Suresh Siddha <suresh.b.siddha@intel.com>,
	Venkatesh Pallipadi <venki@google.com>
Subject: Re: [PATCH 01/27] smpboot: Provide a generic method to boot secondary processors
Date: Mon, 04 Jun 2012 22:23:15 +0530	[thread overview]
Message-ID: <4FCCE7FB.3000301@linux.vnet.ibm.com> (raw)
In-Reply-To: <alpine.LFD.2.02.1206041513000.3086@ionos>

On 06/04/2012 06:48 PM, Thomas Gleixner wrote:

> On Mon, 4 Jun 2012, Srivatsa S. Bhat wrote:
>> On 06/04/2012 04:02 PM, Thomas Gleixner wrote:
>> I can add the prototype w/o the __weak prefix and the #ifndef magic in
>> include/linux/smpboot.h (which I will, and include it in v2).
>>
>> However, I can't get rid of the #ifndef magic in kernel/smpboot.c because
>> it will cause build failures on x86.
>>
>> I addressed this same issue in another email:
>> https://lkml.org/lkml/2012/6/3/33
> 
>> In short, to avoid breaking build on x86.
>> We wanted to follow the x86 convention of having static inline functions in
>> arch/x86/include/asm/smp.h and use the smp_ops structure to route the calls
>> to x86 or xen as appropriate (see patch 4 in this series).
> 
> Oh no. That's not really a good argument.
> 
> There is no reason why this _must_ be an inline function on x86. It
> can be a proper function in arch/x86/kernel/smpboot.c as well.
> 


Ok, I'll adopt this approach.

> The alternative solution is to generalize the smp_ops approach and get
> rid of the weak implementations completely.
> 


Ok, but this would mean changes to all architectures, which could be avoided.

One reason why x86 uses that smp_ops structure is because it decides the
implementation routines between x86 and xen at run-time. Such requirements don't
exist on other architectures, from what I saw (except sparc32).

So I'll stick with the former approach of adding a proper function for x86, and
retaining the default weak implementations in kernel/smpboot.c.
 
Regards,
Srivatsa S. Bhat


  reply	other threads:[~2012-06-04 16:55 UTC|newest]

Thread overview: 91+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-01  9:10 [PATCH 00/27] Generic framework for SMP booting/CPU hotplug related code Srivatsa S. Bhat
2012-06-01  9:10 ` [PATCH 01/27] smpboot: Provide a generic method to boot secondary processors Srivatsa S. Bhat
2012-06-01 12:09   ` Srivatsa S. Bhat
2012-06-03  8:51     ` Yong Zhang
2012-06-03 11:22       ` Srivatsa S. Bhat
2012-06-04  2:18         ` Yong Zhang
2012-06-03  8:53     ` Yong Zhang
2012-06-03 11:33       ` Srivatsa S. Bhat
2012-06-03 11:39         ` Russell King - ARM Linux
2012-06-03 12:05           ` Srivatsa S. Bhat
2012-06-01 16:51   ` Sam Ravnborg
2012-06-01 22:29     ` Srivatsa S. Bhat
2012-06-04 10:32       ` Thomas Gleixner
2012-06-04 13:07         ` Srivatsa S. Bhat
2012-06-04 13:18           ` Thomas Gleixner
2012-06-04 16:53             ` Srivatsa S. Bhat [this message]
2012-06-05  5:11           ` Yong Zhang
2012-06-05  6:07             ` Srivatsa S. Bhat
2012-06-01 16:53   ` Sam Ravnborg
2012-06-01 22:41     ` Srivatsa S. Bhat
2012-06-02 15:16       ` Sam Ravnborg
2012-06-02 15:34         ` Srivatsa S. Bhat
2012-06-01  9:10 ` [PATCH 02/27] smpboot: Add provisions for arch-specific locking around cpu_online_mask Srivatsa S. Bhat
2012-06-01 12:12   ` Srivatsa S. Bhat
2012-06-01  9:11 ` [PATCH 04/27] smpboot, x86, xen: Determine smp booting implementations at run-time Srivatsa S. Bhat
2012-06-01  9:11 ` [PATCH 05/27] xen, cpu hotplug: Don't call cpu_bringup() in xen_play_dead() Srivatsa S. Bhat
2012-06-01 12:59   ` [Xen-devel] " Jan Beulich
2012-06-01 15:13     ` Srivatsa S. Bhat
2012-06-01 15:36       ` Jan Beulich
2012-06-02 18:06         ` Srivatsa S. Bhat
2012-06-05 16:49           ` Konrad Rzeszutek Wilk
2012-06-05 17:36             ` Srivatsa S. Bhat
2012-06-05 17:40           ` Thomas Gleixner
2012-06-05 17:48             ` Srivatsa S. Bhat
2012-06-01  9:11 ` [PATCH 06/27] xen, smpboot: Use generic SMP booting infrastructure Srivatsa S. Bhat
2012-06-01  9:11 ` [PATCH 07/27] x86, " Srivatsa S. Bhat
2012-06-04 14:29   ` Thomas Gleixner
2012-06-04 17:00     ` Srivatsa S. Bhat
2012-06-01  9:12 ` [PATCH 08/27] m32r: Fix horrible logic in smp_prepare_cpus() Srivatsa S. Bhat
2012-06-01  9:12 ` [PATCH 09/27] m32r, smpboot: Use generic SMP booting infrastructure Srivatsa S. Bhat
2012-06-01  9:12 ` [PATCH 10/27] mips, " Srivatsa S. Bhat
2012-06-03  8:25   ` Yong Zhang
2012-06-03 11:48     ` Srivatsa S. Bhat
2012-06-04  2:17       ` Yong Zhang
2012-06-01  9:12 ` [PATCH 11/27] sh, " Srivatsa S. Bhat
2012-06-01  9:12 ` [PATCH 12/27] tile, " Srivatsa S. Bhat
2012-06-01 18:07   ` Chris Metcalf
2012-06-01  9:13 ` [PATCH 13/27] hexagon, " Srivatsa S. Bhat
2012-06-01  9:13 ` [PATCH 14/27] ia64: Move holding of vector_lock to __setup_vector_irq() Srivatsa S. Bhat
2012-06-01  9:13 ` [PATCH 15/27] ia64, smpboot: Use generic SMP booting infrastructure Srivatsa S. Bhat
2012-06-01  9:13 ` [PATCH 16/27] mn10300: Fix horrible logic in smp_prepare_cpus() Srivatsa S. Bhat
2012-06-01  9:14 ` [PATCH 17/27] mn10300, smpboot: Use generic SMP booting infrastructure Srivatsa S. Bhat
2012-06-03  8:33   ` Yong Zhang
2012-06-03 11:50     ` Srivatsa S. Bhat
2012-06-01  9:14 ` [PATCH 18/27] powerpc, " Srivatsa S. Bhat
2012-06-02  6:14   ` Paul Mackerras
2012-06-01  9:14 ` [PATCH 19/27] blackfin, " Srivatsa S. Bhat
2012-06-01  9:14 ` [PATCH 20/27] sparc64, " Srivatsa S. Bhat
2012-06-01 17:55   ` David Miller
2012-06-01 22:44     ` [UPDATED PATCH " Srivatsa S. Bhat
2012-06-01 22:52       ` David Miller
2012-06-01  9:15 ` [PATCH 21/27] sparc32, " Srivatsa S. Bhat
2012-06-01 17:56   ` David Miller
2012-06-01 18:54     ` Sam Ravnborg
2012-06-01 22:47       ` [UPDATED PATCH " Srivatsa S. Bhat
2012-06-01 22:53         ` David Miller
2012-06-01 23:17           ` Srivatsa S. Bhat
2012-06-02  6:52         ` Sam Ravnborg
2012-06-02  7:44           ` Sam Ravnborg
2012-06-02  8:01             ` Srivatsa S. Bhat
2012-06-02  8:14               ` Srivatsa S. Bhat
2012-06-02 15:13               ` Sam Ravnborg
2012-06-02 15:58                 ` Srivatsa S. Bhat
2012-06-02 16:23                   ` Sam Ravnborg
2012-06-02 16:34                     ` Srivatsa S. Bhat
2012-06-03 21:17                       ` [PATCH] sparc32: refactor smp boot Sam Ravnborg
2012-06-04  1:04                         ` David Miller
2012-06-04  6:48                         ` Srivatsa S. Bhat
2012-06-01  9:15 ` [PATCH 22/27] um, smpboot: Use generic SMP booting infrastructure Srivatsa S. Bhat
2012-06-01  9:15 ` [PATCH 23/27] cris, " Srivatsa S. Bhat
2012-06-03  8:41   ` Yong Zhang
2012-06-03 11:52     ` Srivatsa S. Bhat
2012-06-01  9:15 ` [PATCH 24/27] parisc, " Srivatsa S. Bhat
2012-06-01  9:16 ` [PATCH 25/27] s390, " Srivatsa S. Bhat
2012-06-01 10:45   ` Heiko Carstens
2012-06-01  9:16 ` [PATCH 26/27] arm, " Srivatsa S. Bhat
2012-06-01 11:04   ` Russell King - ARM Linux
2012-06-01  9:16 ` [PATCH 27/27] alpha, " Srivatsa S. Bhat
     [not found] ` <20120601091038.31979.67878.stgit@srivatsabhat.in.ibm.com>
2012-06-01 12:19   ` [PATCH 03/27] smpboot: Define and use cpu_state per-cpu variable in generic code Srivatsa S. Bhat
2012-06-01 12:25     ` Russell King - ARM Linux
2012-06-01 12:55       ` Srivatsa S. Bhat

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