Message-ID: <4FCB4F00.8080202@linux.vnet.ibm.com>
Date: Sun, 03 Jun 2012 17:18:16 +0530
From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
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To: Yong Zhang <yong.zhang0@gmail.com>
CC: tglx@linutronix.de, peterz@infradead.org, paulmck@linux.vnet.ibm.com,
        rusty@rustcorp.com.au, mingo@kernel.org, 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,
        Ralf Baechle <ralf@linux-mips.org>,
        Eric Dumazet <eric.dumazet@gmail.com>,
        Mike Frysinger <vapier@gentoo.org>,
        David Howells <dhowells@redhat.com>, Arun Sharma <asharma@fb.com>,
        linux-mips@linux-mips.org
Subject: Re: [PATCH 10/27] mips, smpboot: Use generic SMP booting infrastructure
References: <20120601090952.31979.24799.stgit@srivatsabhat.in.ibm.com> <20120601091226.31979.62223.stgit@srivatsabhat.in.ibm.com> <20120603082507.GA16829@zhy>
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On 06/03/2012 01:55 PM, Yong Zhang wrote:

> On Fri, Jun 01, 2012 at 02:42:32PM +0530, Srivatsa S. Bhat wrote:
>> Convert mips to use the generic framework to boot secondary CPUs.
>>
>> Notes:
>> 1. The boot processor was setting the secondary cpu in cpu_online_mask!
>> Instead, leave it up to the secondary cpu (... and it will be done by the
>> generic code now).
>>
>> 2. Make the boot cpu wait for the secondary cpu to be set in cpu_online_mask
>> before returning.
> 
> We don't need to wait for both cpu_callin_map (The code above yours)
> any more.


Yes, I noticed that while writing the patch. But then, I thought of cleaning
up the hundreds of callin/callout/commenced maps in various architectures and
bringing them out into core code in a later series, and clean this up at that time..
I didn't want to do too many invasive changes all at one-shot.

But I guess for this particular case of mips, I can get rid of the wait for
cpu_callin_map in this patchset itself. I'll update this patch with that change.

Thanks!

> 
>>
>> 3. Don't enable interrupts in cmp_smp_finish() and vsmp_smp_finish().
>> Do it much later, in generic code.
> 
> Hmmm... the bad thing is that some board enable irq more early than
> ->smp_finish(), I have sent patches for that (by moving irq enable
> to smp_finish() and delaying smp_finish()).
> Please check patch#0001~patch#0004 in
> http://marc.info/?l=linux-mips&m=133758022710973&w=2
> 
>>
>> 4. In synchronise_count_slave(), use local_save_flags() instead of
>> local_irq_save() because irqs are still disabled.
> 
> We can just remove local_irq_save()/local_irq_restore() like:
> http://marc.info/?l=linux-mips&m=133758046211043&w=2
> 


So what is the status of those patches? Has anyone picked them up?

I could rebase this patch on top of yours, or better yet, if your
patches haven't been picked up yet, I could include them in this
patchset itself to avoid too many dependencies on external patches.

What do you say?

Regards,
Srivatsa S. Bhat

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