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From: Michael Ellerman <mpe@ellerman.id.au>
To: Christophe Leroy <christophe.leroy@c-s.fr>, linuxppc-dev@ozlabs.org
Subject: Re: [PATCH 1/2] powerpc: Use seq_buf to avoid pr_cont() in __die()
Date: Thu, 10 Jan 2019 21:54:28 +1100	[thread overview]
Message-ID: <87k1jcsryz.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <53b82835-630a-beb9-8a4e-5badc07960c9@c-s.fr>

Christophe Leroy <christophe.leroy@c-s.fr> writes:
> Le 08/01/2019 à 13:04, Michael Ellerman a écrit :
>> Using pr_cont() risks having our output interleaved with other output
>> from other CPUs. Instead use a seq_buf to construct the line and then
>> print it as a whole.
>
> Why not simply doing a single printk() or similar on the same model as 
> X86 for instance ? 
> (https://elixir.bootlin.com/linux/v5.0-rc1/source/arch/x86/kernel/dumpstack.c#L368)

Yeah we could do it that way, though it can become a bit of a mess.

In this case I guess it's not *too* bad:

	printk("%s PAGE_SIZE=%luK%s%s%s%s%s %s\n",
	       IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) ? "LE" : "BE",
	       PAGE_SIZE / 1024,
	       IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "",
	       IS_ENABLED(CONFIG_SMP) ? " SMP" : "",
	       IS_ENABLED(CONFIG_SMP) ? (" NR_CPUS=" __stringify(NR_CPUS)) : "",
	       debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "",
	       IS_ENABLED(CONFIG_NUMA) ? " NUMA" : "",
	       ppc_md.name ? ppc_md.name : "");

And the generated code is obviously a lot smaller.

So yeah I'll go with that. Thanks for the review.

cheers

      reply	other threads:[~2019-01-10 10:56 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-08 12:04 [PATCH 1/2] powerpc: Use seq_buf to avoid pr_cont() in __die() Michael Ellerman
2019-01-08 12:05 ` [PATCH 2/2] powerpc: Show PAGE_SIZE in __die() output Michael Ellerman
2019-01-08 12:21   ` Christophe Leroy
2019-01-09  7:47     ` Christophe Leroy
2019-01-10  1:02       ` Michael Ellerman
2019-01-08 12:18 ` [PATCH 1/2] powerpc: Use seq_buf to avoid pr_cont() in __die() Christophe Leroy
2019-01-10 10:54   ` Michael Ellerman [this message]

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