linux-kernel - Re: [Patch v2] align crash_notes allocation to make it be inside one physical page

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Message-ID: <20150811063333.GB9748@dhcp-17-102.nay.redhat.com>
Date:	Tue, 11 Aug 2015 14:33:33 +0800
From:	Baoquan He <bhe@...hat.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	ebiederm@...ssion.com, vgoyal@...hat.com, dyoung@...hat.com,
	mhuang@...hat.com, lisa.mitchell@...com, tatsu@...jp.nec.com,
	seiji.aguchi.tr@...achi.com, linux-kernel@...r.kernel.org,
	kexec@...ts.infradead.org
Subject: Re: [Patch v2] align crash_notes allocation to make it be inside one
 physical page

Hi Andrew,

On 08/03/15 at 03:04pm, Andrew Morton wrote:
> On Mon,  3 Aug 2015 20:50:43 +0800 Baoquan He <bhe@...hat.com> wrote:
> And I think the WARN_ON can be replaced with a
> BUILD_BUG_ON(sizeof>PAGE_SIZE)?  That would avoid adding runtime
> overhead.

Rethink about this, you are right. Using BUILD_BUG_ON is better.
Anyone who found this compiling break should check if his/her code
changes increase the crash_notes size. If possible that increase need be
avoidable. Otherwise he should report this to upstream why it's
unavoidable to increase crash_notes size, then let's consider the
redesign the crash_notes data structure. 

So I will use BUILD_BUG_ON and repost.

Thanks
Baoquan
> 
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