linux-kernel - Re: [PATCH 3/3] ARM 4Kstacks: Decrease poll and select stack usage, when using 4K stacks

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Date:	Thu, 20 Oct 2011 14:21:43 +0200
From:	Arnd Bergmann <arnd@...db.de>
To:	Tim Bird <tim.bird@...sony.com>
Cc:	Russell King <rmk@....linux.org.uk>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Andi Kleen <andi@...stfloor.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] ARM 4Kstacks: Decrease poll and select stack usage, when using 4K stacks

On Wednesday 19 October 2011, Tim Bird wrote:
> Reduce the max allowed size for struct poll_wqueue to avoid
> using too much stack space in do_select() and do_sys_poll(),
> when the kernel is using 4K stacks.
> 
> Signed-off-by: Tim Bird <tim.bird@...sony.com>

Can you explain why this is necessary with 4K stacks? I would
expect the poll() function never to be deeply nested, so 1K
used in there doesn't sound too problematic.

	Arnd
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