From mboxrd@z Thu Jan  1 00:00:00 1970
From: catalin.marinas@arm.com (Catalin Marinas)
Date: Fri, 4 Dec 2015 13:57:52 +0000
Subject: [PATCH v8 0/4] arm64: Add support for IRQ stack
In-Reply-To: <1449226948-14251-1-git-send-email-james.morse@arm.com>
References: <1449226948-14251-1-git-send-email-james.morse@arm.com>
Message-ID: <20151204135752.GK10123@e104818-lin.cambridge.arm.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Fri, Dec 04, 2015 at 11:02:24AM +0000, James Morse wrote:
> Patch 4 is new, following Catalin's comments, but I don't think it is
> necessary unless we also decrease the stack size,

That's the whole aim of this patchset, to try to to get back to 8KB
stacks.

> which I don't think we should do immediatly - it would be good to
> collect some max_stack_size values for various workloads first.

We could make it configurable though, maybe defaulting to 16KB for a
while.

IIRC, the stack overflows we had in the past were triggered when running
specweb but I don't remember whether it was hard or soft IRQs that
caused the issues (could have been both). We could run some tests again
and see how close we get to the 8KB limit.

BTW, what's the disadvantage of always switching to the IRQ stack in
do_softirq?

-- 
Catalin