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From: Punit Agrawal <punit.agrawal@arm.com>
Subject: Re: [PATCH 1/2] arm64: avoid alloc memory on offline node
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Date: Tue, 19 Jun 2018 16:35:40 +0100
In-Reply-To: <20180619151425.GH13685@dhcp22.suse.cz> (Michal Hocko's message
	of "Tue, 19 Jun 2018 17:14:25 +0200")
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To: Michal Hocko <mhocko@kernel.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>, Xie XiuQi <xiexiuqi@huawei.com>, Hanjun Guo <guohanjun@huawei.com>, Bjorn Helgaas <helgaas@kernel.org>, tnowicki@caviumnetworks.com, linux-pci@vger.kernel.org, Catalin Marinas <catalin.marinas@arm.com>, "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>, Will Deacon <will.deacon@arm.com>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>, linux-mm@kvack.org, wanghuiqiang@huawei.com, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Bjorn Helgaas <bhelgaas@google.com>, Andrew Morton <akpm@linux-foundation.org>, zhongjiang <zhongjiang@huawei.com>, linux-arm <linux-arm-kernel@lists.infradead.org>

Michal Hocko <mhocko@kernel.org> writes:

> On Tue 19-06-18 15:54:26, Punit Agrawal wrote:
> [...]
>> In terms of $SUBJECT, I wonder if it's worth taking the original patch
>> as a temporary fix (it'll also be easier to backport) while we work on
>> fixing these other issues and enabling memoryless nodes.
>
> Well, x86 already does that but copying this antipatern is not really
> nice. So it is good as a quick fix but it would be definitely much
> better to have a robust fix. Who knows how many other places might hit
> this. You certainly do not want to add a hack like this all over...

Completely agree! I was only suggesting it as a temporary measure,
especially as it looked like a proper fix might be invasive.

Another fix might be to change the node specific allocation to node
agnostic allocations. It isn't clear why the allocation is being
requested from a specific node. I think Lorenzo suggested this in one of
the threads.

I've started putting together a set fixing the issues identified in this
thread. It should give a better idea on the best course of action.