From: Michal Hocko <mhocko@kernel.org>
To: Shuah Khan <shuah@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>,
catalin.marinas@arm.com, sudeep.holla@arm.com,
ganapatrao.kulkarni@cavium.com,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64: add NUMA emulation support
Date: Wed, 5 Sep 2018 08:42:52 +0200 [thread overview]
Message-ID: <20180905064252.GW14951@dhcp22.suse.cz> (raw)
In-Reply-To: <f041ba95-03e6-4a7d-c324-870b45a2f648@kernel.org>
On Tue 04-09-18 15:59:34, Shuah Khan wrote:
[...]
> This will support the following workload requirements:
>
> - reserving one or more NUMA memory nodes for class of critical tasks that require
> guaranteed memory availability.
> - isolate memory blocks with a guaranteed exclusive access.
How do you enforce kernel doesn't allocate from those reserved nodes?
They will be in a fallback zonelists so once the memory gets used on all
other ones then the kernel happily spills over to your reserved node.
> NUMA emulation to split the flat machine into "x" number of nodes, combined with
> cpuset cgroup with the following example configuration will make it possible to
> support the above workloads on non-NUMA platforms.
>
> numa=fake=4
>
> cpuset.mems=2
> cpuset.cpus=2
> cpuset.mem_exclusive=1 (enabling exclusive use of the memory nodes by a CPU set)
> cpuset.mem_hardwall=1 (separate the memory nodes that are allocated to different cgroups)
This will only enforce userspace to follow and I strongly suspect that
tasks in the root cgroup will be allowed to allocate as well.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-09-05 6:42 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-24 23:05 [PATCH] arm64: add NUMA emulation support Shuah Khan (Samsung OSG)
2018-08-28 17:40 ` Will Deacon
2018-08-28 18:09 ` Shuah Khan
2018-08-29 11:08 ` Michal Hocko
2018-09-04 21:59 ` Shuah Khan
2018-09-05 6:42 ` Michal Hocko [this message]
2018-09-06 21:53 ` Shuah Khan
2018-09-07 8:34 ` Michal Hocko
2018-09-07 22:30 ` Shuah Khan
2018-09-10 13:48 ` Michal Hocko
2018-09-11 2:02 ` Shuah Khan
2018-09-11 9:11 ` Michal Hocko
2018-09-11 15:27 ` Shuah Khan
2018-09-11 16:50 ` Will Deacon
2018-09-11 19:53 ` Shuah Khan
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