From: Thiago Jung Bauermann <bauerman@linux•vnet.ibm.com>
To: linuxppc-dev@lists•ozlabs.org
Cc: Michael Ellerman <mpe@ellerman•id.au>,
Sukadev Bhattiprolu <sukadev@linux•vnet.ibm.com>,
Paul Clarke <pc@us•ibm.com>,
linux-kernel@vger•kernel.org
Subject: Re: [PATCH 2/2] powerpc/pseries: Dynamically increase RMA size
Date: Wed, 01 Feb 2017 15:49:23 -0200 [thread overview]
Message-ID: <2499748.LKgOIUjhgo@morokweng> (raw)
In-Reply-To: <87wpdatqrt.fsf@concordia.ellerman.id.au>
Hello,
Am Mittwoch, 1. Februar 2017, 16:37:58 BRST schrieb Michael Ellerman:
> Sukadev Bhattiprolu <sukadev@linux•vnet.ibm.com> writes:
> > Paul Clarke [pc@us•ibm.com] wrote:
> > ---
> >=20
> > From f9e9e8460206bc3fa7eaa741b9a2bde22870b9e0 Mon Sep 17 00:00:00 2001
>=20
> I know it's been a while but I think it would still be good to get this
> in a shape that we can merge it.
Sorry if this has been tried and didn't work or if I'm missing something=20
obvious:
Instead of this method of trying a small RMA size and rebooting to try a=20
bigger size, could the "min RMA percentage of total RAM" field of the=20
ibm_architecture_vec be used?
LoPAPR says that "The Initial size of the RMA is set to the greater of the=
=20
values indicated by bytes 24-27 [min RMA] or 32 [min RMA percentage of tota=
l=20
RAM] of option vector number 2 =E2=80=9COpen Firmware=E2=80=9D or minimum R=
MA size supported=20
by the platform and capped by the maximum memory defined for the partition =
and=20
the maximum size of the RMA supported by the platform. The respective selec=
ted=20
values are reported in the length of the first memory property."
My understanding is that these patches are intended for big guests with man=
y=20
processors, but the RMA size isn't changed to 512MB outright because of=20
worries that it could affect smaller guests. Since guests with many process=
ors=20
tend to have more RAM as well, specifying a min RMA size of 256MB and a min=
=20
RMA percentage of, say, 10% or 20% could make the host automatically alloca=
te=20
an adequate RMA size in the first boot.
=2D-=20
Thiago Jung Bauermann
IBM Linux Technology Center
next prev parent reply other threads:[~2017-02-01 17:49 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-05 6:10 [PATCH 1/2] powerpc/pseries: Use a helper to fixup nr_cores Sukadev Bhattiprolu
2016-08-05 6:14 ` [PATCH 2/2] powerpc/pseries: Dynamically increase RMA size Sukadev Bhattiprolu
2016-08-05 13:28 ` kbuild test robot
2016-08-05 18:30 ` Sukadev Bhattiprolu
2016-08-05 19:04 ` Paul Clarke
2016-08-09 17:11 ` Sukadev Bhattiprolu
2017-02-01 5:37 ` Michael Ellerman
2017-02-01 17:49 ` Thiago Jung Bauermann [this message]
2017-02-01 18:11 ` Sukadev Bhattiprolu
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