From: Ingo Molnar <mingo@kernel.org>
To: Masayoshi Mizuma <msys.mizuma@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Baoquan He <bhe@redhat.com>,
Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>,
linux-kernel@vger.kernel.org, mike.travis@hpe.com,
sivanich@hpe.com
Subject: Re: [PATCH v3 1/2] x86/mm: Add an option to change the padding used for the physical memory mapping
Date: Wed, 19 Sep 2018 14:17:20 +0200 [thread overview]
Message-ID: <20180919121720.GA47424@gmail.com> (raw)
In-Reply-To: <20180918133026.gzyix3oyrfcsrdcx@gabell>
* Masayoshi Mizuma <msys.mizuma@gmail.com> wrote:
> Ping...
> I would appreciate if someone could review it because this patch
> fixes the real memory hotplug issue...
Yeah, so I generally try to resist random new boot options that
work around real bugs, so please convince me that this patch
is the best option:
>
> On Tue, Sep 04, 2018 at 11:11:40AM -0400, Masayoshi Mizuma wrote:
> > From: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
> >
> > If each node of physical memory layout has huge space for hotplug,
> > the padding used for the physical memory mapping section is not enough.
> > For exapmle of the layout:
> > SRAT: Node 6 PXM 4 [mem 0x100000000000-0x13ffffffffff] hotplug
> > SRAT: Node 7 PXM 5 [mem 0x140000000000-0x17ffffffffff] hotplug
> > SRAT: Node 2 PXM 6 [mem 0x180000000000-0x1bffffffffff] hotplug
> > SRAT: Node 3 PXM 7 [mem 0x1c0000000000-0x1fffffffffff] hotplug
> >
> > We can increase the padding by CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING,
> > however, the needed padding size depends on the system environment.
> > The kernel option is better than changing the config.
> >
> > Change log from v2:
> > - Simplify the description. As Baoquan said, this is simillar SGI UV issue,
> > but a little different. Remove SGI UV description.
Could you please explain it a bit better where the higher padding requirement comes from?
'system environment' is very opaque.
Thanks,
Ingo
next prev parent reply other threads:[~2018-09-19 12:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-04 15:11 [PATCH v3 1/2] x86/mm: Add an option to change the padding used for the physical memory mapping Masayoshi Mizuma
2018-09-04 15:11 ` [PATCH v3 2/2] docs: kernel-parameters.txt: document rand_mem_physical_padding parameter Masayoshi Mizuma
2018-09-18 13:30 ` [PATCH v3 1/2] x86/mm: Add an option to change the padding used for the physical memory mapping Masayoshi Mizuma
2018-09-19 12:17 ` Ingo Molnar [this message]
2018-09-19 12:30 ` Thomas Gleixner
2018-09-19 12:48 ` Ingo Molnar
2018-09-19 14:10 ` Masayoshi Mizuma
2018-09-19 23:05 ` Travis, Mike
2018-09-20 16:26 ` Masayoshi Mizuma
2018-09-20 9:28 ` Thomas Gleixner
2018-09-20 16:28 ` Masayoshi Mizuma
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