Re: [PATCH] x86: numa: drop ZONE_ALIGN

Luiz Capitulino
2014-06-11T13:23:37Z

Yinghai, sorry for my late reply.

On Mon, 9 Jun 2014 15:13:41 -0700
Yinghai Lu <yinghai@kernel.org> wrote:

> On Mon, Jun 9, 2014 at 12:03 PM, Luiz Capitulino <lcapitulino@redhat.com> wrote:
> > On Sun, 8 Jun 2014 18:29:11 -0700
> > Yinghai Lu <yinghai@kernel.org> wrote:
> >
> >> On Sun, Jun 8, 2014 at 3:14 PM, Luiz Capitulino <lcapitulino@redhat.com> wrote:
> > [ 0.000000] e820: BIOS-provided physical RAM map:
> > [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
> > [ 0.000000] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
> > [ 0.000000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved
> > [ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x000000003ffeffff] usable
> > [ 0.000000] BIOS-e820: [mem 0x000000003fff0000-0x000000003fffefff] ACPI data
> > [ 0.000000] BIOS-e820: [mem 0x000000003ffff000-0x000000003fffffff] ACPI NVS
> > [ 0.000000] BIOS-e820: [mem 0x0000000040200000-0x00000000801fffff] usable
> ...
> > [ 0.000000] SRAT: PXM 0 -> APIC 0x00 -> Node 0
> > [ 0.000000] SRAT: PXM 0 -> APIC 0x01 -> Node 0
> > [ 0.000000] SRAT: PXM 1 -> APIC 0x02 -> Node 1
> > [ 0.000000] SRAT: PXM 1 -> APIC 0x03 -> Node 1
> > [ 0.000000] SRAT: Node 0 PXM 0 [mem 0x00000000-0x3fffffff]
> > [ 0.000000] SRAT: Node 1 PXM 1 [mem 0x40200000-0x801fffff]
> > [ 0.000000] Initmem setup node 0 [mem 0x00000000-0x3fffffff]
> > [ 0.000000] NODE_DATA [mem 0x3ffec000-0x3ffeffff]
> > [ 0.000000] Initmem setup node 1 [mem 0x40800000-0x801fffff]
> > [ 0.000000] NODE_DATA [mem 0x801fb000-0x801fefff]
>
> so node1 start is aligned to 8M from 2M
>
> node0: [0, 1G)
> node1: [1G+2M, 2G+2M)
>
> The zone should not cross the 8M boundary?

Yes, but the question is: why?

> In the case should we trim the memblock for numa to be 8M alignment ?

My current thinking, after discussing this with David, is to just page
align the memory range. This should fix the hyperv-triggered bug in 2.6.32
and seems to be the right thing for upstream too.