On Fri 24-08-18 00:03:25, Naoya Horiguchi wrote:
> (CCed related people)
Fixup Pavel email.
>
> Hi Mizuma-san,
>
> Thank you for the report.
> The mentioned patch was created based on feedbacks from reviewers/maintainers,
> so I'd like to hear from them about how we should handle the issue.
>
> And one note is that there is a follow-up patch for "x86/e820: put !E820_TYPE_RAM
> regions into memblock.reserved" which might be affected by your changes.
>
> > commit e181ae0c5db9544de9c53239eb22bc012ce75033
> > Author: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
> > Date: Sat Jul 14 09:15:07 2018 -0400
> >
> > mm: zero unavailable pages before memmap init
>
> Thanks,
> Naoya Horiguchi
>
> On Thu, Aug 23, 2018 at 02:25:12PM -0400, Masayoshi Mizuma wrote:
> > From: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>
> >
> > commit 124049decbb1 ("x86/e820: put !E820_TYPE_RAM regions into
> > memblock.reserved") breaks movable_node kernel option because it
> > changed the memory gap range to reserved memblock. So, the node
> > is marked as Normal zone even if the SRAT has Hot plaggable affinity.
> >
> > =====================================================================
> > kernel: BIOS-e820: [mem 0x0000180000000000-0x0000180fffffffff] usable
> > kernel: BIOS-e820: [mem 0x00001c0000000000-0x00001c0fffffffff] usable
> > ...
> > kernel: reserved[0x12]#011[0x0000181000000000-0x00001bffffffffff], 0x000003f000000000 bytes flags: 0x0
> > ...
> > kernel: ACPI: SRAT: Node 2 PXM 6 [mem 0x180000000000-0x1bffffffffff] hotplug
> > kernel: ACPI: SRAT: Node 3 PXM 7 [mem 0x1c0000000000-0x1fffffffffff] hotplug
> > ...
> > kernel: Movable zone start for each node
> > kernel: Node 3: 0x00001c0000000000
> > kernel: Early memory node ranges
> > ...
> > =====================================================================
> >
> > Naoya's v1 patch [*] fixes the original issue and this movable_node
> > issue doesn't occur.
> > Let's revert commit 124049decbb1 ("x86/e820: put !E820_TYPE_RAM
> > regions into memblock.reserved") and apply the v1 patch.
> >
> > [*] https://lkml.org/lkml/2018/6/13/27
> >
> > Signed-off-by: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>
> > ---
> > arch/x86/kernel/e820.c | 15 +++------------
> > 1 file changed, 3 insertions(+), 12 deletions(-)
> >
> > diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
> > index c88c23c658c1..d1f25c831447 100644
> > --- a/arch/x86/kernel/e820.c
> > +++ b/arch/x86/kernel/e820.c
> > @@ -1248,7 +1248,6 @@ void __init e820__memblock_setup(void)
> > {
> > int i;
> > u64 end;
> > - u64 addr = 0;
> >
> > /*
> > * The bootstrap memblock region count maximum is 128 entries
> > @@ -1265,21 +1264,13 @@ void __init e820__memblock_setup(void)
> > struct e820_entry *entry = &e820_table->entries[i];
> >
> > end = entry->addr + entry->size;
> > - if (addr < entry->addr)
> > - memblock_reserve(addr, entry->addr - addr);
> > - addr = end;
> > if (end != (resource_size_t)end)
> > continue;
> >
> > - /*
> > - * all !E820_TYPE_RAM ranges (including gap ranges) are put
> > - * into memblock.reserved to make sure that struct pages in
> > - * such regions are not left uninitialized after bootup.
> > - */
> > if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN)
> > - memblock_reserve(entry->addr, entry->size);
> > - else
> > - memblock_add(entry->addr, entry->size);
> > + continue;
> > +
> > + memblock_add(entry->addr, entry->size);
> > }
> >
> > /* Throw away partial pages: */
> > --
> > 2.18.0
> >
> >
--
Michal Hocko
SUSE Labs
