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Groups > linux.kernel > #1599507
| From | Michal Hocko <mhocko@kernel.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: WTH is going on with memory hotplug sysf interface (was: Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks) |
| Date | 2017-03-13 16:20 +0100 |
| Message-ID | <tkzVo-2n4-31@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <ti2qS-1v4-17@gated-at.bofh.it> <timIX-7Bl-37@gated-at.bofh.it> <tj5PJ-5jo-23@gated-at.bofh.it> <tjtfj-4NB-5@gated-at.bofh.it> <tjv7r-66F-9@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Let's add Andi
On Fri 10-03-17 16:53:33, Michal Hocko wrote:
> On Fri 10-03-17 14:58:07, Michal Hocko wrote:
> [...]
> > This would explain why onlining from the last block actually works but
> > to me this sounds like a completely crappy behavior. All we need to
> > guarantee AFAICS is that Normal and Movable zones do not overlap. I
> > believe there is even no real requirement about ordering of the physical
> > memory in Normal vs. Movable zones as long as they do not overlap. But
> > let's keep it simple for the start and always enforce the current status
> > quo that Normal zone is physically preceeding Movable zone.
> > Can somebody explain why we cannot have a simple rule for Normal vs.
> > Movable which would be:
> > - block [pfn, pfn+block_size] can be Normal if
> > !zone_populated(MOVABLE) || pfn+block_size < ZONE_MOVABLE->zone_start_pfn
> > - block [pfn, pfn+block_size] can be Movable if
> > !zone_populated(NORMAL) || ZONE_NORMAL->zone_end_pfn < pfn
>
> OK, so while I was playing with this setup some more I probably got why
> this is done this way. All new memblocks are added to the zone Normal
> where they are accounted as spanned but not present. When we do
> online_movable we just cut from the end of the Normal zone and move it
> to Movable zone. This sounds really awkward. What was the reason to go
> this way? Why cannot we simply add those pages to the zone at the online
> time?
Answering to myself. So the reason seems to be 9d99aaa31f59 ("[PATCH]
x86_64: Support memory hotadd without sparsemem") which is no longer
true because
config MEMORY_HOTPLUG
bool "Allow for memory hot-add"
depends on SPARSEMEM || X86_64_ACPI_NUMA
depends on ARCH_ENABLE_MEMORY_HOTPLUG
depends on COMPILE_TEST || !KASAN
so it is either SPARSEMEM or X86_64_ACPI_NUMA that would have to be enabled.
config X86_64_ACPI_NUMA
def_bool y
prompt "ACPI NUMA detection"
depends on X86_64 && NUMA && ACPI && PCI
select ACPI_NUMA
But I do not see any way how to enable anything but SPARSEMEM for x86_64
choice
prompt "Memory model"
depends on SELECT_MEMORY_MODEL
default DISCONTIGMEM_MANUAL if ARCH_DISCONTIGMEM_DEFAULT
default SPARSEMEM_MANUAL if ARCH_SPARSEMEM_DEFAULT
default FLATMEM_MANUAL
ARCH_SPARSEMEM_DEFAULT is 32b only
config ARCH_DISCONTIGMEM_DEFAULT
def_bool y
depends on NUMA && X86_32
and ARCH_SPARSEMEM_DEFAULT is enabeld on 64b. So I guess whatever was
the reason to add this code back in 2006 is not true anymore. So I am
really wondering. Do we absolutely need to assign pages which are not
onlined yet to the ZONE_NORMAL unconditionally? Why cannot we put them
out of any zone and wait for memory online operation to put them where
requested?
--
Michal Hocko
SUSE Labs
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Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Igor Mammedov <imammedo@redhat.com> - 2017-03-02 15:00 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Michal Hocko <mhocko@kernel.org> - 2017-03-02 16:10 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Igor Mammedov <imammedo@redhat.com> - 2017-03-02 18:20 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Michal Hocko <mhocko@kernel.org> - 2017-03-03 10:10 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Igor Mammedov <imammedo@redhat.com> - 2017-03-03 18:40 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Michal Hocko <mhocko@kernel.org> - 2017-03-06 16:10 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Igor Mammedov <imammedo@redhat.com> - 2017-03-07 13:50 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Michal Hocko <mhocko@kernel.org> - 2017-03-09 14:00 +0100
WTH is going on with memory hotplug sysf interface (was: Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks) Michal Hocko <mhocko@kernel.org> - 2017-03-10 15:00 +0100
Re: WTH is going on with memory hotplug sysf interface (was: Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks) Michal Hocko <mhocko@kernel.org> - 2017-03-10 17:00 +0100
Re: WTH is going on with memory hotplug sysf interface (was: Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks) Reza Arbab <arbab@linux.vnet.ibm.com> - 2017-03-10 20:10 +0100
Re: WTH is going on with memory hotplug sysf interface (was: Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks) Michal Hocko <mhocko@kernel.org> - 2017-03-13 10:30 +0100
Re: WTH is going on with memory hotplug sysf interface (was: Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks) Reza Arbab <arbab@linux.vnet.ibm.com> - 2017-03-13 16:00 +0100
Re: WTH is going on with memory hotplug sysf interface (was: Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks) Andrea Arcangeli <aarcange@redhat.com> - 2017-03-14 20:40 +0100
Re: WTH is going on with memory hotplug sysf interface (was: Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks) Michal Hocko <mhocko@kernel.org> - 2017-03-15 09:00 +0100
Re: WTH is going on with memory hotplug sysf interface (was: Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks) Michal Hocko <mhocko@kernel.org> - 2017-03-13 16:20 +0100
Re: WTH is going on with memory hotplug sysf interface (was: Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks) Andi Kleen <ak@linux.intel.com> - 2017-03-14 00:20 +0100
Re: WTH is going on with memory hotplug sysf interface Yasuaki Ishimatsu <yasu.isimatu@gmail.com> - 2017-03-10 18:40 +0100
Re: WTH is going on with memory hotplug sysf interface Michal Hocko <mhocko@kernel.org> - 2017-03-13 10:30 +0100
Re: WTH is going on with memory hotplug sysf interface YASUAKI ISHIMATSU <yasu.isimatu@gmail.com> - 2017-03-14 17:10 +0100
Re: WTH is going on with memory hotplug sysf interface Michal Hocko <mhocko@kernel.org> - 2017-03-14 17:30 +0100
Re: WTH is going on with memory hotplug sysf interface (was: Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks) Igor Mammedov <imammedo@redhat.com> - 2017-03-13 11:40 +0100
Re: WTH is going on with memory hotplug sysf interface (was: Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks) Michal Hocko <mhocko@kernel.org> - 2017-03-13 11:50 +0100
Re: WTH is going on with memory hotplug sysf interface (was: Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks) Igor Mammedov <imammedo@redhat.com> - 2017-03-13 15:00 +0100
Re: WTH is going on with memory hotplug sysf interface (was: Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks) Michal Hocko <mhocko@kernel.org> - 2017-03-13 15:40 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Igor Mammedov <imammedo@redhat.com> - 2017-03-13 12:00 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Michal Hocko <mhocko@kernel.org> - 2017-03-13 13:30 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-03-13 14:00 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Michal Hocko <mhocko@kernel.org> - 2017-03-13 14:20 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-03-13 14:50 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Michal Hocko <mhocko@kernel.org> - 2017-03-13 15:40 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-03-13 16:20 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Igor Mammedov <imammedo@redhat.com> - 2017-03-14 14:30 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Michal Hocko <mhocko@kernel.org> - 2017-03-15 09:00 +0100
Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks Daniel Kiper <daniel.kiper@oracle.com> - 2017-03-10 23:10 +0100
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