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Re: WTH is going on with memory hotplug sysf interface (was: Re: [RFC PATCH] mm, hotplug: get rid of auto_online_blocks)

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On Fri 10-03-17 13:00:37, Reza Arbab wrote:
> On Fri, Mar 10, 2017 at 04:53:33PM +0100, Michal Hocko wrote:
> >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.
> 
> It's not always zone Normal. See zone_for_memory(). This leads to a
> workaround for having to do online_movable in descending block order.
> Instead of this:
> 
> 1. probe block 34, probe block 33, probe block 32, ...
> 2. online_movable 34, online_movable 33, online_movable 32, ...
> 
> you can online_movable the first block before adding the rest:

I do I enforce that behavior when the probe happens automagically?

> 1. probe block 32, online_movable 32
> 2. probe block 33, probe block 34, ...
> 	- zone_for_memory() will cause these to start Movable
> 3. online 33, online 34, ...
> 	- they're already in Movable, so online_movable is equivalentr
> 
> I agree with your general sentiment that this stuff is very nonintuitive.

My criterion for nonintuitive is probably different because I would call
this _completely_unusable_. Sorry for being so loud about this but the
more I look into this area the more WTF code I see. This has seen close
to zero review and seems to be building up more single usecase code on
top of previous. We need to change this, seriously!
-- 
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) 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 (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 Daniel Kiper <daniel.kiper@oracle.com> - 2017-03-10 23:10 +0100

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