From: Michal Hocko <mhocko@suse.com>
To: Oscar Salvador <osalvador@suse.de>
Cc: Laurent Dufour <ldufour@linux.ibm.com>,
akpm@linux-foundation.org, David Hildenbrand <david@redhat.com>,
rafael@kernel.org, nathanl@linux.ibm.com, cheloha@linux.ibm.com,
stable@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: don't rely on system state to detect hot-plug operations
Date: Thu, 10 Sep 2020 14:47:55 +0200 [thread overview]
Message-ID: <20200910124755.GG28354@dhcp22.suse.cz> (raw)
In-Reply-To: <20200910120343.GA6635@linux>
On Thu 10-09-20 14:03:48, Oscar Salvador wrote:
> On Thu, Sep 10, 2020 at 01:35:32PM +0200, Laurent Dufour wrote:
>
> > That points has been raised by David, quoting him here:
> >
> > > IIRC, ACPI can hotadd memory while SCHEDULING, this patch would break that.
> > >
> > > Ccing Oscar, I think he mentioned recently that this is the case with ACPI.
> >
> > Oscar told that he need to investigate further on that.
>
> I think my reply got lost.
>
> We can see acpi hotplugs during SYSTEM_SCHEDULING:
>
> $QEMU -enable-kvm -machine pc -smp 4,sockets=4,cores=1,threads=1 -cpu host -monitor pty \
> -m size=$MEM,slots=255,maxmem=4294967296k \
> -numa node,nodeid=0,cpus=0-3,mem=512 -numa node,nodeid=1,mem=512 \
> -object memory-backend-ram,id=memdimm0,size=134217728 -device pc-dimm,node=0,memdev=memdimm0,id=dimm0,slot=0 \
> -object memory-backend-ram,id=memdimm1,size=134217728 -device pc-dimm,node=0,memdev=memdimm1,id=dimm1,slot=1 \
> -object memory-backend-ram,id=memdimm2,size=134217728 -device pc-dimm,node=0,memdev=memdimm2,id=dimm2,slot=2 \
> -object memory-backend-ram,id=memdimm3,size=134217728 -device pc-dimm,node=0,memdev=memdimm3,id=dimm3,slot=3 \
> -object memory-backend-ram,id=memdimm4,size=134217728 -device pc-dimm,node=1,memdev=memdimm4,id=dimm4,slot=4 \
> -object memory-backend-ram,id=memdimm5,size=134217728 -device pc-dimm,node=1,memdev=memdimm5,id=dimm5,slot=5 \
> -object memory-backend-ram,id=memdimm6,size=134217728 -device pc-dimm,node=1,memdev=memdimm6,id=dimm6,slot=6 \
>
> kernel: [ 0.753643] __add_memory: nid: 0 start: 0100000000 - 0108000000 (size: 134217728)
> kernel: [ 0.756950] register_mem_sect_under_node: system_state= 1
>
> kernel: [ 0.760811] register_mem_sect_under_node+0x4f/0x230
> kernel: [ 0.760811] walk_memory_blocks+0x80/0xc0
> kernel: [ 0.760811] link_mem_sections+0x32/0x40
> kernel: [ 0.760811] add_memory_resource+0x148/0x250
> kernel: [ 0.760811] __add_memory+0x5b/0x90
> kernel: [ 0.760811] acpi_memory_device_add+0x130/0x300
> kernel: [ 0.760811] acpi_bus_attach+0x13c/0x1c0
> kernel: [ 0.760811] acpi_bus_attach+0x60/0x1c0
> kernel: [ 0.760811] acpi_bus_scan+0x33/0x70
> kernel: [ 0.760811] acpi_scan_init+0xea/0x21b
> kernel: [ 0.760811] acpi_init+0x2f1/0x33c
> kernel: [ 0.760811] do_one_initcall+0x46/0x1f4
Is there any actual usecase for a configuration like this? What is the
point to statically define additional memory like this when the same can
be achieved on the same command line?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2020-09-10 12:48 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <5cbd92e1-c00a-4253-0119-c872bfa0f2bc@redhat.com>
[not found] ` <20200908170835.85440-1-ldufour@linux.ibm.com>
[not found] ` <20200908173113.GB218801@kroah.com>
2020-09-09 6:56 ` Laurent Dufour
[not found] ` <cb05da3d-334b-4b72-88c1-f8ed6cfc91b7@redhat.com>
2020-09-09 8:26 ` Laurent Dufour
2020-09-09 8:31 ` David Hildenbrand
2020-09-09 9:35 ` Laurent Dufour
2020-09-09 7:40 ` Michal Hocko
2020-09-09 7:48 ` Laurent Dufour
2020-09-09 9:09 ` Michal Hocko
2020-09-09 9:21 ` Laurent Dufour
2020-09-09 9:24 ` David Hildenbrand
2020-09-09 9:32 ` Laurent Dufour
2020-09-09 12:30 ` Greg Kroah-Hartman
2020-09-09 12:32 ` David Hildenbrand
2020-09-09 12:36 ` Greg Kroah-Hartman
2020-09-09 12:45 ` Michal Hocko
2020-09-09 10:59 ` Michal Hocko
2020-09-09 16:07 ` Laurent Dufour
2020-09-10 7:23 ` Michal Hocko
2020-09-10 7:51 ` Laurent Dufour
2020-09-10 11:12 ` Michal Hocko
2020-09-10 11:35 ` Laurent Dufour
2020-09-10 12:00 ` David Hildenbrand
2020-09-10 12:36 ` Laurent Dufour
2020-09-10 12:38 ` David Hildenbrand
2020-09-10 12:01 ` Michal Hocko
2020-09-10 12:03 ` Oscar Salvador
2020-09-10 12:32 ` Laurent Dufour
2020-09-10 12:47 ` Michal Hocko [this message]
2020-09-10 12:48 ` Michal Hocko
2020-09-10 13:39 ` Oscar Salvador
2020-09-10 13:51 ` Michal Hocko
2020-09-10 14:40 ` Michal Hocko
2020-09-10 12:49 ` David Hildenbrand
2020-09-10 13:54 ` Michal Hocko
2020-09-10 13:57 ` David Hildenbrand
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