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From: David Hildenbrand <david@redhat.com>
To: Michael Ellerman <mpe@ellerman.id.au>, linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>,
	Marek Kedzierski <mkedzier@redhat.com>,
	Hui Zhu <teawater@gmail.com>,
	Pankaj Gupta <pankaj.gupta.linux@gmail.com>,
	Wei Yang <richard.weiyang@linux.alibaba.com>,
	Oscar Salvador <osalvador@suse.de>,
	Michal Hocko <mhocko@kernel.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Vlastimil Babka <vbabka@suse.cz>, Mike Rapoport <rppt@kernel.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Len Brown <lenb@kernel.org>,
	Pavel Tatashin <pasha.tatashin@soleen.com>,
	virtualization@lists.linux-foundation.org, linux-mm@kvack.org,
	linux-acpi@vger.kernel.org,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Nathan Lynch <nathanl@linux.ibm.com>,
	Laurent Dufour <ldufour@linux.ibm.com>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	Scott Cheloha <cheloha@linux.ibm.com>,
	Anton Blanchard <anton@ozlabs.org>,
	linuxppc-dev@lists.ozlabs.org, nvdimm@lists.linux.dev
Subject: Re: [PATCH v1 05/12] mm/memory_hotplug: remove nid parameter from remove_memory() and friends
Date: Tue, 8 Jun 2021 13:18:55 +0200	[thread overview]
Message-ID: <7463b3ed-07d3-7157-629d-a85a3ff558d6@redhat.com> (raw)
In-Reply-To: <87y2bkehky.fsf@mpe.ellerman.id.au>

On 08.06.21 13:11, Michael Ellerman wrote:
> David Hildenbrand <david@redhat.com> writes:
>> There is only a single user remaining. We can simply try to offline all
>> online nodes - which is fast, because we usually span pages and can skip
>> such nodes right away.
> 
> That makes me slightly nervous, because our big powerpc boxes tend to
> trip on these scaling issues before others.
> 
> But the spanned pages check is just:
> 
> void try_offline_node(int nid)
> {
> 	pg_data_t *pgdat = NODE_DATA(nid);
>          ...
> 	if (pgdat->node_spanned_pages)
> 		return;
> 
> So I guess that's pretty cheap, and it's only O(nodes), which should
> never get that big.

Exactly. And if it does turn out to be a problem, we can walk all memory 
blocks before removing them, collecting the nid(s).

-- 
Thanks,

David / dhildenb


  reply	other threads:[~2021-06-08 11:19 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-07 19:54 [PATCH v1 00/12] mm/memory_hotplug: "auto-movable" online policy and memory groups David Hildenbrand
2021-06-07 19:54 ` [PATCH v1 01/12] mm/memory_hotplug: use "unsigned long" for PFN in zone_for_pfn_range() David Hildenbrand
2021-06-07 19:54 ` [PATCH v1 02/12] mm: track present early pages per zone David Hildenbrand
2021-06-07 19:54 ` [PATCH v1 03/12] mm/memory_hotplug: introduce "auto-movable" online policy David Hildenbrand
2021-06-07 19:54 ` [PATCH v1 04/12] mm/memory_hotplug: remove nid parameter from arch_remove_memory() David Hildenbrand
2021-06-08  8:32   ` Catalin Marinas
2021-06-08 10:50   ` Michael Ellerman
2021-06-09  5:51   ` Heiko Carstens
2021-06-07 19:54 ` [PATCH v1 05/12] mm/memory_hotplug: remove nid parameter from remove_memory() and friends David Hildenbrand
2021-06-08 11:11   ` Michael Ellerman
2021-06-08 11:18     ` David Hildenbrand [this message]
2021-06-09 10:05       ` David Hildenbrand
2021-06-07 19:54 ` [PATCH v1 06/12] drivers/base/memory: "memory groups" to logically group memory blocks David Hildenbrand
2021-06-07 19:54 ` [PATCH v1 07/12] mm/memory_hotplug: track present pages in memory groups David Hildenbrand
2021-06-07 19:54 ` [PATCH v1 08/12] ACPI: memhotplug: memory resources cannot be enabled yet David Hildenbrand
2021-06-08 12:20   ` Rafael J. Wysocki
2021-06-07 19:54 ` [PATCH v1 09/12] ACPI: memhotplug: use a single static memory group for a single memory device David Hildenbrand
2021-06-08 12:20   ` Rafael J. Wysocki
2021-06-07 19:54 ` [PATCH v1 10/12] virtio-mem: use a single dynamic memory group for a single virtio-mem device David Hildenbrand
2021-06-07 19:54 ` [PATCH v1 11/12] mm/memory_hotplug: memory group aware "auto-movable" online policy David Hildenbrand
2021-06-07 19:54 ` [PATCH v1 12/12] mm/memory_hotplug: improved dynamic " David Hildenbrand
2021-06-08  9:42 ` [PATCH v1 00/12] mm/memory_hotplug: "auto-movable" online policy and memory groups Oscar Salvador
2021-06-08 10:12   ` David Hildenbrand

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