From: David Hildenbrand <david@redhat.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-s390@vger.kernel.org, linux-sh@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, akpm@linux-foundation.org,
Dan Williams <dan.j.williams@intel.com>,
Wei Yang <richard.weiyang@gmail.com>,
Igor Mammedov <imammedo@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
"mike.travis@hpe.com" <mike.travis@hpe.com>,
Andrew Banman <andrew.banman@hpe.com>,
Ingo Molnar <mingo@kernel.org>,
Alex Deucher <alexander.deucher@amd.com>,
"David S. Miller" <davem@davemloft.net>,
Mark Brown <broonie@kernel.org>,
Chris Wilson <chris@chris-wilson.co.uk>,
Oscar Salvador <osalvador@suse.de>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>,
Pavel Tatashin <pavel.tatashin@microsoft.com>,
Arun KS <arunks@codeaurora.org>,
Mathieu Malaterre <malat@debian.org>
Subject: Re: [PATCH v3 09/11] mm/memory_hotplug: Remove memory block devices before arch_remove_memory()
Date: Mon, 15 Jul 2019 12:58:22 +0200 [thread overview]
Message-ID: <54a2f873-374e-b132-ae0f-4924a7e332c0@redhat.com> (raw)
In-Reply-To: <20190701084129.GI6376@dhcp22.suse.cz>
On 01.07.19 10:41, Michal Hocko wrote:
> On Mon 27-05-19 13:11:50, David Hildenbrand wrote:
>> Let's factor out removing of memory block devices, which is only
>> necessary for memory added via add_memory() and friends that created
>> memory block devices. Remove the devices before calling
>> arch_remove_memory().
>>
>> This finishes factoring out memory block device handling from
>> arch_add_memory() and arch_remove_memory().
>
> OK, this makes sense again. Just a nit. Calling find_memory_block_by_id
> for each memory block looks a bit suboptimal, especially when we are
> removing consequent physical memblocks. I have to confess that I do not
> know how expensive is the search and I also expect that there won't be
> that many memblocks in the removed range anyway as large setups have
> large memblocks.
>
The devices are not allocated sequentially, so there is no easy way to
look them up.
There is a comment for find_memory_block():
"For now, we have a linear search to go find the appropriate
memory_block corresponding to a particular phys_index. If this gets to
be a real problem, we can always use a radix tree or something here."
So if this becomes a problem, we need a separate data structure to speed
up the lookup. (IOW, this was already the same in the old code)
Thanks!
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2019-07-15 10:58 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-27 11:11 [PATCH v3 00/11] mm/memory_hotplug: Factor out memory block devicehandling David Hildenbrand
2019-05-27 11:11 ` [PATCH v3 01/11] mm/memory_hotplug: Simplify and fix check_hotplug_memory_range() David Hildenbrand
2019-05-30 17:53 ` Pavel Tatashin
2019-06-10 16:46 ` Oscar Salvador
2019-07-01 7:42 ` Michal Hocko
2019-05-27 11:11 ` [PATCH v3 02/11] s390x/mm: Fail when an altmap is used for arch_add_memory() David Hildenbrand
2019-06-10 17:07 ` Oscar Salvador
2019-07-01 7:43 ` Michal Hocko
2019-07-01 12:46 ` Michal Hocko
2019-07-15 10:51 ` David Hildenbrand
2019-07-19 6:45 ` Michal Hocko
2019-05-27 11:11 ` [PATCH v3 03/11] s390x/mm: Implement arch_remove_memory() David Hildenbrand
2019-07-01 7:45 ` Michal Hocko
2019-07-01 12:47 ` Michal Hocko
2019-07-15 10:45 ` David Hildenbrand
2019-05-27 11:11 ` [PATCH v3 04/11] arm64/mm: Add temporary arch_remove_memory() implementation David Hildenbrand
2019-06-03 21:41 ` Wei Yang
2019-06-04 6:56 ` David Hildenbrand
2019-06-04 17:36 ` Robin Murphy
2019-06-04 17:51 ` David Hildenbrand
2019-07-01 12:48 ` Michal Hocko
2019-05-27 11:11 ` [PATCH v3 05/11] drivers/base/memory: Pass a block_id to init_memory_block() David Hildenbrand
2019-06-03 21:49 ` Wei Yang
2019-06-04 6:56 ` David Hildenbrand
2019-07-01 7:56 ` Michal Hocko
2019-05-27 11:11 ` [PATCH v3 06/11] mm/memory_hotplug: Allow arch_remove_pages() without CONFIG_MEMORY_HOTREMOVE David Hildenbrand
2019-05-30 17:56 ` Pavel Tatashin
2019-06-03 22:15 ` Wei Yang
2019-06-04 6:59 ` David Hildenbrand
2019-06-04 8:31 ` Wei Yang
2019-06-04 9:00 ` David Hildenbrand
2019-07-01 8:01 ` Michal Hocko
2019-07-01 12:51 ` Michal Hocko
2019-07-15 10:54 ` David Hildenbrand
2019-07-19 6:06 ` Michal Hocko
2019-05-27 11:11 ` [PATCH v3 07/11] mm/memory_hotplug: Create memory block devices after arch_add_memory() David Hildenbrand
2019-05-30 21:07 ` Pavel Tatashin
2019-06-04 21:42 ` Wei Yang
2019-06-05 8:58 ` David Hildenbrand
2019-06-05 10:58 ` David Hildenbrand
2019-06-05 21:22 ` Wei Yang
2019-06-05 21:50 ` David Hildenbrand
2019-07-01 8:14 ` Michal Hocko
2019-05-27 11:11 ` [PATCH v3 08/11] mm/memory_hotplug: Drop MHP_MEMBLOCK_API David Hildenbrand
2019-06-04 21:47 ` Wei Yang
2019-07-01 8:15 ` Michal Hocko
2019-05-27 11:11 ` [PATCH v3 09/11] mm/memory_hotplug: Remove memory block devices before arch_remove_memory() David Hildenbrand
2019-06-04 22:07 ` Wei Yang
2019-06-05 9:00 ` David Hildenbrand
2019-07-01 8:41 ` Michal Hocko
2019-07-15 10:58 ` David Hildenbrand [this message]
2019-05-27 11:11 ` [PATCH v3 10/11] mm/memory_hotplug: Make unregister_memory_block_under_nodes() never fail David Hildenbrand
2019-06-05 21:21 ` Wei Yang
2019-06-10 16:56 ` Oscar Salvador
2019-07-01 8:51 ` Michal Hocko
2019-07-01 9:36 ` Oscar Salvador
2019-07-01 10:27 ` Michal Hocko
2019-07-15 11:10 ` David Hildenbrand
2019-07-16 8:46 ` Oscar Salvador
2019-07-16 11:08 ` David Hildenbrand
2019-07-16 11:09 ` David Hildenbrand
2019-07-19 6:05 ` Michal Hocko
2019-05-27 11:11 ` [PATCH v3 11/11] mm/memory_hotplug: Remove "zone" parameter from sparse_remove_one_section David Hildenbrand
2019-06-05 21:21 ` Wei Yang
2019-06-10 16:58 ` Oscar Salvador
2019-07-01 8:52 ` Michal Hocko
2019-06-03 21:21 ` [PATCH v3 00/11] mm/memory_hotplug: Factor out memory block devicehandling Wei Yang
2019-06-03 21:40 ` David Hildenbrand
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