From: David Hildenbrand <david@redhat.com>
To: Wei Yang <richard.weiyang@gmail.com>
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>,
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>,
Ingo Molnar <mingo@kernel.org>,
Andrew Banman <andrew.banman@hpe.com>,
Oscar Salvador <osalvador@suse.de>,
Michal Hocko <mhocko@suse.com>,
Pavel Tatashin <pasha.tatashin@soleen.com>, Qian Cai <cai@lca.pw>,
Arun KS <arunks@codeaurora.org>,
Mathieu Malaterre <malat@debian.org>
Subject: Re: [PATCH v3 07/11] mm/memory_hotplug: Create memory block devices after arch_add_memory()
Date: Wed, 5 Jun 2019 10:58:26 +0200 [thread overview]
Message-ID: <f6523d67-cac9-1189-884a-67b6829320ba@redhat.com> (raw)
In-Reply-To: <20190604214234.ltwtkcdoju2gxisx@master>
>> /*
>> * For now, we have a linear search to go find the appropriate
>> * memory_block corresponding to a particular phys_index. If
>> @@ -658,6 +670,11 @@ static int init_memory_block(struct memory_block **memory, int block_id,
>> unsigned long start_pfn;
>> int ret = 0;
>>
>> + mem = find_memory_block_by_id(block_id, NULL);
>> + if (mem) {
>> + put_device(&mem->dev);
>> + return -EEXIST;
>> + }
>
> find_memory_block_by_id() is not that close to the main idea in this patch.
> Would it be better to split this part?
I played with that but didn't like the temporary results (e.g. having to
export find_memory_block_by_id()). I'll stick to this for now.
>
>> mem = kzalloc(sizeof(*mem), GFP_KERNEL);
>> if (!mem)
>> return -ENOMEM;
>> @@ -699,44 +716,53 @@ static int add_memory_block(int base_section_nr)
>> return 0;
>> }
>>
>> +static void unregister_memory(struct memory_block *memory)
>> +{
>> + if (WARN_ON_ONCE(memory->dev.bus != &memory_subsys))
>> + return;
>> +
>> + /* drop the ref. we got via find_memory_block() */
>> + put_device(&memory->dev);
>> + device_unregister(&memory->dev);
>> +}
>> +
>> /*
>> - * need an interface for the VM to add new memory regions,
>> - * but without onlining it.
>> + * Create memory block devices for the given memory area. Start and size
>> + * have to be aligned to memory block granularity. Memory block devices
>> + * will be initialized as offline.
>> */
>> -int hotplug_memory_register(int nid, struct mem_section *section)
>> +int create_memory_block_devices(unsigned long start, unsigned long size)
>> {
>> - int block_id = base_memory_block_id(__section_nr(section));
>> - int ret = 0;
>> + const int start_block_id = pfn_to_block_id(PFN_DOWN(start));
>> + int end_block_id = pfn_to_block_id(PFN_DOWN(start + size));
>> struct memory_block *mem;
>> + unsigned long block_id;
>> + int ret = 0;
>>
>> - mutex_lock(&mem_sysfs_mutex);
>> + if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) ||
>> + !IS_ALIGNED(size, memory_block_size_bytes())))
>> + return -EINVAL;
>>
>> - mem = find_memory_block(section);
>> - if (mem) {
>> - mem->section_count++;
>> - put_device(&mem->dev);
>> - } else {
>> + mutex_lock(&mem_sysfs_mutex);
>> + for (block_id = start_block_id; block_id != end_block_id; block_id++) {
>> ret = init_memory_block(&mem, block_id, MEM_OFFLINE);
>> if (ret)
>> - goto out;
>> - mem->section_count++;
>> + break;
>> + mem->section_count = sections_per_block;
>> + }
>> + if (ret) {
>> + end_block_id = block_id;
>> + for (block_id = start_block_id; block_id != end_block_id;
>> + block_id++) {
>> + mem = find_memory_block_by_id(block_id, NULL);
>> + mem->section_count = 0;
>> + unregister_memory(mem);
>> + }
>> }
>
> Would it be better to do this in reverse order?
>
> And unregister_memory() would free mem, so it is still necessary to set
> section_count to 0?
1. I kept the existing behavior (setting it to 0) for now. I am planning
to eventually remove the section count completely (it could be
beneficial to detect removing of partially populated memory blocks).
2. Reverse order: We would have to start with "block_id - 1", I don't
like that better.
Thanks for having a look!
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2019-06-05 8:58 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 [this message]
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
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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