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[2003:cb:c743:5100:93b1:f654:ad11:cd81]) by smtp.gmail.com with ESMTPSA id fm19-20020a05600c0c1300b00405959bbf4fsm2087849wmb.19.2023.10.17.07.49.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 17 Oct 2023 07:49:39 -0700 (PDT) Message-ID: Date: Tue, 17 Oct 2023 16:49:38 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 2/3] mm/memory_hotplug: split memmap_on_memory requests across memblocks To: Vishal Verma , Andrew Morton , Oscar Salvador , Dan Williams , Dave Jiang Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org, Huang Ying , Dave Hansen , "Aneesh Kumar K.V" , Michal Hocko , Jonathan Cameron , Jeff Moyer References: <20231016-vv-kmem_memmap-v6-0-078f0d3c0371@intel.com> <20231016-vv-kmem_memmap-v6-2-078f0d3c0371@intel.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <20231016-vv-kmem_memmap-v6-2-078f0d3c0371@intel.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: b6imngnybf6kamixso7etcxzsfmpf6tn X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: C410920016 X-Rspam-User: X-HE-Tag: 1697554188-969037 X-HE-Meta: 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 dOVLWuTQ 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 17.10.23 07:44, Vishal Verma wrote: > The MHP_MEMMAP_ON_MEMORY flag for hotplugged memory is restricted to > 'memblock_size' chunks of memory being added. Adding a larger span of > memory precludes memmap_on_memory semantics. > > For users of hotplug such as kmem, large amounts of memory might get > added from the CXL subsystem. In some cases, this amount may exceed the > available 'main memory' to store the memmap for the memory being added. > In this case, it is useful to have a way to place the memmap on the > memory being added, even if it means splitting the addition into > memblock-sized chunks. > > Change add_memory_resource() to loop over memblock-sized chunks of > memory if caller requested memmap_on_memory, and if other conditions for > it are met. Teach try_remove_memory() to also expect that a memory > range being removed might have been split up into memblock sized chunks, > and to loop through those as needed. > > This does preclude being able to use PUD mappings in the direct map; a > proposal to how this could be optimized in the future is laid out > here[1]. > > [1]: https://lore.kernel.org/linux-mm/b6753402-2de9-25b2-36e9-eacd49752b19@redhat.com/ > > Cc: Andrew Morton > Cc: David Hildenbrand > Cc: Michal Hocko > Cc: Oscar Salvador > Cc: Dan Williams > Cc: Dave Jiang > Cc: Dave Hansen > Cc: Huang Ying > Suggested-by: David Hildenbrand > Reviewed-by: Dan Williams > Signed-off-by: Vishal Verma > --- > mm/memory_hotplug.c | 214 ++++++++++++++++++++++++++++++++++++---------------- > 1 file changed, 148 insertions(+), 66 deletions(-) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index 6be7de9efa55..83e5ec377aad 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -1380,6 +1380,43 @@ static bool mhp_supports_memmap_on_memory(unsigned long size) > return arch_supports_memmap_on_memory(vmemmap_size); > } > > +static int add_memory_create_devices(int nid, struct memory_group *group, > + u64 start, u64 size, mhp_t mhp_flags) > +{ > + struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) }; > + struct vmem_altmap mhp_altmap = { > + .base_pfn = PHYS_PFN(start), > + .end_pfn = PHYS_PFN(start + size - 1), > + }; > + int ret; > + > + if ((mhp_flags & MHP_MEMMAP_ON_MEMORY)) { > + mhp_altmap.free = memory_block_memmap_on_memory_pages(); > + params.altmap = kmemdup(&mhp_altmap, sizeof(struct vmem_altmap), > + GFP_KERNEL); > + if (!params.altmap) > + return -ENOMEM; > + } > + > + /* call arch's memory hotadd */ > + ret = arch_add_memory(nid, start, size, ¶ms); > + if (ret < 0) > + goto error; > + > + /* create memory block devices after memory was added */ > + ret = create_memory_block_devices(start, size, params.altmap, group); > + if (ret) > + goto err_bdev; > + > + return 0; > + > +err_bdev: > + arch_remove_memory(start, size, NULL); > +error: > + kfree(params.altmap); > + return ret; > +} > + > /* > * NOTE: The caller must call lock_device_hotplug() to serialize hotplug > * and online/offline operations (triggered e.g. by sysfs). > @@ -1388,14 +1425,10 @@ static bool mhp_supports_memmap_on_memory(unsigned long size) > */ > int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) > { > - struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) }; > + unsigned long memblock_size = memory_block_size_bytes(); > enum memblock_flags memblock_flags = MEMBLOCK_NONE; > - struct vmem_altmap mhp_altmap = { > - .base_pfn = PHYS_PFN(res->start), > - .end_pfn = PHYS_PFN(res->end), > - }; > struct memory_group *group = NULL; > - u64 start, size; > + u64 start, size, cur_start; > bool new_node = false; > int ret; > > @@ -1436,28 +1469,21 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) > /* > * Self hosted memmap array > */ > - if (mhp_flags & MHP_MEMMAP_ON_MEMORY) { > - if (mhp_supports_memmap_on_memory(size)) { > - mhp_altmap.free = memory_block_memmap_on_memory_pages(); > - params.altmap = kmemdup(&mhp_altmap, > - sizeof(struct vmem_altmap), > - GFP_KERNEL); > - if (!params.altmap) > + if ((mhp_flags & MHP_MEMMAP_ON_MEMORY) && > + mhp_supports_memmap_on_memory(memblock_size)) { > + for (cur_start = start; cur_start < start + size; > + cur_start += memblock_size) { > + ret = add_memory_create_devices(nid, group, cur_start, > + memblock_size, > + mhp_flags); Just like on the removal part, that function doesn't make any sense to be called with altmap and a bigger range. Maybe better also move that loop into a function called "create_altmap_and_memory_blocks()" , to be the opposite of "remove_memory_blocks_and_altmaps()". Then you can keep the existing !altmap code here in the "else" case. Again, similar to the removal code below. > + if (ret) > goto error; > } > - /* fallback to not using altmap */ > - } > - > - /* call arch's memory hotadd */ > - ret = arch_add_memory(nid, start, size, ¶ms); > - if (ret < 0) > - goto error_free; > - > - /* create memory block devices after memory was added */ > - ret = create_memory_block_devices(start, size, params.altmap, group); > - if (ret) { > - arch_remove_memory(start, size, NULL); > - goto error_free; > + } else { > + ret = add_memory_create_devices(nid, group, start, size, > + mhp_flags); > + if (ret) > + goto error; > } > > if (new_node) { > @@ -1494,8 +1520,6 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) > walk_memory_blocks(start, size, NULL, online_memory_block); > > return ret; > -error_free: > - kfree(params.altmap); > error: > if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) > memblock_remove(start, size); > @@ -2076,6 +2100,23 @@ static int test_has_altmap_cb(struct memory_block *mem, void *arg) > return 0; > } [...] > + > +static int memblocks_have_altmaps(u64 start, u64 size) > +{ > + struct memory_range_altmap_info altmap_info = { > + .num_memblocks = 0, > + .num_altmaps = 0 > + }; You can get the number of memblocks simply by "size / memory_block_size_bytes()". So you can avoid the "struct" and just pass an int. > + > + if (!mhp_memmap_on_memory()) > + return 0; > + > + walk_memory_blocks(start, size, &altmap_info, > + count_memory_range_altmaps_cb); > + > + if (!altmap_info.num_altmaps) > + return 0; > + > + if (altmap_info.num_memblocks != altmap_info.num_altmaps) { > + WARN_ONCE(1, "Not all memblocks in range have altmaps"); > + return -EINVAL; > + } > + > + return 1; > +} > + > +static int __ref try_remove_memory(u64 start, u64 size) > +{ > + int rc, nid = NUMA_NO_NODE; > > BUG_ON(check_hotplug_memory_range(start, size)); > > @@ -2167,45 +2272,21 @@ static int __ref try_remove_memory(u64 start, u64 size) > if (rc) > return rc; > > - /* > - * We only support removing memory added with MHP_MEMMAP_ON_MEMORY in > - * the same granularity it was added - a single memory block. > - */ > - if (mhp_memmap_on_memory()) { > - rc = walk_memory_blocks(start, size, &mem, test_has_altmap_cb); > - if (rc) { > - if (size != memory_block_size_bytes()) { > - pr_warn("Refuse to remove %#llx - %#llx," > - "wrong granularity\n", > - start, start + size); > - return -EINVAL; > - } > - altmap = mem->altmap; > - /* > - * Mark altmap NULL so that we can add a debug > - * check on memblock free. > - */ > - mem->altmap = NULL; > - } > - } > - > /* remove memmap entry */ > firmware_map_remove(start, start + size, "System RAM"); > > - /* > - * Memory block device removal under the device_hotplug_lock is > - * a barrier against racing online attempts. > - */ Maybe move that comment into the else branch and not into remove_memory_blocks_and_altmaps > - remove_memory_block_devices(start, size); > - > mem_hotplug_begin(); > > - arch_remove_memory(start, size, altmap); > - > - /* Verify that all vmemmap pages have actually been freed. */ > - if (altmap) { > - WARN(altmap->alloc, "Altmap not fully unmapped"); > - kfree(altmap); > + rc = memblocks_have_altmaps(start, size); Don't use the term memblocks here, to not confuse it with the memblock allocator. "memory blocks" or "memory block devices". it's complicated. > + if (rc < 0) { > + goto err; > + } else if (rc == 0) { > + /* no altmaps, do the removal directly */ > + remove_memory_block_devices(start, size); > + arch_remove_memory(start, size, NULL); > + } else { > + /* all memblocks in the range have altmaps */ > + remove_memory_blocks_and_altmaps(start, size); > } > > if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) { > @@ -2218,8 +2299,9 @@ static int __ref try_remove_memory(u64 start, u64 size) > if (nid != NUMA_NO_NODE) > try_offline_node(nid); > > +err: > mem_hotplug_done(); > - return 0; > + return (rc < 0 ? rc : 0); > } > > /** > -- Cheers, David / dhildenb