starfive-tech/linux.git/mm/memory_hotplug.c, branch visionfive_v1_5.13

mm/mempool: minor coding style tweaks

2021-05-05T18:27:27+00:00

Various coding style tweaks to various files under mm/ [daizhiyuan@phytium.com.cn: mm/swapfile: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614223624-16055-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/sparse: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614227288-19363-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/vmscan: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614227649-19853-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/compaction: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228218-20770-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/oom_kill: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228360-21168-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/shmem: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228504-21491-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/page_alloc: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228613-21754-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/filemap: minor coding style tweaks] Link: https://lkml.kernel.org/r/1614228936-22337-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/mlock: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613956588-2453-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/frontswap: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613962668-15045-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/vmalloc: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613963379-15988-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/memory_hotplug: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613971784-24878-1-git-send-email-daizhiyuan@phytium.com.cn [daizhiyuan@phytium.com.cn: mm/mempolicy: minor coding style tweaks] Link: https://lkml.kernel.org/r/1613972228-25501-1-git-send-email-daizhiyuan@phytium.com.cn Link: https://lkml.kernel.org/r/1614222374-13805-1-git-send-email-daizhiyuan@phytium.com.cn Signed-off-by: Zhiyuan Dai Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm,memory_hotplug: add kernel boot option to enable memmap_on_memory

2021-05-05T18:27:27+00:00

Self stored memmap leads to a sparse memory situation which is unsuitable for workloads that requires large contiguous memory chunks, so make this an opt-in which needs to be explicitly enabled. To control this, let memory_hotplug have its own memory space, as suggested by David, so we can add memory_hotplug.memmap_on_memory parameter. Link: https://lkml.kernel.org/r/20210421102701.25051-7-osalvador@suse.de Signed-off-by: Oscar Salvador Reviewed-by: David Hildenbrand Acked-by: Michal Hocko Cc: Anshuman Khandual Cc: Pavel Tatashin Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm,memory_hotplug: allocate memmap from the added memory range

2021-05-05T18:27:26+00:00

Physical memory hotadd has to allocate a memmap (struct page array) for the newly added memory section. Currently, alloc_pages_node() is used for those allocations. This has some disadvantages: a) an existing memory is consumed for that purpose (eg: ~2MB per 128MB memory section on x86_64) This can even lead to extreme cases where system goes OOM because the physically hotplugged memory depletes the available memory before it is onlined. b) if the whole node is movable then we have off-node struct pages which has performance drawbacks. c) It might be there are no PMD_ALIGNED chunks so memmap array gets populated with base pages. This can be improved when CONFIG_SPARSEMEM_VMEMMAP is enabled. Vmemap page tables can map arbitrary memory. That means that we can reserve a part of the physically hotadded memory to back vmemmap page tables. This implementation uses the beginning of the hotplugged memory for that purpose. There are some non-obviously things to consider though. Vmemmap pages are allocated/freed during the memory hotplug events (add_memory_resource(), try_remove_memory()) when the memory is added/removed. This means that the reserved physical range is not online although it is used. The most obvious side effect is that pfn_to_online_page() returns NULL for those pfns. The current design expects that this should be OK as the hotplugged memory is considered a garbage until it is onlined. For example hibernation wouldn't save the content of those vmmemmaps into the image so it wouldn't be restored on resume but this should be OK as there no real content to recover anyway while metadata is reachable from other data structures (e.g. vmemmap page tables). The reserved space is therefore (de)initialized during the {on,off}line events (mhp_{de}init_memmap_on_memory). That is done by extracting page allocator independent initialization from the regular onlining path. The primary reason to handle the reserved space outside of {on,off}line_pages is to make each initialization specific to the purpose rather than special case them in a single function. As per above, the functions that are introduced are: - mhp_init_memmap_on_memory: Initializes vmemmap pages by calling move_pfn_range_to_zone(), calls kasan_add_zero_shadow(), and onlines as many sections as vmemmap pages fully span. - mhp_deinit_memmap_on_memory: Offlines as many sections as vmemmap pages fully span, removes the range from zhe zone by remove_pfn_range_from_zone(), and calls kasan_remove_zero_shadow() for the range. The new function memory_block_online() calls mhp_init_memmap_on_memory() before doing the actual online_pages(). Should online_pages() fail, we clean up by calling mhp_deinit_memmap_on_memory(). Adjusting of present_pages is done at the end once we know that online_pages() succedeed. On offline, memory_block_offline() needs to unaccount vmemmap pages from present_pages() before calling offline_pages(). This is necessary because offline_pages() tears down some structures based on the fact whether the node or the zone become empty. If offline_pages() fails, we account back vmemmap pages. If it succeeds, we call mhp_deinit_memmap_on_memory(). Hot-remove: We need to be careful when removing memory, as adding and removing memory needs to be done with the same granularity. To check that this assumption is not violated, we check the memory range we want to remove and if a) any memory block has vmemmap pages and b) the range spans more than a single memory block, we scream out loud and refuse to proceed. If all is good and the range was using memmap on memory (aka vmemmap pages), we construct an altmap structure so free_hugepage_table does the right thing and calls vmem_altmap_free instead of free_pagetable. Link: https://lkml.kernel.org/r/20210421102701.25051-5-osalvador@suse.de Signed-off-by: Oscar Salvador Reviewed-by: David Hildenbrand Acked-by: Michal Hocko Cc: Anshuman Khandual Cc: Pavel Tatashin Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm,memory_hotplug: factor out adjusting present pages into adjust_present_page_count()

2021-05-05T18:27:26+00:00

Let's have a single place (inspired by adjust_managed_page_count()) where we adjust present pages. In contrast to adjust_managed_page_count(), only memory onlining or offlining is allowed to modify the number of present pages. Link: https://lkml.kernel.org/r/20210421102701.25051-4-osalvador@suse.de Signed-off-by: David Hildenbrand Signed-off-by: Oscar Salvador Acked-by: Michal Hocko Cc: Anshuman Khandual Cc: Pavel Tatashin Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm,memory_hotplug: relax fully spanned sections check

2021-05-05T18:27:26+00:00

We want {online,offline}_pages to operate on whole memblocks, but memmap_on_memory will poke pageblock_nr_pages aligned holes in the beginning, which is a special case we want to allow. Relax the check to account for that case. Link: https://lkml.kernel.org/r/20210421102701.25051-3-osalvador@suse.de Signed-off-by: Oscar Salvador Reviewed-by: David Hildenbrand Acked-by: Michal Hocko Cc: Anshuman Khandual Cc: Pavel Tatashin Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: disable LRU pagevec during the migration temporarily

2021-05-05T18:27:24+00:00

LRU pagevec holds refcount of pages until the pagevec are drained. It could prevent migration since the refcount of the page is greater than the expection in migration logic. To mitigate the issue, callers of migrate_pages drains LRU pagevec via migrate_prep or lru_add_drain_all before migrate_pages call. However, it's not enough because pages coming into pagevec after the draining call still could stay at the pagevec so it could keep preventing page migration. Since some callers of migrate_pages have retrial logic with LRU draining, the page would migrate at next trail but it is still fragile in that it doesn't close the fundamental race between upcoming LRU pages into pagvec and migration so the migration failure could cause contiguous memory allocation failure in the end. To close the race, this patch disables lru caches(i.e, pagevec) during ongoing migration until migrate is done. Since it's really hard to reproduce, I measured how many times migrate_pages retried with force mode(it is about a fallback to a sync migration) with below debug code. int migrate_pages(struct list_head *from, new_page_t get_new_page, .. .. if (rc && reason == MR_CONTIG_RANGE && pass > 2) { printk(KERN_ERR, "pfn 0x%lx reason %d", page_to_pfn(page), rc); dump_page(page, "fail to migrate"); } The test was repeating android apps launching with cma allocation in background every five seconds. Total cma allocation count was about 500 during the testing. With this patch, the dump_page count was reduced from 400 to 30. The new interface is also useful for memory hotplug which currently drains lru pcp caches after each migration failure. This is rather suboptimal as it has to disrupt others running during the operation. With the new interface the operation happens only once. This is also in line with pcp allocator cache which are disabled for the offlining as well. Link: https://lkml.kernel.org/r/20210319175127.886124-1-minchan@kernel.org Signed-off-by: Minchan Kim Reviewed-by: Chris Goldsworthy Acked-by: Michal Hocko Cc: John Dias Cc: Suren Baghdasaryan Cc: Matthew Wilcox Cc: David Hildenbrand Cc: Vlastimil Babka Cc: Oliver Sang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

arm64: mte: Map hotplugged memory as Normal Tagged

2021-03-10T10:56:46+00:00

In a system supporting MTE, the linear map must allow reading/writing allocation tags by setting the memory type as Normal Tagged. Currently, this is only handled for memory present at boot. Hotplugged memory uses Normal non-Tagged memory. Introduce pgprot_mhp() for hotplugged memory and use it in add_memory_resource(). The arm64 code maps pgprot_mhp() to pgprot_tagged(). Note that ZONE_DEVICE memory should not be mapped as Tagged and therefore setting the memory type in arch_add_memory() is not feasible. Signed-off-by: Catalin Marinas Fixes: 0178dc761368 ("arm64: mte: Use Normal Tagged attributes for the linear map") Reported-by: Patrick Daly Tested-by: Patrick Daly Link: https://lore.kernel.org/r/1614745263-27827-1-git-send-email-pdaly@codeaurora.org Cc: # 5.10.x Cc: Will Deacon Cc: Andrew Morton Cc: Vincenzo Frascino Cc: David Hildenbrand Reviewed-by: David Hildenbrand Reviewed-by: Vincenzo Frascino Reviewed-by: Anshuman Khandual Link: https://lore.kernel.org/r/20210309122601.5543-1-catalin.marinas@arm.com Signed-off-by: Will Deacon

mm/memory_hotplug: prevalidate the address range being added with platform

2021-02-26T17:41:00+00:00

Patch series "mm/memory_hotplug: Pre-validate the address range with platform", v5. This series adds a mechanism allowing platforms to weigh in and prevalidate incoming address range before proceeding further with the memory hotplug. This helps prevent potential platform errors for the given address range, down the hotplug call chain, which inevitably fails the hotplug itself. This mechanism was suggested by David Hildenbrand during another discussion with respect to a memory hotplug fix on arm64 platform. https://lore.kernel.org/linux-arm-kernel/1600332402-30123-1-git-send-email-anshuman.khandual@arm.com/ This mechanism focuses on the addressibility aspect and not [sub] section alignment aspect. Hence check_hotplug_memory_range() and check_pfn_span() have been left unchanged. This patch (of 4): This introduces mhp_range_allowed() which can be called in various memory hotplug paths to prevalidate the address range which is being added, with the platform. Then mhp_range_allowed() calls mhp_get_pluggable_range() which provides applicable address range depending on whether linear mapping is required or not. For ranges that require linear mapping, it calls a new arch callback arch_get_mappable_range() which the platform can override. So the new callback, in turn provides the platform an opportunity to configure acceptable memory hotplug address ranges in case there are constraints. This mechanism will help prevent platform specific errors deep down during hotplug calls. This drops now redundant check_hotplug_memory_addressable() check in __add_pages() but instead adds a VM_BUG_ON() check which would ensure that the range has been validated with mhp_range_allowed() earlier in the call chain. Besides mhp_get_pluggable_range() also can be used by potential memory hotplug callers to avail the allowed physical range which would go through on a given platform. This does not really add any new range check in generic memory hotplug but instead compensates for lost checks in arch_add_memory() where applicable and check_hotplug_memory_addressable(), with unified mhp_range_allowed(). [akpm@linux-foundation.org: make pagemap_range() return -EINVAL when mhp_range_allowed() fails] Link: https://lkml.kernel.org/r/1612149902-7867-1-git-send-email-anshuman.khandual@arm.com Link: https://lkml.kernel.org/r/1612149902-7867-2-git-send-email-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual Suggested-by: David Hildenbrand Reviewed-by: David Hildenbrand Reviewed-by: Oscar Salvador Cc: Heiko Carstens Cc: Catalin Marinas Cc: Vasily Gorbik # s390 Cc: Will Deacon Cc: Ard Biesheuvel Cc: Mark Rutland Cc: Jason Wang Cc: Jonathan Cameron Cc: "Michael S. Tsirkin" Cc: Michal Hocko Cc: Pankaj Gupta Cc: Pankaj Gupta Cc: teawater Cc: Wei Yang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory_hotplug: use helper function zone_end_pfn() to get end_pfn

2021-02-26T17:41:00+00:00

Commit 108bcc96ef70 ("mm: add & use zone_end_pfn() and zone_spans_pfn()") introduced the helper zone_end_pfn() to calculate the zone end pfn. But update_pgdat_span() forgot to use it. Use this helper and rename local variable zone_end_pfn to end_pfn to avoid a naming conflict with the existing zone_end_pfn(). Link: https://lkml.kernel.org/r/20210127093211.37714-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Reviewed-by: David Hildenbrand Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory_hotplug: MEMHP_MERGE_RESOURCE -> MHP_MERGE_RESOURCE

2021-02-26T17:41:00+00:00

Let's make "MEMHP_MERGE_RESOURCE" consistent with "MHP_NONE", "mhp_t" and "mhp_flags". As discussed recently [1], "mhp" is our internal acronym for memory hotplug now. [1] https://lore.kernel.org/linux-mm/c37de2d0-28a1-4f7d-f944-cfd7d81c334d@redhat.com/ Link: https://lkml.kernel.org/r/20210126115829.10909-1-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Miaohe Lin Acked-by: Michael S. Tsirkin Reviewed-by: Oscar Salvador Acked-by: Wei Liu Reviewed-by: Pankaj Gupta Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: Stephen Hemminger Cc: Jason Wang Cc: Boris Ostrovsky Cc: Juergen Gross Cc: Stefano Stabellini Cc: Michal Hocko Cc: Anshuman Khandual Cc: Wei Yang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds