linux/mm/memory_hotplug.c, branch v5.10

mm: fix phys_to_target_node() and memory_add_physaddr_to_nid() exports

2020-11-22T18:48:22Z

The core-mm has a default __weak implementation of phys_to_target_node() to mirror the weak definition of memory_add_physaddr_to_nid(). That symbol is exported for modules. However, while the export in mm/memory_hotplug.c exported the symbol in the configuration cases of: CONFIG_NUMA_KEEP_MEMINFO=y CONFIG_MEMORY_HOTPLUG=y ...and: CONFIG_NUMA_KEEP_MEMINFO=n CONFIG_MEMORY_HOTPLUG=y ...it failed to export the symbol in the case of: CONFIG_NUMA_KEEP_MEMINFO=y CONFIG_MEMORY_HOTPLUG=n Not only is that broken, but Christoph points out that the kernel should not be exporting any __weak symbol, which means that memory_add_physaddr_to_nid() example that phys_to_target_node() copied is broken too. Rework the definition of phys_to_target_node() and memory_add_physaddr_to_nid() to not require weak symbols. Move to the common arch override design-pattern of an asm header defining a symbol to replace the default implementation. The only common header that all memory_add_physaddr_to_nid() producing architectures implement is asm/sparsemem.h. In fact, powerpc already defines its memory_add_physaddr_to_nid() helper in sparsemem.h. Double-down on that observation and define phys_to_target_node() where necessary in asm/sparsemem.h. An alternate consideration that was discarded was to put this override in asm/numa.h, but that entangles with the definition of MAX_NUMNODES relative to the inclusion of linux/nodemask.h, and requires powerpc to grow a new header. The dependency on NUMA_KEEP_MEMINFO for DEV_DAX_HMEM_DEVICES is invalid now that the symbol is properly exported / stubbed in all combinations of CONFIG_NUMA_KEEP_MEMINFO and CONFIG_MEMORY_HOTPLUG. [dan.j.williams@intel.com: v4] Link: https://lkml.kernel.org/r/160461461867.1505359.5301571728749534585.stgit@dwillia2-desk3.amr.corp.intel.com [dan.j.williams@intel.com: powerpc: fix create_section_mapping compile warning] Link: https://lkml.kernel.org/r/160558386174.2948926.2740149041249041764.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: a035b6bf863e ("mm/memory_hotplug: introduce default phys_to_target_node() implementation") Reported-by: Randy Dunlap Reported-by: Thomas Gleixner Reported-by: kernel test robot Reported-by: Christoph Hellwig Signed-off-by: Dan Williams Signed-off-by: Andrew Morton Tested-by: Randy Dunlap Tested-by: Thomas Gleixner Reviewed-by: Thomas Gleixner Reviewed-by: Christoph Hellwig Cc: Joao Martins Cc: Tony Luck Cc: Fenghua Yu Cc: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Vishal Verma Cc: Stephen Rothwell Link: https://lkml.kernel.org/r/160447639846.1133764.7044090803980177548.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Linus Torvalds

mm/memory_hotplug: remove a wrapper for alloc_migration_target()

2020-10-18T16:27:09Z

To calculate the correct node to migrate the page for hotplug, we need to check node id of the page. Wrapper for alloc_migration_target() exists for this purpose. However, Vlastimil informs that all migration source pages come from a single node. In this case, we don't need to check the node id for each page and we don't need to re-set the target nodemask for each page by using the wrapper. Set up the migration_target_control once and use it for all pages. Signed-off-by: Joonsoo Kim Signed-off-by: Andrew Morton Acked-by: Vlastimil Babka Acked-by: Michal Hocko Cc: Christoph Hellwig Cc: Mike Kravetz Cc: Naoya Horiguchi Cc: Roman Gushchin Link: http://lkml.kernel.org/r/1594622517-20681-10-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Linus Torvalds

mm/memory_hotplug: update comment regarding zone shuffling

2020-10-16T18:11:18Z

As we no longer shuffle via generic_online_page() and when undoing isolation, we can simplify the comment. We now effectively shuffle only once (properly) when onlining new memory. Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton Reviewed-by: Wei Yang Acked-by: Michal Hocko Cc: Alexander Duyck Cc: Mel Gorman Cc: Michal Hocko Cc: Dave Hansen Cc: Vlastimil Babka Cc: Wei Yang Cc: Oscar Salvador Cc: Mike Rapoport Cc: Pankaj Gupta Cc: Haiyang Zhang Cc: "K. Y. Srinivasan" Cc: Matthew Wilcox Cc: Michael Ellerman Cc: Scott Cheloha Cc: Stephen Hemminger Cc: Wei Liu Link: https://lkml.kernel.org/r/20201005121534.15649-6-david@redhat.com Signed-off-by: Linus Torvalds

mm: don't panic when links can't be created in sysfs

2020-10-16T18:11:18Z

At boot time, or when doing memory hot-add operations, if the links in sysfs can't be created, the system is still able to run, so just report the error in the kernel log rather than BUG_ON and potentially make system unusable because the callpath can be called with locks held. Since the number of memory blocks managed could be high, the messages are rate limited. As a consequence, link_mem_sections() has no status to report anymore. Signed-off-by: Laurent Dufour Signed-off-by: Andrew Morton Reviewed-by: Oscar Salvador Acked-by: Michal Hocko Acked-by: David Hildenbrand Cc: Greg Kroah-Hartman Cc: Fenghua Yu Cc: Nathan Lynch Cc: "Rafael J . Wysocki" Cc: Scott Cheloha Cc: Tony Luck Link: https://lkml.kernel.org/r/20200915094143.79181-4-ldufour@linux.ibm.com Signed-off-by: Linus Torvalds

kernel/resource: make iomem_resource implicit in release_mem_region_adjustable()

2020-10-16T18:11:18Z

"mem" in the name already indicates the root, similar to release_mem_region() and devm_request_mem_region(). Make it implicit. The only single caller always passes iomem_resource, other parents are not applicable. Suggested-by: Wei Yang Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton Reviewed-by: Wei Yang Cc: Michal Hocko Cc: Dan Williams Cc: Jason Gunthorpe Cc: Kees Cook Cc: Ard Biesheuvel Cc: Pankaj Gupta Cc: Baoquan He Link: https://lkml.kernel.org/r/20200916073041.10355-1-david@redhat.com Signed-off-by: Linus Torvalds

mm/memory_hotplug: MEMHP_MERGE_RESOURCE to specify merging of System RAM resources

2020-10-16T18:11:18Z

Some add_memory*() users add memory in small, contiguous memory blocks. Examples include virtio-mem, hyper-v balloon, and the XEN balloon. This can quickly result in a lot of memory resources, whereby the actual resource boundaries are not of interest (e.g., it might be relevant for DIMMs, exposed via /proc/iomem to user space). We really want to merge added resources in this scenario where possible. Let's provide a flag (MEMHP_MERGE_RESOURCE) to specify that a resource either created within add_memory*() or passed via add_memory_resource() shall be marked mergeable and merged with applicable siblings. To implement that, we need a kernel/resource interface to mark selected System RAM resources mergeable (IORESOURCE_SYSRAM_MERGEABLE) and trigger merging. Note: We really want to merge after the whole operation succeeded, not directly when adding a resource to the resource tree (it would break add_memory_resource() and require splitting resources again when the operation failed - e.g., due to -ENOMEM). Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton Reviewed-by: Pankaj Gupta Cc: Michal Hocko Cc: Dan Williams Cc: Jason Gunthorpe Cc: Kees Cook Cc: Ard Biesheuvel Cc: Thomas Gleixner Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: Stephen Hemminger Cc: Wei Liu Cc: Boris Ostrovsky Cc: Juergen Gross Cc: Stefano Stabellini Cc: Roger Pau Monné Cc: Julien Grall Cc: Baoquan He Cc: Wei Yang Cc: Anton Blanchard Cc: Benjamin Herrenschmidt Cc: Christian Borntraeger Cc: Dave Jiang Cc: Eric Biederman Cc: Greg Kroah-Hartman Cc: Heiko Carstens Cc: Jason Wang Cc: Len Brown Cc: Leonardo Bras Cc: Libor Pechacek Cc: Michael Ellerman Cc: "Michael S. Tsirkin" Cc: Nathan Lynch Cc: "Oliver O'Halloran" Cc: Paul Mackerras Cc: Pingfan Liu Cc: "Rafael J. Wysocki" Cc: Vasily Gorbik Cc: Vishal Verma Link: https://lkml.kernel.org/r/20200911103459.10306-6-david@redhat.com Signed-off-by: Linus Torvalds

mm/memory_hotplug: prepare passing flags to add_memory() and friends

2020-10-16T18:11:18Z

We soon want to pass flags, e.g., to mark added System RAM resources. mergeable. Prepare for that. This patch is based on a similar patch by Oscar Salvador: https://lkml.kernel.org/r/20190625075227.15193-3-osalvador@suse.de Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton Reviewed-by: Juergen Gross # Xen related part Reviewed-by: Pankaj Gupta Acked-by: Wei Liu Cc: Michal Hocko Cc: Dan Williams Cc: Jason Gunthorpe Cc: Baoquan He Cc: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: "Rafael J. Wysocki" Cc: Len Brown Cc: Greg Kroah-Hartman Cc: Vishal Verma Cc: Dave Jiang Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: Stephen Hemminger Cc: Wei Liu Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: David Hildenbrand Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Boris Ostrovsky Cc: Stefano Stabellini Cc: "Oliver O'Halloran" Cc: Pingfan Liu Cc: Nathan Lynch Cc: Libor Pechacek Cc: Anton Blanchard Cc: Leonardo Bras Cc: Ard Biesheuvel Cc: Eric Biederman Cc: Julien Grall Cc: Kees Cook Cc: Roger Pau Monné Cc: Thomas Gleixner Cc: Wei Yang Link: https://lkml.kernel.org/r/20200911103459.10306-5-david@redhat.com Signed-off-by: Linus Torvalds

kernel/resource: move and rename IORESOURCE_MEM_DRIVER_MANAGED

2020-10-16T18:11:18Z

IORESOURCE_MEM_DRIVER_MANAGED currently uses an unused PnP bit, which is always set to 0 by hardware. This is far from beautiful (and confusing), and the bit only applies to SYSRAM. So let's move it out of the bus-specific (PnP) defined bits. We'll add another SYSRAM specific bit soon. If we ever need more bits for other purposes, we can steal some from "desc", or reshuffle/regroup what we have. Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton Cc: Michal Hocko Cc: Dan Williams Cc: Jason Gunthorpe Cc: Kees Cook Cc: Ard Biesheuvel Cc: Pankaj Gupta Cc: Baoquan He Cc: Wei Yang Cc: Eric Biederman Cc: Thomas Gleixner Cc: Greg Kroah-Hartman Cc: Anton Blanchard Cc: Benjamin Herrenschmidt Cc: Boris Ostrovsky Cc: Christian Borntraeger Cc: Dave Jiang Cc: Haiyang Zhang Cc: Heiko Carstens Cc: Jason Wang Cc: Juergen Gross Cc: Julien Grall Cc: "K. Y. Srinivasan" Cc: Len Brown Cc: Leonardo Bras Cc: Libor Pechacek Cc: Michael Ellerman Cc: "Michael S. Tsirkin" Cc: Nathan Lynch Cc: "Oliver O'Halloran" Cc: Paul Mackerras Cc: Pingfan Liu Cc: "Rafael J. Wysocki" Cc: Roger Pau Monné Cc: Stefano Stabellini Cc: Stephen Hemminger Cc: Vasily Gorbik Cc: Vishal Verma Cc: Wei Liu Link: https://lkml.kernel.org/r/20200911103459.10306-3-david@redhat.com Signed-off-by: Linus Torvalds

kernel/resource: make release_mem_region_adjustable() never fail

2020-10-16T18:11:17Z

Patch series "selective merging of system ram resources", v4. Some add_memory*() users add memory in small, contiguous memory blocks. Examples include virtio-mem, hyper-v balloon, and the XEN balloon. This can quickly result in a lot of memory resources, whereby the actual resource boundaries are not of interest (e.g., it might be relevant for DIMMs, exposed via /proc/iomem to user space). We really want to merge added resources in this scenario where possible. Resources are effectively stored in a list-based tree. Having a lot of resources not only wastes memory, it also makes traversing that tree more expensive, and makes /proc/iomem explode in size (e.g., requiring kexec-tools to manually merge resources when creating a kdump header. The current kexec-tools resource count limit does not allow for more than ~100GB of memory with a memory block size of 128MB on x86-64). Let's allow to selectively merge system ram resources by specifying a new flag for add_memory*(). Patch #5 contains a /proc/iomem example. Only tested with virtio-mem. This patch (of 8): Let's make sure splitting a resource on memory hotunplug will never fail. This will become more relevant once we merge selected System RAM resources - then, we'll trigger that case more often on memory hotunplug. In general, this function is already unlikely to fail. When we remove memory, we free up quite a lot of metadata (memmap, page tables, memory block device, etc.). The only reason it could really fail would be when injecting allocation errors. All other error cases inside release_mem_region_adjustable() seem to be sanity checks if the function would be abused in different context - let's add WARN_ON_ONCE() in these cases so we can catch them. [natechancellor@gmail.com: fix use of ternary condition in release_mem_region_adjustable] Link: https://lkml.kernel.org/r/20200922060748.2452056-1-natechancellor@gmail.com Link: https://github.com/ClangBuiltLinux/linux/issues/1159 Signed-off-by: David Hildenbrand Signed-off-by: Nathan Chancellor Signed-off-by: Andrew Morton Cc: Michal Hocko Cc: Dan Williams Cc: Jason Gunthorpe Cc: Kees Cook Cc: Ard Biesheuvel Cc: Pankaj Gupta Cc: Baoquan He Cc: Wei Yang Cc: Anton Blanchard Cc: Benjamin Herrenschmidt Cc: Boris Ostrovsky Cc: Christian Borntraeger Cc: Dave Jiang Cc: Eric Biederman Cc: Greg Kroah-Hartman Cc: Haiyang Zhang Cc: Heiko Carstens Cc: Jason Wang Cc: Juergen Gross Cc: Julien Grall Cc: "K. Y. Srinivasan" Cc: Len Brown Cc: Leonardo Bras Cc: Libor Pechacek Cc: Michael Ellerman Cc: "Michael S. Tsirkin" Cc: Nathan Lynch Cc: "Oliver O'Halloran" Cc: Paul Mackerras Cc: Pingfan Liu Cc: "Rafael J. Wysocki" Cc: Roger Pau Monn Cc: Stefano Stabellini Cc: Stephen Hemminger Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Vishal Verma Cc: Wei Liu Link: https://lkml.kernel.org/r/20200911103459.10306-2-david@redhat.com Signed-off-by: Linus Torvalds

mm/memory_hotplug: mark pageblocks MIGRATE_ISOLATE while onlining memory

2020-10-16T18:11:17Z

Currently, it can happen that pages are allocated (and freed) via the buddy before we finished basic memory onlining. For example, pages are exposed to the buddy and can be allocated before we actually mark the sections online. Allocated pages could suddenly fail pfn_to_online_page() checks. We had similar issues with pcp handling, when pages are allocated+freed before we reach zone_pcp_update() in online_pages() [1]. Instead, mark all pageblocks MIGRATE_ISOLATE, such that allocations are impossible. Once done with the heavy lifting, use undo_isolate_page_range() to move the pages to the MIGRATE_MOVABLE freelist, marking them ready for allocation. Similar to offline_pages(), we have to manually adjust zone->nr_isolate_pageblock. [1] https://lkml.kernel.org/r/1597150703-19003-1-git-send-email-charante@codeaurora.org Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton Reviewed-by: Oscar Salvador Acked-by: Michal Hocko Cc: Wei Yang Cc: Baoquan He Cc: Pankaj Gupta Cc: Charan Teja Reddy Cc: Dan Williams Cc: Fenghua Yu Cc: Logan Gunthorpe Cc: "Matthew Wilcox (Oracle)" Cc: Mel Gorman Cc: Mel Gorman Cc: Michel Lespinasse Cc: Mike Rapoport Cc: Tony Luck Link: https://lkml.kernel.org/r/20200819175957.28465-11-david@redhat.com Signed-off-by: Linus Torvalds