pm24.git/include/linux/memory_hotplug.h, branch v5.4-rc4

mm/sparsemem: support sub-section hotplug

2019-07-19T00:08:07Z

The libnvdimm sub-system has suffered a series of hacks and broken workarounds for the memory-hotplug implementation's awkward section-aligned (128MB) granularity. For example the following backtrace is emitted when attempting arch_add_memory() with physical address ranges that intersect 'System RAM' (RAM) with 'Persistent Memory' (PMEM) within a given section: # cat /proc/iomem | grep -A1 -B1 Persistent\ Memory 100000000-1ffffffff : System RAM 200000000-303ffffff : Persistent Memory (legacy) 304000000-43fffffff : System RAM 440000000-23ffffffff : Persistent Memory 2400000000-43bfffffff : Persistent Memory 2400000000-43bfffffff : namespace2.0 WARNING: CPU: 38 PID: 928 at arch/x86/mm/init_64.c:850 add_pages+0x5c/0x60 [..] RIP: 0010:add_pages+0x5c/0x60 [..] Call Trace: devm_memremap_pages+0x460/0x6e0 pmem_attach_disk+0x29e/0x680 [nd_pmem] ? nd_dax_probe+0xfc/0x120 [libnvdimm] nvdimm_bus_probe+0x66/0x160 [libnvdimm] It was discovered that the problem goes beyond RAM vs PMEM collisions as some platform produce PMEM vs PMEM collisions within a given section. The libnvdimm workaround for that case revealed that the libnvdimm section-alignment-padding implementation has been broken for a long while. A fix for that long-standing breakage introduces as many problems as it solves as it would require a backward-incompatible change to the namespace metadata interpretation. Instead of that dubious route [1], address the root problem in the memory-hotplug implementation. Note that EEXIST is no longer treated as success as that is how sparse_add_section() reports subsection collisions, it was also obviated by recent changes to perform the request_region() for 'System RAM' before arch_add_memory() in the add_memory() sequence. [1] https://lore.kernel.org/r/155000671719.348031.2347363160141119237.stgit@dwillia2-desk3.amr.corp.intel.com [osalvador@suse.de: fix deactivate_section for early sections] Link: http://lkml.kernel.org/r/20190715081549.32577-2-osalvador@suse.de Link: http://lkml.kernel.org/r/156092354368.979959.6232443923440952359.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Signed-off-by: Oscar Salvador Tested-by: Aneesh Kumar K.V [ppc64] Reviewed-by: Oscar Salvador Cc: Michal Hocko Cc: Vlastimil Babka Cc: Logan Gunthorpe Cc: Pavel Tatashin Cc: David Hildenbrand Cc: Jane Chu Cc: Jeff Moyer Cc: Jérôme Glisse Cc: Jonathan Corbet Cc: Mike Rapoport Cc: Toshi Kani Cc: Wei Yang Cc: Jason Gunthorpe Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/sparsemem: prepare for sub-section ranges

2019-07-19T00:08:07Z

Prepare the memory hot-{add,remove} paths for handling sub-section ranges by plumbing the starting page frame and number of pages being handled through arch_{add,remove}_memory() to sparse_{add,remove}_one_section(). This is simply plumbing, small cleanups, and some identifier renames. No intended functional changes. Link: http://lkml.kernel.org/r/156092353780.979959.9713046515562743194.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Reviewed-by: Pavel Tatashin Tested-by: Aneesh Kumar K.V [ppc64] Reviewed-by: Oscar Salvador Cc: Michal Hocko Cc: Vlastimil Babka Cc: Logan Gunthorpe Cc: David Hildenbrand Cc: Jane Chu Cc: Jeff Moyer Cc: Jérôme Glisse Cc: Jonathan Corbet Cc: Mike Rapoport Cc: Toshi Kani Cc: Wei Yang Cc: Jason Gunthorpe Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory_hotplug: move and simplify walk_memory_blocks()

2019-07-19T00:08:06Z

Let's move walk_memory_blocks() to the place where memory block logic resides and simplify it. While at it, add a type for the callback function. Link: http://lkml.kernel.org/r/20190614100114.311-6-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Andrew Morton Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: David Hildenbrand Cc: Stephen Rothwell Cc: Pavel Tatashin Cc: Andrew Banman Cc: Mike Travis Cc: Oscar Salvador Cc: Michal Hocko Cc: Wei Yang Cc: Arun KS Cc: Qian Cai Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory_hotplug: rename walk_memory_range() and pass start+size instead of pfns

2019-07-19T00:08:06Z

walk_memory_range() was once used to iterate over sections. Now, it iterates over memory blocks. Rename the function, fixup the documentation. Also, pass start+size instead of PFNs, which is what most callers already have at hand. (we'll rework link_mem_sections() most probably soon) Follow-up patches will rework, simplify, and move walk_memory_blocks() to drivers/base/memory.c. Note: walk_memory_blocks() only works correctly right now if the start_pfn is aligned to a section start. This is the case right now, but we'll generalize the function in a follow up patch so the semantics match the documentation. [akpm@linux-foundation.org: remove unused variable] Link: http://lkml.kernel.org/r/20190614100114.311-5-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Andrew Morton Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: "Rafael J. Wysocki" Cc: Len Brown Cc: Greg Kroah-Hartman Cc: David Hildenbrand Cc: Rashmica Gupta Cc: Pavel Tatashin Cc: Anshuman Khandual Cc: Michael Neuling Cc: Thomas Gleixner Cc: Oscar Salvador Cc: Michal Hocko Cc: Wei Yang Cc: Juergen Gross Cc: Qian Cai Cc: Arun KS Cc: Nick Desaulniers Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory_hotplug: remove "zone" parameter from sparse_remove_one_section

2019-07-19T00:08:06Z

The parameter is unused, so let's drop it. Memory removal paths should never care about zones. This is the job of memory offlining and will require more refactorings. Link: http://lkml.kernel.org/r/20190527111152.16324-12-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Dan Williams Reviewed-by: Wei Yang Reviewed-by: Oscar Salvador Acked-by: Michal Hocko Cc: Alex Deucher Cc: Andrew Banman Cc: Andy Lutomirski Cc: Anshuman Khandual Cc: Ard Biesheuvel Cc: Arun KS Cc: Baoquan He Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Chintan Pandya Cc: Christophe Leroy Cc: Chris Wilson Cc: Dave Hansen Cc: "David S. Miller" Cc: Fenghua Yu Cc: Greg Kroah-Hartman Cc: Heiko Carstens Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jonathan Cameron Cc: Joonsoo Kim Cc: Jun Yao Cc: "Kirill A. Shutemov" Cc: Logan Gunthorpe Cc: Mark Brown Cc: Mark Rutland Cc: Masahiro Yamada Cc: Mathieu Malaterre Cc: Michael Ellerman Cc: Mike Rapoport Cc: "mike.travis@hpe.com" Cc: Nicholas Piggin Cc: Paul Mackerras Cc: Pavel Tatashin Cc: Peter Zijlstra Cc: Qian Cai Cc: "Rafael J. Wysocki" Cc: Rich Felker Cc: Rob Herring Cc: Robin Murphy Cc: Thomas Gleixner Cc: Tony Luck Cc: Vasily Gorbik Cc: Will Deacon Cc: Yoshinori Sato Cc: Yu Zhao Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory_hotplug: drop MHP_MEMBLOCK_API

2019-07-19T00:08:06Z

No longer needed, the callers of arch_add_memory() can handle this manually. Link: http://lkml.kernel.org/r/20190527111152.16324-9-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Wei Yang Acked-by: Michal Hocko Cc: David Hildenbrand Cc: Oscar Salvador Cc: Pavel Tatashin Cc: Joonsoo Kim Cc: Qian Cai Cc: Arun KS Cc: Mathieu Malaterre Cc: Mike Rapoport Cc: Alex Deucher Cc: Andrew Banman Cc: Andy Lutomirski Cc: Anshuman Khandual Cc: Ard Biesheuvel Cc: Baoquan He Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Chintan Pandya Cc: Christophe Leroy Cc: Chris Wilson Cc: Dan Williams Cc: Dave Hansen Cc: "David S. Miller" Cc: Fenghua Yu Cc: Greg Kroah-Hartman Cc: Heiko Carstens Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jonathan Cameron Cc: Jun Yao Cc: "Kirill A. Shutemov" Cc: Logan Gunthorpe Cc: Mark Brown Cc: Mark Rutland Cc: Masahiro Yamada Cc: Michael Ellerman Cc: Mike Rapoport Cc: "mike.travis@hpe.com" Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Paul Mackerras Cc: Peter Zijlstra Cc: "Rafael J. Wysocki" Cc: Rich Felker Cc: Rob Herring Cc: Robin Murphy Cc: Thomas Gleixner Cc: Tony Luck Cc: Vasily Gorbik Cc: Will Deacon Cc: Yoshinori Sato Cc: Yu Zhao Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory_hotplug: allow arch_remove_memory() without CONFIG_MEMORY_HOTREMOVE

2019-07-19T00:08:06Z

We want to improve error handling while adding memory by allowing to use arch_remove_memory() and __remove_pages() even if CONFIG_MEMORY_HOTREMOVE is not set to e.g., implement something like: arch_add_memory() rc = do_something(); if (rc) { arch_remove_memory(); } We won't get rid of CONFIG_MEMORY_HOTREMOVE for now, as it will require quite some dependencies for memory offlining. Link: http://lkml.kernel.org/r/20190527111152.16324-7-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Pavel Tatashin Cc: Tony Luck Cc: Fenghua Yu Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Heiko Carstens Cc: Yoshinori Sato Cc: Rich Felker Cc: Dave Hansen Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: Michal Hocko Cc: David Hildenbrand Cc: Oscar Salvador Cc: "Kirill A. Shutemov" Cc: Alex Deucher Cc: "David S. Miller" Cc: Mark Brown Cc: Chris Wilson Cc: Christophe Leroy Cc: Nicholas Piggin Cc: Vasily Gorbik Cc: Rob Herring Cc: Masahiro Yamada Cc: "mike.travis@hpe.com" Cc: Andrew Banman Cc: Arun KS Cc: Qian Cai Cc: Mathieu Malaterre Cc: Baoquan He Cc: Logan Gunthorpe Cc: Anshuman Khandual Cc: Ard Biesheuvel Cc: Catalin Marinas Cc: Chintan Pandya Cc: Dan Williams Cc: Ingo Molnar Cc: Jonathan Cameron Cc: Joonsoo Kim Cc: Jun Yao Cc: Mark Rutland Cc: Mike Rapoport Cc: Oscar Salvador Cc: Robin Murphy Cc: Wei Yang Cc: Will Deacon Cc: Yu Zhao Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/hotplug: make remove_memory() interface usable

2019-07-17T02:23:24Z

Presently the remove_memory() interface is inherently broken. It tries to remove memory but panics if some memory is not offline. The problem is that it is impossible to ensure that all memory blocks are offline as this function also takes lock_device_hotplug that is required to change memory state via sysfs. So, between calling this function and offlining all memory blocks there is always a window when lock_device_hotplug is released, and therefore, there is always a chance for a panic during this window. Make this interface to return an error if memory removal fails. This way it is safe to call this function without panicking machine, and also makes it symmetric to add_memory() which already returns an error. Link: http://lkml.kernel.org/r/20190517215438.6487-3-pasha.tatashin@soleen.com Signed-off-by: Pavel Tatashin Reviewed-by: David Hildenbrand Acked-by: Michal Hocko Cc: Bjorn Helgaas Cc: Borislav Petkov Cc: Dan Williams Cc: Dave Hansen Cc: Dave Hansen Cc: Dave Jiang Cc: Fengguang Wu Cc: Huang Ying Cc: James Morris Cc: Jérôme Glisse Cc: Keith Busch Cc: Ross Zwisler Cc: Sasha Levin Cc: Takashi Iwai Cc: Tom Lendacky Cc: Vishal Verma Cc: Yaowei Bai Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory_hotplug: make __remove_pages() and arch_remove_memory() never fail

2019-05-14T16:47:50Z

All callers of arch_remove_memory() ignore errors. And we should really try to remove any errors from the memory removal path. No more errors are reported from __remove_pages(). BUG() in s390x code in case arch_remove_memory() is triggered. We may implement that properly later. WARN in case powerpc code failed to remove the section mapping, which is better than ignoring the error completely right now. Link: http://lkml.kernel.org/r/20190409100148.24703-5-david@redhat.com Signed-off-by: David Hildenbrand Cc: Tony Luck Cc: Fenghua Yu Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Yoshinori Sato Cc: Rich Felker Cc: Dave Hansen Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Michal Hocko Cc: Mike Rapoport Cc: Oscar Salvador Cc: "Kirill A. Shutemov" Cc: Christophe Leroy Cc: Stefan Agner Cc: Nicholas Piggin Cc: Pavel Tatashin Cc: Vasily Gorbik Cc: Arun KS Cc: Geert Uytterhoeven Cc: Masahiro Yamada Cc: Rob Herring Cc: Joonsoo Kim Cc: Wei Yang Cc: Qian Cai Cc: Mathieu Malaterre Cc: Andrew Banman Cc: Greg Kroah-Hartman Cc: Ingo Molnar Cc: Mike Travis Cc: Oscar Salvador Cc: "Rafael J. Wysocki" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, memory_hotplug: provide a more generic restrictions for memory hotplug

2019-05-14T16:47:49Z

arch_add_memory, __add_pages take a want_memblock which controls whether the newly added memory should get the sysfs memblock user API (e.g. ZONE_DEVICE users do not want/need this interface). Some callers even want to control where do we allocate the memmap from by configuring altmap. Add a more generic hotplug context for arch_add_memory and __add_pages. struct mhp_restrictions contains flags which contains additional features to be enabled by the memory hotplug (MHP_MEMBLOCK_API currently) and altmap for alternative memmap allocator. This patch shouldn't introduce any functional change. [akpm@linux-foundation.org: build fix] Link: http://lkml.kernel.org/r/20190408082633.2864-3-osalvador@suse.de Signed-off-by: Michal Hocko Signed-off-by: Oscar Salvador Cc: Dan Williams Cc: David Hildenbrand Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds