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2020-01-04mm/memory_hotplug: shrink zones when offlining memoryDavid Hildenbrand
We currently try to shrink a single zone when removing memory. We use the zone of the first page of the memory we are removing. If that memmap was never initialized (e.g., memory was never onlined), we will read garbage and can trigger kernel BUGs (due to a stale pointer): BUG: unable to handle page fault for address: 000000000000353d #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP PTI CPU: 1 PID: 7 Comm: kworker/u8:0 Not tainted 5.3.0-rc5-next-20190820+ #317 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.4 Workqueue: kacpi_hotplug acpi_hotplug_work_fn RIP: 0010:clear_zone_contiguous+0x5/0x10 Code: 48 89 c6 48 89 c3 e8 2a fe ff ff 48 85 c0 75 cf 5b 5d c3 c6 85 fd 05 00 00 01 5b 5d c3 0f 1f 840 RSP: 0018:ffffad2400043c98 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000200000000 RCX: 0000000000000000 RDX: 0000000000200000 RSI: 0000000000140000 RDI: 0000000000002f40 RBP: 0000000140000000 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000140000 R13: 0000000000140000 R14: 0000000000002f40 R15: ffff9e3e7aff3680 FS: 0000000000000000(0000) GS:ffff9e3e7bb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000353d CR3: 0000000058610000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __remove_pages+0x4b/0x640 arch_remove_memory+0x63/0x8d try_remove_memory+0xdb/0x130 __remove_memory+0xa/0x11 acpi_memory_device_remove+0x70/0x100 acpi_bus_trim+0x55/0x90 acpi_device_hotplug+0x227/0x3a0 acpi_hotplug_work_fn+0x1a/0x30 process_one_work+0x221/0x550 worker_thread+0x50/0x3b0 kthread+0x105/0x140 ret_from_fork+0x3a/0x50 Modules linked in: CR2: 000000000000353d Instead, shrink the zones when offlining memory or when onlining failed. Introduce and use remove_pfn_range_from_zone(() for that. We now properly shrink the zones, even if we have DIMMs whereby - Some memory blocks fall into no zone (never onlined) - Some memory blocks fall into multiple zones (offlined+re-onlined) - Multiple memory blocks that fall into different zones Drop the zone parameter (with a potential dubious value) from __remove_pages() and __remove_section(). Link: http://lkml.kernel.org/r/20191006085646.5768-6-david@redhat.com Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after d0dc12e86b319] Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: <stable@vger.kernel.org> [5.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01mm/memory_hotplug.c: remove __online_page_set_limits()Souptick Joarder
__online_page_set_limits() is a dummy function - remove it and all callers. Link: http://lkml.kernel.org/r/8e1bc9d3b492f6bde16e95ebc1dee11d6aefabd7.1567889743.git.jrdr.linux@gmail.com Link: http://lkml.kernel.org/r/854db2cf8145d9635249c95584d9a91fd774a229.1567889743.git.jrdr.linux@gmail.com Link: http://lkml.kernel.org/r/9afe6c5a18158f3884a6b302ac2c772f3da49ccc.1567889743.git.jrdr.linux@gmail.com Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01mm/memory_hotplug.c: don't allow to online/offline memory blocks with holesDavid Hildenbrand
Our onlining/offlining code is unnecessarily complicated. Only memory blocks added during boot can have holes (a range that is not IORESOURCE_SYSTEM_RAM). Hotplugged memory never has holes (e.g., see add_memory_resource()). All memory blocks that belong to boot memory are already online. Note that boot memory can have holes and the memmap of the holes is marked PG_reserved. However, also memory allocated early during boot is PG_reserved - basically every page of boot memory that is not given to the buddy is PG_reserved. Therefore, when we stop allowing to offline memory blocks with holes, we implicitly no longer have to deal with onlining memory blocks with holes. E.g., online_pages() will do a walk_system_ram_range(..., online_pages_range), whereby online_pages_range() will effectively only free the memory holes not falling into a hole to the buddy. The other pages (holes) are kept PG_reserved (via move_pfn_range_to_zone()->memmap_init_zone()). This allows to simplify the code. For example, we no longer have to worry about marking pages that fall into memory holes PG_reserved when onlining memory. We can stop setting pages PG_reserved completely in memmap_init_zone(). Offlining memory blocks added during boot is usually not guaranteed to work either way (unmovable data might have easily ended up on that memory during boot). So stopping to do that should not really hurt. Also, people are not even aware of a setup where onlining/offlining of memory blocks with holes used to work reliably (see [1] and [2] especially regarding the hotplug path) - I doubt it worked reliably. For the use case of offlining memory to unplug DIMMs, we should see no change. (holes on DIMMs would be weird). Please note that hardware errors (PG_hwpoison) are not memory holes and are not affected by this change when offlining. [1] https://lkml.org/lkml/2019/10/22/135 [2] https://lkml.org/lkml/2019/8/14/1365 Link: http://lkml.kernel.org/r/20191119115237.6662-1-david@redhat.com Reviewed-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01mm/page_isolation.c: convert SKIP_HWPOISON to MEMORY_OFFLINEDavid Hildenbrand
We have two types of users of page isolation: 1. Memory offlining: Offline memory so it can be unplugged. Memory won't be touched. 2. Memory allocation: Allocate memory (e.g., alloc_contig_range()) to become the owner of the memory and make use of it. For example, in case we want to offline memory, we can ignore (skip over) PageHWPoison() pages, as the memory won't get used. We can allow to offline memory. In contrast, we don't want to allow to allocate such memory. Let's generalize the approach so we can special case other types of pages we want to skip over in case we offline memory. While at it, also pass the same flags to test_pages_isolated(). Link: http://lkml.kernel.org/r/20191021172353.3056-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Suggested-by: Michal Hocko <mhocko@suse.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Pingfan Liu <kernelfans@gmail.com> Cc: Qian Cai <cai@lca.pw> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Pavel Tatashin <pavel.tatashin@microsoft.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01mm/page_alloc.c: don't set pages PageReserved() when offliningDavid Hildenbrand
Patch series "mm: Memory offlining + page isolation cleanups", v2. This patch (of 2): We call __offline_isolated_pages() from __offline_pages() after all pages were isolated and are either free (PageBuddy()) or PageHWPoison. Nothing can stop us from offlining memory at this point. In __offline_isolated_pages() we first set all affected memory sections offline (offline_mem_sections(pfn, end_pfn)), to mark the memmap as invalid (pfn_to_online_page() will no longer succeed), and then walk over all pages to pull the free pages from the free lists (to the isolated free lists, to be precise). Note that re-onlining a memory block will result in the whole memmap getting reinitialized, overwriting any old state. We already poision the memmap when offlining is complete to find any access to stale/uninitialized memmaps. So, setting the pages PageReserved() is not helpful. The memap is marked offline and all pageblocks are isolated. As soon as offline, the memmap is stale either way. This looks like a leftover from ancient times where we initialized the memmap when adding memory and not when onlining it (the pages were set PageReserved so re-onling would work as expected). Link: http://lkml.kernel.org/r/20191021172353.3056-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Oscar Salvador <osalvador@suse.de> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Pavel Tatashin <pavel.tatashin@microsoft.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Pingfan Liu <kernelfans@gmail.com> Cc: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01mm/memory_hotplug: remove __online_page_free() and ↵David Hildenbrand
__online_page_increment_counters() Let's drop the now unused functions. Link: http://lkml.kernel.org/r/20190909114830.662-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Qian Cai <cai@lca.pw> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Sasha Levin <sashal@kernel.org> Cc: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01mm/memory_hotplug: export generic_online_page()David Hildenbrand
Patch series "mm/memory_hotplug: Export generic_online_page()". Let's replace the __online_page...() functions by generic_online_page(). Hyper-V only wants to delay the actual onlining of un-backed pages, so we can simpy re-use the generic function. This patch (of 3): Let's expose generic_online_page() so online_page_callback users can simply fall back to the generic implementation when actually deciding to online the pages. Link: http://lkml.kernel.org/r/20190909114830.662-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Qian Cai <cai@lca.pw> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Sasha Levin <sashal@kernel.org> Cc: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01mm/memory_hotplug.c: add a bounds check to __add_pages()Alastair D'Silva
On PowerPC, the address ranges allocated to OpenCAPI LPC memory are allocated from firmware. These address ranges may be higher than what older kernels permit, as we increased the maximum permissable address in commit 4ffe713b7587 ("powerpc/mm: Increase the max addressable memory to 2PB"). It is possible that the addressable range may change again in the future. In this scenario, we end up with a bogus section returned from __section_nr (see the discussion on the thread "mm: Trigger bug on if a section is not found in __section_nr"). Adding a check here means that we fail early and have an opportunity to handle the error gracefully, rather than rumbling on and potentially accessing an incorrect section. Further discussion is also on the thread ("powerpc: Perform a bounds check in arch_add_memory") http://lkml.kernel.org/r/20190827052047.31547-1-alastair@au1.ibm.com Link: http://lkml.kernel.org/r/20191001004617.7536-2-alastair@au1.ibm.com Signed-off-by: Alastair D'Silva <alastair@d-silva.org> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01mm/hotplug: reorder memblock_[free|remove]() calls in try_remove_memory()Anshuman Khandual
Currently during memory hot add procedure, memory gets into memblock before calling arch_add_memory() which creates its linear mapping. add_memory_resource() { .................. memblock_add_node() .................. arch_add_memory() .................. } But during memory hot remove procedure, removal from memblock happens first before its linear mapping gets teared down with arch_remove_memory() which is not consistent. Resource removal should happen in reverse order as they were added. However this does not pose any problem for now, unless there is an assumption regarding linear mapping. One example was a subtle failure on arm64 platform [1]. Though this has now found a different solution. try_remove_memory() { .................. memblock_free() memblock_remove() .................. arch_remove_memory() .................. } This changes the sequence of resource removal including memblock and linear mapping tear down during memory hot remove which will now be the reverse order in which they were added during memory hot add. The changed removal order looks like the following. try_remove_memory() { .................. arch_remove_memory() .................. memblock_free() memblock_remove() .................. } [1] https://patchwork.kernel.org/patch/11127623/ Memory hot remove now works on arm64 without this because a recent commit 60bb462fc7ad ("drivers/base/node.c: simplify unregister_memory_block_under_nodes()"). This does not fix a serious problem. It just removes an inconsistency while freeing resources during memory hot remove which for now does not pose a real problem. David mentioned that re-ordering should still make sense for consistency purpose (removing stuff in the reverse order they were added). This patch is now detached from arm64 hot-remove series. Michal: : I would just a note that the inconsistency doesn't pose any problem now : but if somebody makes any assumptions about linear mappings then it could : get subtly broken like your example for arm64 which has found a different : solution in the meantime. Link: http://lkml.kernel.org/r/1569380273-7708-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-22mm/memory_hotplug: don't access uninitialized memmaps in shrink_zone_span()David Hildenbrand
Let's limit shrinking to !ZONE_DEVICE so we can fix the current code. We should never try to touch the memmap of offline sections where we could have uninitialized memmaps and could trigger BUGs when calling page_to_nid() on poisoned pages. There is no reliable way to distinguish an uninitialized memmap from an initialized memmap that belongs to ZONE_DEVICE, as we don't have anything like SECTION_IS_ONLINE we can use similar to pfn_to_online_section() for !ZONE_DEVICE memory. E.g., set_zone_contiguous() similarly relies on pfn_to_online_section() and will therefore never set a ZONE_DEVICE zone consecutive. Stopping to shrink the ZONE_DEVICE therefore results in no observable changes, besides /proc/zoneinfo indicating different boundaries - something we can totally live with. Before commit d0dc12e86b31 ("mm/memory_hotplug: optimize memory hotplug"), the memmap was initialized with 0 and the node with the right value. So the zone might be wrong but not garbage. After that commit, both the zone and the node will be garbage when touching uninitialized memmaps. Toshiki reported a BUG (race between delayed initialization of ZONE_DEVICE memmaps without holding the memory hotplug lock and concurrent zone shrinking). https://lkml.org/lkml/2019/11/14/1040 "Iteration of create and destroy namespace causes the panic as below: kernel BUG at mm/page_alloc.c:535! CPU: 7 PID: 2766 Comm: ndctl Not tainted 5.4.0-rc4 #6 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.0-0-g63451fca13-prebuilt.qemu-project.org 04/01/2014 RIP: 0010:set_pfnblock_flags_mask+0x95/0xf0 Call Trace: memmap_init_zone_device+0x165/0x17c memremap_pages+0x4c1/0x540 devm_memremap_pages+0x1d/0x60 pmem_attach_disk+0x16b/0x600 [nd_pmem] nvdimm_bus_probe+0x69/0x1c0 really_probe+0x1c2/0x3e0 driver_probe_device+0xb4/0x100 device_driver_attach+0x4f/0x60 bind_store+0xc9/0x110 kernfs_fop_write+0x116/0x190 vfs_write+0xa5/0x1a0 ksys_write+0x59/0xd0 do_syscall_64+0x5b/0x180 entry_SYSCALL_64_after_hwframe+0x44/0xa9 While creating a namespace and initializing memmap, if you destroy the namespace and shrink the zone, it will initialize the memmap outside the zone and trigger VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page) in set_pfnblock_flags_mask()." This BUG is also mitigated by this commit, where we for now stop to shrink the ZONE_DEVICE zone until we can do it in a safe and clean way. Link: http://lkml.kernel.org/r/20191006085646.5768-5-david@redhat.com Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after d0dc12e86b319] Signed-off-by: David Hildenbrand <david@redhat.com> Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Reported-by: Toshiki Fukasawa <t-fukasawa@vx.jp.nec.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Damian Tometzki <damian.tometzki@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Halil Pasic <pasic@linux.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jun Yao <yaojun8558363@gmail.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Pankaj Gupta <pagupta@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Pavel Tatashin <pavel.tatashin@microsoft.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qian Cai <cai@lca.pw> Cc: Rich Felker <dalias@libc.org> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Steve Capper <steve.capper@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Yu Zhao <yuzhao@google.com> Cc: <stable@vger.kernel.org> [4.13+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-15mm/memory_hotplug: fix try_offline_node()David Hildenbrand
try_offline_node() is pretty much broken right now: - The node span is updated when onlining memory, not when adding it. We ignore memory that was mever onlined. Bad. - We touch possible garbage memmaps. The pfn_to_nid(pfn) can easily trigger a kernel panic. Bad for memory that is offline but also bad for subsection hotadd with ZONE_DEVICE, whereby the memmap of the first PFN of a section might contain garbage. - Sections belonging to mixed nodes are not properly considered. As memory blocks might belong to multiple nodes, we would have to walk all pageblocks (or at least subsections) within present sections. However, we don't have a way to identify whether a memmap that is not online was initialized (relevant for ZONE_DEVICE). This makes things more complicated. Luckily, we can piggy pack on the node span and the nid stored in memory blocks. Currently, the node span is grown when calling move_pfn_range_to_zone() - e.g., when onlining memory, and shrunk when removing memory, before calling try_offline_node(). Sysfs links are created via link_mem_sections(), e.g., during boot or when adding memory. If the node still spans memory or if any memory block belongs to the nid, we don't set the node offline. As memory blocks that span multiple nodes cannot get offlined, the nid stored in memory blocks is reliable enough (for such online memory blocks, the node still spans the memory). Introduce for_each_memory_block() to efficiently walk all memory blocks. Note: We will soon stop shrinking the ZONE_DEVICE zone and the node span when removing ZONE_DEVICE memory to fix similar issues (access of garbage memmaps) - until we have a reliable way to identify whether these memmaps were properly initialized. This implies later, that once a node had ZONE_DEVICE memory, we won't be able to set a node offline - which should be acceptable. Since commit f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") memory that is added is not assoziated with a zone/node (memmap not initialized). The introducing commit 60a5a19e7419 ("memory-hotplug: remove sysfs file of node") already missed that we could have multiple nodes for a section and that the zone/node span is updated when onlining pages, not when adding them. I tested this by hotplugging two DIMMs to a memory-less and cpu-less NUMA node. The node is properly onlined when adding the DIMMs. When removing the DIMMs, the node is properly offlined. Masayoshi Mizuma reported: : Without this patch, memory hotplug fails as panic: : : BUG: kernel NULL pointer dereference, address: 0000000000000000 : ... : Call Trace: : remove_memory_block_devices+0x81/0xc0 : try_remove_memory+0xb4/0x130 : __remove_memory+0xa/0x20 : acpi_memory_device_remove+0x84/0x100 : acpi_bus_trim+0x57/0x90 : acpi_bus_trim+0x2e/0x90 : acpi_device_hotplug+0x2b2/0x4d0 : acpi_hotplug_work_fn+0x1a/0x30 : process_one_work+0x171/0x380 : worker_thread+0x49/0x3f0 : kthread+0xf8/0x130 : ret_from_fork+0x35/0x40 [david@redhat.com: v3] Link: http://lkml.kernel.org/r/20191102120221.7553-1-david@redhat.com Link: http://lkml.kernel.org/r/20191028105458.28320-1-david@redhat.com Fixes: 60a5a19e7419 ("memory-hotplug: remove sysfs file of node") Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") # visiable after d0dc12e86b319 Signed-off-by: David Hildenbrand <david@redhat.com> Tested-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Keith Busch <keith.busch@intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Nayna Jain <nayna@linux.ibm.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-06mm/memory_hotplug: fix updating the node spanDavid Hildenbrand
We recently started updating the node span based on the zone span to avoid touching uninitialized memmaps. Currently, we will always detect the node span to start at 0, meaning a node can easily span too many pages. pgdat_is_empty() will still work correctly if all zones span no pages. We should skip over all zones without spanned pages and properly handle the first detected zone that spans pages. Unfortunately, in contrast to the zone span (/proc/zoneinfo), the node span cannot easily be inspected and tested. The node span gives no real guarantees when an architecture supports memory hotplug, meaning it can easily contain holes or span pages of different nodes. The node span is not really used after init on architectures that support memory hotplug. E.g., we use it in mm/memory_hotplug.c:try_offline_node() and in mm/kmemleak.c:kmemleak_scan(). These users seem to be fine. Link: http://lkml.kernel.org/r/20191027222714.5313-1-david@redhat.com Fixes: 00d6c019b5bc ("mm/memory_hotplug: don't access uninitialized memmaps in shrink_pgdat_span()") Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-10-19mm/memory_hotplug: don't access uninitialized memmaps in shrink_pgdat_span()David Hildenbrand
We might use the nid of memmaps that were never initialized. For example, if the memmap was poisoned, we will crash the kernel in pfn_to_nid() right now. Let's use the calculated boundaries of the separate zones instead. This now also avoids having to iterate over a whole bunch of subsections again, after shrinking one zone. Before commit d0dc12e86b31 ("mm/memory_hotplug: optimize memory hotplug"), the memmap was initialized to 0 and the node was set to the right value. After that commit, the node might be garbage. We'll have to fix shrink_zone_span() next. Link: http://lkml.kernel.org/r/20191006085646.5768-4-david@redhat.com Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [d0dc12e86b319] Signed-off-by: David Hildenbrand <david@redhat.com> Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Damian Tometzki <damian.tometzki@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Halil Pasic <pasic@linux.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jun Yao <yaojun8558363@gmail.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Pankaj Gupta <pagupta@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Pavel Tatashin <pavel.tatashin@microsoft.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qian Cai <cai@lca.pw> Cc: Rich Felker <dalias@libc.org> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Steve Capper <steve.capper@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Yu Zhao <yuzhao@google.com> Cc: <stable@vger.kernel.org> [4.13+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24mm/memory_hotplug.c: s/is/ifSouptick Joarder
Correct typo in comment. Link: http://lkml.kernel.org/r/1568233954-3913-1-git-send-email-jrdr.linux@gmail.com Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24mm/memory_hotplug: online_pages cannot be 0 in online_pages()David Hildenbrand
walk_system_ram_range() will fail with -EINVAL in case online_pages_range() was never called (== no resource applicable in the range). Otherwise, we will always call online_pages_range() with nr_pages > 0 and, therefore, have online_pages > 0. Remove that special handling. Link: http://lkml.kernel.org/r/20190814154109.3448-6-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Arun KS <arunks@codeaurora.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov <bp@suse.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Nadav Amit <namit@vmware.com> Cc: Wei Yang <richardw.yang@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24mm/memory_hotplug: make sure the pfn is aligned to the order when onliningDavid Hildenbrand
Commit a9cd410a3d29 ("mm/page_alloc.c: memory hotplug: free pages as higher order") assumed that any PFN we get via memory resources is aligned to to MAX_ORDER - 1, I am not convinced that is always true. Let's play safe, check the alignment and fallback to single pages. akpm: warn in this situation so we get to find out if and why this ever occurs. [akpm@linux-foundation.org: add WARN_ON_ONCE()] Link: http://lkml.kernel.org/r/20190814154109.3448-5-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Arun KS <arunks@codeaurora.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov <bp@suse.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Nadav Amit <namit@vmware.com> Cc: Wei Yang <richardw.yang@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24mm/memory_hotplug: simplify online_pages_range()David Hildenbrand
online_pages always corresponds to nr_pages. Simplify the code, getting rid of online_pages_blocks(). Add some comments. Link: http://lkml.kernel.org/r/20190814154109.3448-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Arun KS <arunks@codeaurora.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov <bp@suse.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Nadav Amit <namit@vmware.com> Cc: Wei Yang <richardw.yang@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24mm/memory_hotplug: drop PageReserved() check in online_pages_range()David Hildenbrand
move_pfn_range_to_zone() will set all pages to PG_reserved via memmap_init_zone(). The only way a page could no longer be reserved would be if a MEM_GOING_ONLINE notifier would clear PG_reserved - which is not done (the online_page callback is used for that purpose by e.g., Hyper-V instead). walk_system_ram_range() will never call online_pages_range() with duplicate PFNs, so drop the PageReserved() check. This seems to be a leftover from ancient times where the memmap was initialized when adding memory and we wanted to check for already onlined memory. Link: http://lkml.kernel.org/r/20190814154109.3448-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Arun KS <arunks@codeaurora.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov <bp@suse.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Nadav Amit <namit@vmware.com> Cc: Wei Yang <richardw.yang@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24mm/memory_hotplug.c: prevent memory leak when reusing pgdatWei Yang
When offlining a node in try_offline_node(), pgdat is not released. So that pgdat could be reused in hotadd_new_pgdat(). While we reallocate pgdat->per_cpu_nodestats if this pgdat is reused. This patch prevents the memory leak by just allocating per_cpu_nodestats when it is a new pgdat. Link: http://lkml.kernel.org/r/20190813020608.10194-1-richardw.yang@linux.intel.com Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <OSalvador@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24drivers/base/memory.c: don't store end_section_nr in memory blocksDavid Hildenbrand
Each memory block spans the same amount of sections/pages/bytes. The size is determined before the first memory block is created. No need to store what we can easily calculate - and the calculations even look simpler now. Michal brought up the idea of variable-sized memory blocks. However, if we ever implement something like this, we will need an API compatibility switch and reworks at various places (most code assumes a fixed memory block size). So let's cleanup what we have right now. While at it, fix the variable naming in register_mem_sect_under_node() - we no longer talk about a single section. Link: http://lkml.kernel.org/r/20190809110200.2746-1-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24mm/memory_hotplug: remove move_pfn_range()David Hildenbrand
Let's remove this indirection. We need the zone in the caller either way, so let's just detect it there. Add some documentation for move_pfn_range_to_zone() instead. [akpm@linux-foundation.org: restore newline, per David] Link: http://lkml.kernel.org/r/20190724142324.3686-1-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: David Hildenbrand <david@redhat.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24mm: introduce compound_nr()Matthew Wilcox (Oracle)
Replace 1 << compound_order(page) with compound_nr(page). Minor improvements in readability. Link: http://lkml.kernel.org/r/20190721104612.19120-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-03mm/memory_hotplug.c: remove unneeded return for void functionWeitao Hou
return is unneeded in void function Link: http://lkml.kernel.org/r/20190723130814.21826-1-houweitaoo@gmail.com Signed-off-by: Weitao Hou <houweitaoo@gmail.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/sparsemem: cleanup 'section number' data typesDan Williams
David points out that there is a mixture of 'int' and 'unsigned long' usage for section number data types. Update the memory hotplug path to use 'unsigned long' consistently for section numbers. [akpm@linux-foundation.org: fix printk format] Link: http://lkml.kernel.org/r/156107543656.1329419.11505835211949439815.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reported-by: David Hildenbrand <david@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/sparsemem: support sub-section hotplugDan Williams
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 <dan.j.williams@intel.com> Signed-off-by: Oscar Salvador <osalvador@suse.de> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64] Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/sparsemem: prepare for sub-section rangesDan Williams
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 <dan.j.williams@intel.com> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64] Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/hotplug: kill is_dev_zone() usage in __remove_pages()Dan Williams
The zone type check was a leftover from the cleanup that plumbed altmap through the memory hotplug path, i.e. commit da024512a1fa "mm: pass the vmem_altmap to arch_remove_memory and __remove_pages". Link: http://lkml.kernel.org/r/156092352642.979959.6664333788149363039.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64] Cc: Michal Hocko <mhocko@suse.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/hotplug: prepare shrink_{zone, pgdat}_span for sub-section removalDan Williams
Sub-section hotplug support reduces the unit of operation of hotplug from section-sized-units (PAGES_PER_SECTION) to sub-section-sized units (PAGES_PER_SUBSECTION). Teach shrink_{zone,pgdat}_span() to consider PAGES_PER_SUBSECTION boundaries as the points where pfn_valid(), not valid_section(), can toggle. [osalvador@suse.de: fix shrink_{zone,node}_span] Link: http://lkml.kernel.org/r/20190717090725.23618-3-osalvador@suse.de Link: http://lkml.kernel.org/r/156092351496.979959.12703722803097017492.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64] Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/sparsemem: introduce struct mem_section_usageDan Williams
Patch series "mm: Sub-section memory hotplug support", v10. The memory hotplug section is an arbitrary / convenient unit for memory hotplug. 'Section-size' units have bled into the user interface ('memblock' sysfs) and can not be changed without breaking existing userspace. The section-size constraint, while mostly benign for typical memory hotplug, has and continues to wreak havoc with 'device-memory' use cases, persistent memory (pmem) in particular. Recall that pmem uses devm_memremap_pages(), and subsequently arch_add_memory(), to allocate a 'struct page' memmap for pmem. However, it does not use the 'bottom half' of memory hotplug, i.e. never marks pmem pages online and never exposes the userspace memblock interface for pmem. This leaves an opening to redress the section-size constraint. To date, the libnvdimm subsystem has attempted to inject padding to satisfy the internal constraints of arch_add_memory(). Beyond complicating the code, leading to bugs [2], wasting memory, and limiting configuration flexibility, the padding hack is broken when the platform changes this physical memory alignment of pmem from one boot to the next. Device failure (intermittent or permanent) and physical reconfiguration are events that can cause the platform firmware to change the physical placement of pmem on a subsequent boot, and device failure is an everyday event in a data-center. It turns out that sections are only a hard requirement of the user-facing interface for memory hotplug and with a bit more infrastructure sub-section arch_add_memory() support can be added for kernel internal usages like devm_memremap_pages(). Here is an analysis of the current design assumptions in the current code and how they are addressed in the new implementation: Current design assumptions: - Sections that describe boot memory (early sections) are never unplugged / removed. - pfn_valid(), in the CONFIG_SPARSEMEM_VMEMMAP=y, case devolves to a valid_section() check - __add_pages() and helper routines assume all operations occur in PAGES_PER_SECTION units. - The memblock sysfs interface only comprehends full sections New design assumptions: - Sections are instrumented with a sub-section bitmask to track (on x86) individual 2MB sub-divisions of a 128MB section. - Partially populated early sections can be extended with additional sub-sections, and those sub-sections can be removed with arch_remove_memory(). With this in place we no longer lose usable memory capacity to padding. - pfn_valid() is updated to look deeper than valid_section() to also check the active-sub-section mask. This indication is in the same cacheline as the valid_section() so the performance impact is expected to be negligible. So far the lkp robot has not reported any regressions. - Outside of the core vmemmap population routines which are replaced, other helper routines like shrink_{zone,pgdat}_span() are updated to handle the smaller granularity. Core memory hotplug routines that deal with online memory are not touched. - The existing memblock sysfs user api guarantees / assumptions are not touched since this capability is limited to !online !memblock-sysfs-accessible sections. Meanwhile the issue reports continue to roll in from users that do not understand when and how the 128MB constraint will bite them. The current implementation relied on being able to support at least one misaligned namespace, but that immediately falls over on any moderately complex namespace creation attempt. Beyond the initial problem of 'System RAM' colliding with pmem, and the unsolvable problem of physical alignment changes, Linux is now being exposed to platforms that collide pmem ranges with other pmem ranges by default [3]. In short, devm_memremap_pages() has pushed the venerable section-size constraint past the breaking point, and the simplicity of section-aligned arch_add_memory() is no longer tenable. These patches are exposed to the kbuild robot on a subsection-v10 branch [4], and a preview of the unit test for this functionality is available on the 'subsection-pending' branch of ndctl [5]. [2]: https://lore.kernel.org/r/155000671719.348031.2347363160141119237.stgit@dwillia2-desk3.amr.corp.intel.com [3]: https://github.com/pmem/ndctl/issues/76 [4]: https://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm.git/log/?h=subsection-v10 [5]: https://github.com/pmem/ndctl/commit/7c59b4867e1c This patch (of 13): Towards enabling memory hotplug to track partial population of a section, introduce 'struct mem_section_usage'. A pointer to a 'struct mem_section_usage' instance replaces the existing pointer to a 'pageblock_flags' bitmap. Effectively it adds one more 'unsigned long' beyond the 'pageblock_flags' (usemap) allocation to house a new 'subsection_map' bitmap. The new bitmap enables the memory hot{plug,remove} implementation to act on incremental sub-divisions of a section. SUBSECTION_SHIFT is defined as global constant instead of per-architecture value like SECTION_SIZE_BITS in order to allow cross-arch compatibility of subsection users. Specifically a common subsection size allows for the possibility that persistent memory namespace configurations be made compatible across architectures. The primary motivation for this functionality is to support platforms that mix "System RAM" and "Persistent Memory" within a single section, or multiple PMEM ranges with different mapping lifetimes within a single section. The section restriction for hotplug has caused an ongoing saga of hacks and bugs for devm_memremap_pages() users. Beyond the fixups to teach existing paths how to retrieve the 'usemap' from a section, and updates to usemap allocation path, there are no expected behavior changes. Link: http://lkml.kernel.org/r/156092349845.979959.73333291612799019.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Wei Yang <richardw.yang@linux.intel.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64] Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Qian Cai <cai@lca.pw> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/memory_hotplug: move and simplify walk_memory_blocks()David Hildenbrand
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 <david@redhat.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Andrew Banman <andrew.banman@hpe.com> Cc: Mike Travis <mike.travis@hpe.com> Cc: Oscar Salvador <osalvador@suse.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Arun KS <arunks@codeaurora.org> Cc: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/memory_hotplug: rename walk_memory_range() and pass start+size instead of ↵David Hildenbrand
pfns 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 <david@redhat.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Len Brown <lenb@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: David Hildenbrand <david@redhat.com> Cc: Rashmica Gupta <rashmica.g@gmail.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Michael Neuling <mikey@neuling.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Juergen Gross <jgross@suse.com> Cc: Qian Cai <cai@lca.pw> Cc: Arun KS <arunks@codeaurora.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/memory_hotplug: remove "zone" parameter from sparse_remove_one_sectionDavid Hildenbrand
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 <david@redhat.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Wei Yang <richardw.yang@linux.intel.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: Andrew Banman <andrew.banman@hpe.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Arun KS <arunks@codeaurora.org> Cc: Baoquan He <bhe@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chintan Pandya <cpandya@codeaurora.org> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Jun Yao <yaojun8558363@gmail.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Mark Brown <broonie@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Mathieu Malaterre <malat@debian.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: "mike.travis@hpe.com" <mike.travis@hpe.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qian Cai <cai@lca.pw> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Rich Felker <dalias@libc.org> Cc: Rob Herring <robh@kernel.org> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/memory_hotplug: remove memory block devices before arch_remove_memory()David Hildenbrand
Let's factor out removing of memory block devices, which is only necessary for memory added via add_memory() and friends that created memory block devices. Remove the devices before calling arch_remove_memory(). This finishes factoring out memory block device handling from arch_add_memory() and arch_remove_memory(). Link: http://lkml.kernel.org/r/20190527111152.16324-10-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: "mike.travis@hpe.com" <mike.travis@hpe.com> Cc: Andrew Banman <andrew.banman@hpe.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Mark Brown <broonie@kernel.org> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Oscar Salvador <osalvador@suse.de> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Arun KS <arunks@codeaurora.org> Cc: Mathieu Malaterre <malat@debian.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Baoquan He <bhe@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chintan Pandya <cpandya@codeaurora.org> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Jun Yao <yaojun8558363@gmail.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qian Cai <cai@lca.pw> Cc: Rich Felker <dalias@libc.org> Cc: Rob Herring <robh@kernel.org> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/memory_hotplug: drop MHP_MEMBLOCK_APIDavid Hildenbrand
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 <david@redhat.com> Reviewed-by: Wei Yang <richardw.yang@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <david@redhat.com> Cc: Oscar Salvador <osalvador@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Qian Cai <cai@lca.pw> Cc: Arun KS <arunks@codeaurora.org> Cc: Mathieu Malaterre <malat@debian.org> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: Andrew Banman <andrew.banman@hpe.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Baoquan He <bhe@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chintan Pandya <cpandya@codeaurora.org> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Jun Yao <yaojun8558363@gmail.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Mark Brown <broonie@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: "mike.travis@hpe.com" <mike.travis@hpe.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Rich Felker <dalias@libc.org> Cc: Rob Herring <robh@kernel.org> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/memory_hotplug: create memory block devices after arch_add_memory()David Hildenbrand
Only memory to be added to the buddy and to be onlined/offlined by user space using /sys/devices/system/memory/... needs (and should have!) memory block devices. Factor out creation of memory block devices. Create all devices after arch_add_memory() succeeded. We can later drop the want_memblock parameter, because it is now effectively stale. Only after memory block devices have been added, memory can be onlined by user space. This implies, that memory is not visible to user space at all before arch_add_memory() succeeded. While at it - use WARN_ON_ONCE instead of BUG_ON in moved unregister_memory() - introduce find_memory_block_by_id() to search via block id - Use find_memory_block_by_id() in init_memory_block() to catch duplicates Link: http://lkml.kernel.org/r/20190527111152.16324-8-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: "mike.travis@hpe.com" <mike.travis@hpe.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Banman <andrew.banman@hpe.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Qian Cai <cai@lca.pw> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Arun KS <arunks@codeaurora.org> Cc: Mathieu Malaterre <malat@debian.org> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Baoquan He <bhe@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chintan Pandya <cpandya@codeaurora.org> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Jun Yao <yaojun8558363@gmail.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Mark Brown <broonie@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rich Felker <dalias@libc.org> Cc: Rob Herring <robh@kernel.org> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/memory_hotplug: allow arch_remove_memory() without CONFIG_MEMORY_HOTREMOVEDavid Hildenbrand
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 <david@redhat.com> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <david@redhat.com> Cc: Oscar Salvador <osalvador@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Mark Brown <broonie@kernel.org> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Rob Herring <robh@kernel.org> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: "mike.travis@hpe.com" <mike.travis@hpe.com> Cc: Andrew Banman <andrew.banman@hpe.com> Cc: Arun KS <arunks@codeaurora.org> Cc: Qian Cai <cai@lca.pw> Cc: Mathieu Malaterre <malat@debian.org> Cc: Baoquan He <bhe@redhat.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chintan Pandya <cpandya@codeaurora.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Jun Yao <yaojun8558363@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18mm/memory_hotplug: simplify and fix check_hotplug_memory_range()David Hildenbrand
Patch series "mm/memory_hotplug: Factor out memory block devicehandling", v3. We only want memory block devices for memory to be onlined/offlined (add/remove from the buddy). This is required so user space can online/offline memory and kdump gets notified about newly onlined memory. Let's factor out creation/removal of memory block devices. This helps to further cleanup arch_add_memory/arch_remove_memory() and to make implementation of new features easier - especially sub-section memory hot add from Dan. Anshuman Khandual is currently working on arch_remove_memory(). I added a temporary solution via "arm64/mm: Add temporary arch_remove_memory() implementation", that is sufficient as a firsts tep in the context of this series. (we don't cleanup page tables in case anything goes wrong already) Did a quick sanity test with DIMM plug/unplug, making sure all devices and sysfs links properly get added/removed. Compile tested on s390x and x86-64. This patch (of 11): By converting start and size to page granularity, we actually ignore unaligned parts within a page instead of properly bailing out with an error. Link: http://lkml.kernel.org/r/20190527111152.16324-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Wei Yang <richardw.yang@linux.intel.com> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <david@redhat.com> Cc: Qian Cai <cai@lca.pw> Cc: Arun KS <arunks@codeaurora.org> Cc: Mathieu Malaterre <malat@debian.org> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: Andrew Banman <andrew.banman@hpe.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Baoquan He <bhe@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chintan Pandya <cpandya@codeaurora.org> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Jun Yao <yaojun8558363@gmail.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Mark Brown <broonie@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: "mike.travis@hpe.com" <mike.travis@hpe.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Rich Felker <dalias@libc.org> Cc: Rob Herring <robh@kernel.org> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-16mm/hotplug: make remove_memory() interface usablePavel Tatashin
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 <pasha.tatashin@soleen.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov <bp@suse.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: James Morris <jmorris@namei.org> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Ross Zwisler <zwisler@kernel.org> Cc: Sasha Levin <sashal@kernel.org> Cc: Takashi Iwai <tiwai@suse.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-02memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flagChristoph Hellwig
Add a flags field to struct dev_pagemap to replace the altmap_valid boolean to be a little more extensible. Also add a pgmap_altmap() helper to find the optional altmap and clean up the code using the altmap using it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-05-21treewide: Add SPDX license identifier for missed filesThomas Gleixner
Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14mm: shuffle initial free memory to improve memory-side-cache utilizationDan Williams
Patch series "mm: Randomize free memory", v10. This patch (of 3): Randomization of the page allocator improves the average utilization of a direct-mapped memory-side-cache. Memory side caching is a platform capability that Linux has been previously exposed to in HPC (high-performance computing) environments on specialty platforms. In that instance it was a smaller pool of high-bandwidth-memory relative to higher-capacity / lower-bandwidth DRAM. Now, this capability is going to be found on general purpose server platforms where DRAM is a cache in front of higher latency persistent memory [1]. Robert offered an explanation of the state of the art of Linux interactions with memory-side-caches [2], and I copy it here: It's been a problem in the HPC space: http://www.nersc.gov/research-and-development/knl-cache-mode-performance-coe/ A kernel module called zonesort is available to try to help: https://software.intel.com/en-us/articles/xeon-phi-software and this abandoned patch series proposed that for the kernel: https://lkml.kernel.org/r/20170823100205.17311-1-lukasz.daniluk@intel.com Dan's patch series doesn't attempt to ensure buffers won't conflict, but also reduces the chance that the buffers will. This will make performance more consistent, albeit slower than "optimal" (which is near impossible to attain in a general-purpose kernel). That's better than forcing users to deploy remedies like: "To eliminate this gradual degradation, we have added a Stream measurement to the Node Health Check that follows each job; nodes are rebooted whenever their measured memory bandwidth falls below 300 GB/s." A replacement for zonesort was merged upstream in commit cc9aec03e58f ("x86/numa_emulation: Introduce uniform split capability"). With this numa_emulation capability, memory can be split into cache sized ("near-memory" sized) numa nodes. A bind operation to such a node, and disabling workloads on other nodes, enables full cache performance. However, once the workload exceeds the cache size then cache conflicts are unavoidable. While HPC environments might be able to tolerate time-scheduling of cache sized workloads, for general purpose server platforms, the oversubscribed cache case will be the common case. The worst case scenario is that a server system owner benchmarks a workload at boot with an un-contended cache only to see that performance degrade over time, even below the average cache performance due to excessive conflicts. Randomization clips the peaks and fills in the valleys of cache utilization to yield steady average performance. Here are some performance impact details of the patches: 1/ An Intel internal synthetic memory bandwidth measurement tool, saw a 3X speedup in a contrived case that tries to force cache conflicts. The contrived cased used the numa_emulation capability to force an instance of the benchmark to be run in two of the near-memory sized numa nodes. If both instances were placed on the same emulated they would fit and cause zero conflicts. While on separate emulated nodes without randomization they underutilized the cache and conflicted unnecessarily due to the in-order allocation per node. 2/ A well known Java server application benchmark was run with a heap size that exceeded cache size by 3X. The cache conflict rate was 8% for the first run and degraded to 21% after page allocator aging. With randomization enabled the rate levelled out at 11%. 3/ A MongoDB workload did not observe measurable difference in cache-conflict rates, but the overall throughput dropped by 7% with randomization in one case. 4/ Mel Gorman ran his suite of performance workloads with randomization enabled on platforms without a memory-side-cache and saw a mix of some improvements and some losses [3]. While there is potentially significant improvement for applications that depend on low latency access across a wide working-set, the performance may be negligible to negative for other workloads. For this reason the shuffle capability defaults to off unless a direct-mapped memory-side-cache is detected. Even then, the page_alloc.shuffle=0 parameter can be specified to disable the randomization on those systems. Outside of memory-side-cache utilization concerns there is potentially security benefit from randomization. Some data exfiltration and return-oriented-programming attacks rely on the ability to infer the location of sensitive data objects. The kernel page allocator, especially early in system boot, has predictable first-in-first out behavior for physical pages. Pages are freed in physical address order when first onlined. Quoting Kees: "While we already have a base-address randomization (CONFIG_RANDOMIZE_MEMORY), attacks against the same hardware and memory layouts would certainly be using the predictability of allocation ordering (i.e. for attacks where the base address isn't important: only the relative positions between allocated memory). This is common in lots of heap-style attacks. They try to gain control over ordering by spraying allocations, etc. I'd really like to see this because it gives us something similar to CONFIG_SLAB_FREELIST_RANDOM but for the page allocator." While SLAB_FREELIST_RANDOM reduces the predictability of some local slab caches it leaves vast bulk of memory to be predictably in order allocated. However, it should be noted, the concrete security benefits are hard to quantify, and no known CVE is mitigated by this randomization. Introduce shuffle_free_memory(), and its helper shuffle_zone(), to perform a Fisher-Yates shuffle of the page allocator 'free_area' lists when they are initially populated with free memory at boot and at hotplug time. Do this based on either the presence of a page_alloc.shuffle=Y command line parameter, or autodetection of a memory-side-cache (to be added in a follow-on patch). The shuffling is done in terms of CONFIG_SHUFFLE_PAGE_ORDER sized free pages where the default CONFIG_SHUFFLE_PAGE_ORDER is MAX_ORDER-1 i.e. 10, 4MB this trades off randomization granularity for time spent shuffling. MAX_ORDER-1 was chosen to be minimally invasive to the page allocator while still showing memory-side cache behavior improvements, and the expectation that the security implications of finer granularity randomization is mitigated by CONFIG_SLAB_FREELIST_RANDOM. The performance impact of the shuffling appears to be in the noise compared to other memory initialization work. This initial randomization can be undone over time so a follow-on patch is introduced to inject entropy on page free decisions. It is reasonable to ask if the page free entropy is sufficient, but it is not enough due to the in-order initial freeing of pages. At the start of that process putting page1 in front or behind page0 still keeps them close together, page2 is still near page1 and has a high chance of being adjacent. As more pages are added ordering diversity improves, but there is still high page locality for the low address pages and this leads to no significant impact to the cache conflict rate. [1]: https://itpeernetwork.intel.com/intel-optane-dc-persistent-memory-operating-modes/ [2]: https://lkml.kernel.org/r/AT5PR8401MB1169D656C8B5E121752FC0F8AB120@AT5PR8401MB1169.NAMPRD84.PROD.OUTLOOK.COM [3]: https://lkml.org/lkml/2018/10/12/309 [dan.j.williams@intel.com: fix shuffle enable] Link: http://lkml.kernel.org/r/154943713038.3858443.4125180191382062871.stgit@dwillia2-desk3.amr.corp.intel.com [cai@lca.pw: fix SHUFFLE_PAGE_ALLOCATOR help texts] Link: http://lkml.kernel.org/r/20190425201300.75650-1-cai@lca.pw Link: http://lkml.kernel.org/r/154899811738.3165233.12325692939590944259.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Qian Cai <cai@lca.pw> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Robert Elliott <elliott@hpe.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14mm/memory_hotplug: make __remove_pages() and arch_remove_memory() never failDavid Hildenbrand
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 <david@redhat.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Oscar Salvador <osalvador@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Stefan Agner <stefan@agner.ch> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Arun KS <arunks@codeaurora.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Rob Herring <robh@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Qian Cai <cai@lca.pw> Cc: Mathieu Malaterre <malat@debian.org> Cc: Andrew Banman <andrew.banman@hpe.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Mike Travis <mike.travis@hpe.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14mm/memory_hotplug: make __remove_section() never failDavid Hildenbrand
Let's just warn in case a section is not valid instead of failing to remove somewhere in the middle of the process, returning an error that will be mostly ignored by callers. Link: http://lkml.kernel.org/r/20190409100148.24703-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <david@redhat.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Qian Cai <cai@lca.pw> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Arun KS <arunks@codeaurora.org> Cc: Mathieu Malaterre <malat@debian.org> Cc: Andrew Banman <andrew.banman@hpe.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Mike Travis <mike.travis@hpe.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Rich Felker <dalias@libc.org> Cc: Rob Herring <robh@kernel.org> Cc: Stefan Agner <stefan@agner.ch> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14mm/memory_hotplug: make unregister_memory_section() never failDavid Hildenbrand
Failing while removing memory is mostly ignored and cannot really be handled. Let's treat errors in unregister_memory_section() in a nice way, warning, but continuing. Link: http://lkml.kernel.org/r/20190409100148.24703-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Banman <andrew.banman@hpe.com> Cc: Mike Travis <mike.travis@hpe.com> Cc: David Hildenbrand <david@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Qian Cai <cai@lca.pw> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Arun KS <arunks@codeaurora.org> Cc: Mathieu Malaterre <malat@debian.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rich Felker <dalias@libc.org> Cc: Rob Herring <robh@kernel.org> Cc: Stefan Agner <stefan@agner.ch> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14mm/memory_hotplug: release memory resource after arch_remove_memory()David Hildenbrand
Patch series "mm/memory_hotplug: Better error handling when removing memory", v1. Error handling when removing memory is somewhat messed up right now. Some errors result in warnings, others are completely ignored. Memory unplug code can essentially not deal with errors properly as of now. remove_memory() will never fail. We have basically two choices: 1. Allow arch_remov_memory() and friends to fail, propagating errors via remove_memory(). Might be problematic (e.g. DIMMs consisting of multiple pieces added/removed separately). 2. Don't allow the functions to fail, handling errors in a nicer way. It seems like most errors that can theoretically happen are really corner cases and mostly theoretical (e.g. "section not valid"). However e.g. aborting removal of sections while all callers simply continue in case of errors is not nice. If we can gurantee that removal of memory always works (and WARN/skip in case of theoretical errors so we can figure out what is going on), we can go ahead and implement better error handling when adding memory. E.g. via add_memory(): arch_add_memory() ret = do_stuff() if (ret) { arch_remove_memory(); goto error; } Handling here that arch_remove_memory() might fail is basically impossible. So I suggest, let's avoid reporting errors while removing memory, warning on theoretical errors instead and continuing instead of aborting. This patch (of 4): __add_pages() doesn't add the memory resource, so __remove_pages() shouldn't remove it. Let's factor it out. Especially as it is a special case for memory used as system memory, added via add_memory() and friends. We now remove the resource after removing the sections instead of doing it the other way around. I don't think this change is problematic. add_memory() register memory resource arch_add_memory() remove_memory arch_remove_memory() release memory resource While at it, explain why we ignore errors and that it only happeny if we remove memory in a different granularity as we added it. [david@redhat.com: fix printk warning] Link: http://lkml.kernel.org/r/20190417120204.6997-1-david@redhat.com Link: http://lkml.kernel.org/r/20190409100148.24703-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <david@redhat.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Qian Cai <cai@lca.pw> Cc: Arun KS <arunks@codeaurora.org> Cc: Mathieu Malaterre <malat@debian.org> Cc: Andrew Banman <andrew.banman@hpe.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Mike Travis <mike.travis@hpe.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Rich Felker <dalias@libc.org> Cc: Rob Herring <robh@kernel.org> Cc: Stefan Agner <stefan@agner.ch> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14mm, memory_hotplug: provide a more generic restrictions for memory hotplugMichal Hocko
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 <mhocko@suse.com> Signed-off-by: Oscar Salvador <osalvador@suse.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14mm, memory_hotplug: cleanup memory offline pathMichal Hocko
check_pages_isolated_cb currently accounts the whole pfn range as being offlined if test_pages_isolated suceeds on the range. This is based on the assumption that all pages in the range are freed which is currently the case in most cases but it won't be with later changes, as pages marked as vmemmap won't be isolated. Move the offlined pages counting to offline_isolated_pages_cb and rely on __offline_isolated_pages to return the correct value. check_pages_isolated_cb will still do it's primary job and check the pfn range. While we are at it remove check_pages_isolated and offline_isolated_pages and use directly walk_system_ram_range as do in online_pages. Link: http://lkml.kernel.org/r/20190408082633.2864-2-osalvador@suse.de Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Oscar Salvador <osalvador@suse.de> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14mm/memory_hotplug.c: fix the wrong usage of N_HIGH_MEMORYBaoquan He
In node_states_check_changes_online(), N_HIGH_MEMORY is used to substitute ZONE_HIGHMEM directly. This is not right. N_HIGH_MEMORY is to mark the memory state of node. Here zone index is checked, which should be compared with 'ZONE_HIGHMEM' accordingly. Replace it with ZONE_HIGHMEM. This is a code cleanup - no known runtime effects. Link: http://lkml.kernel.org/r/20190320080732.14933-1-bhe@redhat.com Fixes: 8efe33f40f3e ("mm/memory_hotplug.c: simplify node_states_check_changes_online") Signed-off-by: Baoquan He <bhe@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14mm,memory_hotplug: drop redundant hugepage_migration_supported checkOscar Salvador
has_unmovable_pages() already checks whether the hugetlb page supports migration, so all non-migratable hugetlb pages should have been caught there. Let us drop the check from scan_movable_pages() as is redundant. Link: http://lkml.kernel.org/r/20190320152658.10855-3-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14mm,memory_hotplug: unlock 1GB-hugetlb on x86_64Oscar Salvador
On x86_64, 1GB-hugetlb pages could never be offlined due to the fact that hugepage_migration_supported() returned false for PUD_SHIFT. So whenever we wanted to offline a memblock containing a gigantic hugetlb page, we never got beyond has_unmovable_pages() check. This changed with [1], where now we also return true for PUD_SHIFT. After that patch, the check in has_unmovable_pages() and scan_movable_pages() returned true, but we still had a final barrier in do_migrate_range(): if (compound_order(head) > PFN_SECTION_SHIFT) { ret = -EBUSY; break; } This is not really nice, and we do not really need it. It is perfectly possible to migrate a gigantic page as long as another node has a spare gigantic page for us. In alloc_huge_page_nodemask(), we calculate the __real__ number of free pages, and if any, we try to dequeue one from another node. This all works fine when we do have another node with a spare gigantic page, but if that is not the case, alloc_huge_page_nodemask() ends up calling alloc_migrate_huge_page() which bails out if the wanted page is gigantic. That is mainly because finding a 1GB (or even 16GB on powerpc) contiguous memory is quite unlikely when the system has been running for a while. In that situation, we will keep looping forever because scan_movable_pages() will give us the same page and we will fail again because there is no node where we can dequeue a gigantic page from. This is not nice, and it has been raised that we might want to treat -ENOMEM as a fatal error in do_migrate_range(), but this has to be checked further. Anyway, I would tend say that this is the administrator's job, to make sure that the system can keep up with the memory to be offlined, so that would mean that if we want to use gigantic pages, make sure that the other nodes have at least enough gigantic pages to keep up in case we need to offline memory. Just for the sake of completeness, this is one of the tests done: # echo 1 > /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/nr_hugepages # echo 1 > /sys/devices/system/node/node2/hugepages/hugepages-1048576kB/nr_hugepages # cat /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/nr_hugepages 1 # cat /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/free_hugepages 1 # cat /sys/devices/system/node/node2/hugepages/hugepages-1048576kB/nr_hugepages 1 # cat /sys/devices/system/node/node2/hugepages/hugepages-1048576kB/free_hugepages 1 (hugetlb1gb is a program that maps 1GB region using MAP_HUGE_1GB) # numactl -m 1 ./hugetlb1gb # cat /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/free_hugepages 0 # cat /sys/devices/system/node/node2/hugepages/hugepages-1048576kB/free_hugepages 1 # offline node1 memory # cat /sys/devices/system/node/node2/hugepages/hugepages-1048576kB/free_hugepages 0 [1] https://lore.kernel.org/patchwork/patch/998796/ Link: http://lkml.kernel.org/r/20190320152658.10855-2-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <david@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>