kernel.git/mm/Kconfig, branch linux-4.18.y

mm: disable deferred struct page for 32-bit arches

2018-09-29T09:55:57Z

commit 889c695d419f19e5db52592dafbaf26143c36d1f upstream. Deferred struct page init is needed only on systems with large amount of physical memory to improve boot performance. 32-bit systems do not benefit from this feature. Jiri reported a problem where deferred struct pages do not work well with x86-32: [ 0.035162] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes) [ 0.035725] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes) [ 0.036269] Initializing CPU#0 [ 0.036513] Initializing HighMem for node 0 (00036ffe:0007ffe0) [ 0.038459] page:f6780000 is uninitialized and poisoned [ 0.038460] raw: ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff [ 0.039509] page dumped because: VM_BUG_ON_PAGE(1 && PageCompound(page)) [ 0.040038] ------------[ cut here ]------------ [ 0.040399] kernel BUG at include/linux/page-flags.h:293! [ 0.040823] invalid opcode: 0000 [#1] SMP PTI [ 0.041166] CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.0-rc1_pt_jiri #9 [ 0.041694] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-20171110_100015-anatol 04/01/2014 [ 0.042496] EIP: free_highmem_page+0x64/0x80 [ 0.042839] Code: 13 46 d8 c1 e8 18 5d 83 e0 03 8d 04 c0 c1 e0 06 ff 80 ec 5f 44 d8 c3 8d b4 26 00 00 00 00 ba 08 65 28 d8 89 d8 e8 fc 71 02 00 <0f> 0b 8d 76 00 8d bc 27 00 00 00 00 ba d0 b1 26 d8 89 d8 e8 e4 71 [ 0.044338] EAX: 0000003c EBX: f6780000 ECX: 00000000 EDX: d856cbe8 [ 0.044868] ESI: 0007ffe0 EDI: d838df20 EBP: d838df00 ESP: d838defc [ 0.045372] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210086 [ 0.045913] CR0: 80050033 CR2: 00000000 CR3: 18556000 CR4: 00040690 [ 0.046413] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 0.046913] DR6: fffe0ff0 DR7: 00000400 [ 0.047220] Call Trace: [ 0.047419] add_highpages_with_active_regions+0xbd/0x10d [ 0.047854] set_highmem_pages_init+0x5b/0x71 [ 0.048202] mem_init+0x2b/0x1e8 [ 0.048460] start_kernel+0x1d2/0x425 [ 0.048757] i386_start_kernel+0x93/0x97 [ 0.049073] startup_32_smp+0x164/0x168 [ 0.049379] Modules linked in: [ 0.049626] ---[ end trace 337949378db0abbb ]--- We free highmem pages before their struct pages are initialized: mem_init() set_highmem_pages_init() add_highpages_with_active_regions() free_highmem_page() .. Access uninitialized struct page here.. Because there is no reason to have this feature on 32-bit systems, just disable it. Link: http://lkml.kernel.org/r/20180831150506.31246-1-pavel.tatashin@microsoft.com Fixes: 2e3ca40f03bb ("mm: relax deferred struct page requirements") Signed-off-by: Pavel Tatashin Reported-by: Jiri Slaby Acked-by: Michal Hocko Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm: make DEFERRED_STRUCT_PAGE_INIT explicitly depend on SPARSEMEM

2018-09-15T07:46:47Z

[ Upstream commit d39f8fb4b7776dcb09ec3bf7a321547083078ee3 ] The deferred memory initialization relies on section definitions, e.g PAGES_PER_SECTION, that are only available when CONFIG_SPARSEMEM=y on most architectures. Initially DEFERRED_STRUCT_PAGE_INIT depended on explicit ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT configuration option, but since the commit 2e3ca40f03bb13709df4 ("mm: relax deferred struct page requirements") this requirement was relaxed and now it is possible to enable DEFERRED_STRUCT_PAGE_INIT on architectures that support DISCONTINGMEM and NO_BOOTMEM which causes build failures. For instance, setting SMP=y and DEFERRED_STRUCT_PAGE_INIT=y on arc causes the following build failure: CC mm/page_alloc.o mm/page_alloc.c: In function 'update_defer_init': mm/page_alloc.c:321:14: error: 'PAGES_PER_SECTION' undeclared (first use in this function); did you mean 'USEC_PER_SEC'? (pfn & (PAGES_PER_SECTION - 1)) == 0) { ^~~~~~~~~~~~~~~~~ USEC_PER_SEC mm/page_alloc.c:321:14: note: each undeclared identifier is reported only once for each function it appears in In file included from include/linux/cache.h:5:0, from include/linux/printk.h:9, from include/linux/kernel.h:14, from include/asm-generic/bug.h:18, from arch/arc/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/mmdebug.h:5, from include/linux/mm.h:9, from mm/page_alloc.c:18: mm/page_alloc.c: In function 'deferred_grow_zone': mm/page_alloc.c:1624:52: error: 'PAGES_PER_SECTION' undeclared (first use in this function); did you mean 'USEC_PER_SEC'? unsigned long nr_pages_needed = ALIGN(1 << order, PAGES_PER_SECTION); ^ include/uapi/linux/kernel.h:11:47: note: in definition of macro '__ALIGN_KERNEL_MASK' #define __ALIGN_KERNEL_MASK(x, mask) (((x) + (mask)) & ~(mask)) ^~~~ include/linux/kernel.h:58:22: note: in expansion of macro '__ALIGN_KERNEL' #define ALIGN(x, a) __ALIGN_KERNEL((x), (a)) ^~~~~~~~~~~~~~ mm/page_alloc.c:1624:34: note: in expansion of macro 'ALIGN' unsigned long nr_pages_needed = ALIGN(1 << order, PAGES_PER_SECTION); ^~~~~ In file included from include/asm-generic/bug.h:18:0, from arch/arc/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/mmdebug.h:5, from include/linux/mm.h:9, from mm/page_alloc.c:18: mm/page_alloc.c: In function 'free_area_init_node': mm/page_alloc.c:6379:50: error: 'PAGES_PER_SECTION' undeclared (first use in this function); did you mean 'USEC_PER_SEC'? pgdat->static_init_pgcnt = min_t(unsigned long, PAGES_PER_SECTION, ^ include/linux/kernel.h:812:22: note: in definition of macro '__typecheck' (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1))) ^ include/linux/kernel.h:836:24: note: in expansion of macro '__safe_cmp' __builtin_choose_expr(__safe_cmp(x, y), \ ^~~~~~~~~~ include/linux/kernel.h:904:27: note: in expansion of macro '__careful_cmp' #define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <) ^~~~~~~~~~~~~ mm/page_alloc.c:6379:29: note: in expansion of macro 'min_t' pgdat->static_init_pgcnt = min_t(unsigned long, PAGES_PER_SECTION, ^~~~~ include/linux/kernel.h:836:2: error: first argument to '__builtin_choose_expr' not a constant __builtin_choose_expr(__safe_cmp(x, y), \ ^ include/linux/kernel.h:904:27: note: in expansion of macro '__careful_cmp' #define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <) ^~~~~~~~~~~~~ mm/page_alloc.c:6379:29: note: in expansion of macro 'min_t' pgdat->static_init_pgcnt = min_t(unsigned long, PAGES_PER_SECTION, ^~~~~ scripts/Makefile.build:317: recipe for target 'mm/page_alloc.o' failed Let's make the DEFERRED_STRUCT_PAGE_INIT explicitly depend on SPARSEMEM as the systems that support DISCONTIGMEM do not seem to have that huge amounts of memory that would make DEFERRED_STRUCT_PAGE_INIT relevant. Link: http://lkml.kernel.org/r/1530279308-24988-1-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport Acked-by: Michal Hocko Reviewed-by: Pavel Tatashin Tested-by: Randy Dunlap Cc: Pasha Tatashin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

Merge tag 'libnvdimm-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2018-06-09T00:21:52Z

Pull libnvdimm updates from Dan Williams: "This adds a user for the new 'bytes-remaining' updates to memcpy_mcsafe() that you already received through Ingo via the x86-dax- for-linus pull. Not included here, but still targeting this cycle, is support for handling memory media errors (poison) consumed via userspace dax mappings. Summary: - DAX broke a fundamental assumption of truncate of file mapped pages. The truncate path assumed that it is safe to disconnect a pinned page from a file and let the filesystem reclaim the physical block. With DAX the page is equivalent to the filesystem block. Introduce dax_layout_busy_page() to enable filesystems to wait for pinned DAX pages to be released. Without this wait a filesystem could allocate blocks under active device-DMA to a new file. - DAX arranges for the block layer to be bypassed and uses dax_direct_access() + copy_to_iter() to satisfy read(2) calls. However, the memcpy_mcsafe() facility is available through the pmem block driver. In order to safely handle media errors, via the DAX block-layer bypass, introduce copy_to_iter_mcsafe(). - Fix cache management policy relative to the ACPI NFIT Platform Capabilities Structure to properly elide cache flushes when they are not necessary. The table indicates whether CPU caches are power-fail protected. Clarify that a deep flush is always performed on REQ_{FUA,PREFLUSH} requests" * tag 'libnvdimm-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (21 commits) dax: Use dax_write_cache* helpers libnvdimm, pmem: Do not flush power-fail protected CPU caches libnvdimm, pmem: Unconditionally deep flush on *sync libnvdimm, pmem: Complete REQ_FLUSH => REQ_PREFLUSH acpi, nfit: Remove ecc_unit_size dax: dax_insert_mapping_entry always succeeds libnvdimm, e820: Register all pmem resources libnvdimm: Debug probe times linvdimm, pmem: Preserve read-only setting for pmem devices x86, nfit_test: Add unit test for memcpy_mcsafe() pmem: Switch to copy_to_iter_mcsafe() dax: Report bytes remaining in dax_iomap_actor() dax: Introduce a ->copy_to_iter dax operation uio, lib: Fix CONFIG_ARCH_HAS_UACCESS_MCSAFE compilation xfs, dax: introduce xfs_break_dax_layouts() xfs: prepare xfs_break_layouts() for another layout type xfs: prepare xfs_break_layouts() to be called with XFS_MMAPLOCK_EXCL mm, fs, dax: handle layout changes to pinned dax mappings mm: fix __gup_device_huge vs unmap mm: introduce MEMORY_DEVICE_FS_DAX and CONFIG_DEV_PAGEMAP_OPS ...

Merge branch 'for-4.18/dax' into libnvdimm-for-next

2018-06-08T22:16:40Z

mm: introduce ARCH_HAS_PTE_SPECIAL

2018-06-08T00:34:35Z

Currently the PTE special supports is turned on in per architecture header files. Most of the time, it is defined in arch/*/include/asm/pgtable.h depending or not on some other per architecture static definition. This patch introduce a new configuration variable to manage this directly in the Kconfig files. It would later replace __HAVE_ARCH_PTE_SPECIAL. Here notes for some architecture where the definition of __HAVE_ARCH_PTE_SPECIAL is not obvious: arm __HAVE_ARCH_PTE_SPECIAL which is currently defined in arch/arm/include/asm/pgtable-3level.h which is included by arch/arm/include/asm/pgtable.h when CONFIG_ARM_LPAE is set. So select ARCH_HAS_PTE_SPECIAL if ARM_LPAE. powerpc __HAVE_ARCH_PTE_SPECIAL is defined in 2 files: - arch/powerpc/include/asm/book3s/64/pgtable.h - arch/powerpc/include/asm/pte-common.h The first one is included if (PPC_BOOK3S & PPC64) while the second is included in all the other cases. So select ARCH_HAS_PTE_SPECIAL all the time. sparc: __HAVE_ARCH_PTE_SPECIAL is defined if defined(__sparc__) && defined(__arch64__) which are defined through the compiler in sparc/Makefile if !SPARC32 which I assume to be if SPARC64. So select ARCH_HAS_PTE_SPECIAL if SPARC64 There is no functional change introduced by this patch. Link: http://lkml.kernel.org/r/1523433816-14460-2-git-send-email-ldufour@linux.vnet.ibm.com Signed-off-by: Laurent Dufour Suggested-by: Jerome Glisse Reviewed-by: Jerome Glisse Acked-by: David Rientjes Cc: Michal Hocko Cc: "Aneesh Kumar K . V" Cc: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Jonathan Corbet Cc: Catalin Marinas Cc: Will Deacon Cc: Yoshinori Sato Cc: Rich Felker Cc: David S. Miller Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Vineet Gupta Cc: Palmer Dabbelt Cc: Albert Ou Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: David Rientjes Cc: Robin Murphy Cc: Christophe LEROY Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'docs-4.18' of git://git.lwn.net/linux

2018-06-04T19:34:27Z

Pull documentation updates from Jonathan Corbet: "There's been a fair amount of work in the docs tree this time around, including: - Extensive RST conversions and organizational work in the memory-management docs thanks to Mike Rapoport. - An update of Documentation/features from Andrea Parri and a script to keep it updated. - Various LICENSES updates from Thomas, along with a script to check SPDX tags. - Work to fix dangling references to documentation files; this involved a fair number of one-liner comment changes outside of Documentation/ ... and the usual list of documentation improvements, typo fixes, etc" * tag 'docs-4.18' of git://git.lwn.net/linux: (103 commits) Documentation: document hung_task_panic kernel parameter docs/admin-guide/mm: add high level concepts overview docs/vm: move ksm and transhuge from "user" to "internals" section. docs: Use the kerneldoc comments for memalloc_no*() doc: document scope NOFS, NOIO APIs docs: update kernel versions and dates in tables docs/vm: transhuge: split userspace bits to admin-guide/mm/transhuge docs/vm: transhuge: minor updates docs/vm: transhuge: change sections order Documentation: arm: clean up Marvell Berlin family info Documentation: gpio: driver: Fix a typo and some odd grammar docs: ranoops.rst: fix location of ramoops.txt scripts/documentation-file-ref-check: rewrite it in perl with auto-fix mode docs: uio-howto.rst: use a code block to solve a warning mm, THP, doc: Add document for thp_swpout/thp_swpout_fallback w1: w1_io.c: fix a kernel-doc warning Documentation/process/posting: wrap text at 80 cols docs: admin-guide: add cgroup-v2 documentation Revert "Documentation/features/vm: Remove arch support status file for 'pte_special'" Documentation: refcount-vs-atomic: Update reference to LKMM doc. ...

Merge tag 'dma-mapping-4.18' of git://git.infradead.org/users/hch/dma-mapping

2018-06-04T17:58:12Z

Pull dma-mapping updates from Christoph Hellwig: - replace the force_dma flag with a dma_configure bus method. (Nipun Gupta, although one patch is іncorrectly attributed to me due to a git rebase bug) - use GFP_DMA32 more agressively in dma-direct. (Takashi Iwai) - remove PCI_DMA_BUS_IS_PHYS and rely on the dma-mapping API to do the right thing for bounce buffering. - move dma-debug initialization to common code, and apply a few cleanups to the dma-debug code. - cleanup the Kconfig mess around swiotlb selection - swiotlb comment fixup (Yisheng Xie) - a trivial swiotlb fix. (Dan Carpenter) - support swiotlb on RISC-V. (based on a patch from Palmer Dabbelt) - add a new generic dma-noncoherent dma_map_ops implementation and use it for arc, c6x and nds32. - improve scatterlist validity checking in dma-debug. (Robin Murphy) - add a struct device quirk to limit the dma-mask to 32-bit due to bridge/system issues, and switch x86 to use it instead of a local hack for VIA bridges. - handle devices without a dma_mask more gracefully in the dma-direct code. * tag 'dma-mapping-4.18' of git://git.infradead.org/users/hch/dma-mapping: (48 commits) dma-direct: don't crash on device without dma_mask nds32: use generic dma_noncoherent_ops nds32: implement the unmap_sg DMA operation nds32: consolidate DMA cache maintainance routines x86/pci-dma: switch the VIA 32-bit DMA quirk to use the struct device flag x86/pci-dma: remove the explicit nodac and allowdac option x86/pci-dma: remove the experimental forcesac boot option Documentation/x86: remove a stray reference to pci-nommu.c core, dma-direct: add a flag 32-bit dma limits dma-mapping: remove unused gfp_t parameter to arch_dma_alloc_attrs dma-debug: check scatterlist segments c6x: use generic dma_noncoherent_ops arc: use generic dma_noncoherent_ops arc: fix arc_dma_{map,unmap}_page arc: fix arc_dma_sync_sg_for_{cpu,device} arc: simplify arc_dma_sync_single_for_{cpu,device} dma-mapping: provide a generic dma-noncoherent implementation dma-mapping: simplify Kconfig dependencies riscv: add swiotlb support riscv: only enable ZONE_DMA32 for 64-bit ...

mm: introduce MEMORY_DEVICE_FS_DAX and CONFIG_DEV_PAGEMAP_OPS

2018-05-22T13:59:39Z

In preparation for fixing dax-dma-vs-unmap issues, filesystems need to be able to rely on the fact that they will get wakeups on dev_pagemap page-idle events. Introduce MEMORY_DEVICE_FS_DAX and generic_dax_page_free() as common indicator / infrastructure for dax filesytems to require. With this change there are no users of the MEMORY_DEVICE_HOST designation, so remove it. The HMM sub-system extended dev_pagemap to arrange a callback when a dev_pagemap managed page is freed. Since a dev_pagemap page is free / idle when its reference count is 1 it requires an additional branch to check the page-type at put_page() time. Given put_page() is a hot-path we do not want to incur that check if HMM is not in use, so a static branch is used to avoid that overhead when not necessary. Now, the FS_DAX implementation wants to reuse this mechanism for receiving dev_pagemap ->page_free() callbacks. Rework the HMM-specific static-key into a generic mechanism that either HMM or FS_DAX code paths can enable. For ARCH=um builds, and any other arch that lacks ZONE_DEVICE support, care must be taken to compile out the DEV_PAGEMAP_OPS infrastructure. However, we still need to support FS_DAX in the FS_DAX_LIMITED case implemented by the s390/dcssblk driver. Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Michal Hocko Reported-by: kbuild test robot Reported-by: Thomas Meyer Reported-by: Dave Jiang Cc: "Jérôme Glisse" Reviewed-by: Jan Kara Reviewed-by: Christoph Hellwig Signed-off-by: Dan Williams

mm: don't allow deferred pages with NEED_PER_CPU_KM

2018-05-19T00:17:12Z

It is unsafe to do virtual to physical translations before mm_init() is called if struct page is needed in order to determine the memory section number (see SECTION_IN_PAGE_FLAGS). This is because only in mm_init() we initialize struct pages for all the allocated memory when deferred struct pages are used. My recent fix in commit c9e97a1997 ("mm: initialize pages on demand during boot") exposed this problem, because it greatly reduced number of pages that are initialized before mm_init(), but the problem existed even before my fix, as Fengguang Wu found. Below is a more detailed explanation of the problem. We initialize struct pages in four places: 1. Early in boot a small set of struct pages is initialized to fill the first section, and lower zones. 2. During mm_init() we initialize "struct pages" for all the memory that is allocated, i.e reserved in memblock. 3. Using on-demand logic when pages are allocated after mm_init call (when memblock is finished) 4. After smp_init() when the rest free deferred pages are initialized. The problem occurs if we try to do va to phys translation of a memory between steps 1 and 2. Because we have not yet initialized struct pages for all the reserved pages, it is inherently unsafe to do va to phys if the translation itself requires access of "struct page" as in case of this combination: CONFIG_SPARSE && !CONFIG_SPARSE_VMEMMAP The following path exposes the problem: start_kernel() trap_init() setup_cpu_entry_areas() setup_cpu_entry_area(cpu) get_cpu_gdt_paddr(cpu) per_cpu_ptr_to_phys(addr) pcpu_addr_to_page(addr) virt_to_page(addr) pfn_to_page(__pa(addr) >> PAGE_SHIFT) We disable this path by not allowing NEED_PER_CPU_KM with deferred struct pages feature. The problems are discussed in these threads: http://lkml.kernel.org/r/20180418135300.inazvpxjxowogyge@wfg-t540p.sh.intel.com http://lkml.kernel.org/r/20180419013128.iurzouiqxvcnpbvz@wfg-t540p.sh.intel.com http://lkml.kernel.org/r/20180426202619.2768-1-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180515175124.1770-1-pasha.tatashin@oracle.com Fixes: 3a80a7fa7989 ("mm: meminit: initialise a subset of struct pages if CONFIG_DEFERRED_STRUCT_PAGE_INIT is set") Signed-off-by: Pavel Tatashin Acked-by: Michal Hocko Reviewed-by: Andrew Morton Cc: Steven Sistare Cc: Daniel Jordan Cc: Mel Gorman Cc: Fengguang Wu Cc: Dennis Zhou Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

arch: remove the ARCH_PHYS_ADDR_T_64BIT config symbol

2018-05-09T04:56:33Z

Instead select the PHYS_ADDR_T_64BIT for 32-bit architectures that need a 64-bit phys_addr_t type directly. Signed-off-by: Christoph Hellwig Acked-by: James Hogan