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authorJames Morse <james.morse@arm.com>2018-08-30 16:05:32 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-09-09 19:56:02 +0200
commit29245d36680efe1b268bef0072f06bf201847abe (patch)
tree577978311511d716a46d0c830ac56857a955ad56
parent3098933c12130afd50c7474ee3e7318aecce3297 (diff)
arm64: mm: always enable CONFIG_HOLES_IN_ZONE
commit f52bb98f5aded4c43e52f5ce19fb83f7261e9e73 upstream. Commit 6d526ee26ccd ("arm64: mm: enable CONFIG_HOLES_IN_ZONE for NUMA") only enabled HOLES_IN_ZONE for NUMA systems because the NUMA code was choking on the missing zone for nomap pages. This problem doesn't just apply to NUMA systems. If the architecture doesn't set HAVE_ARCH_PFN_VALID, pfn_valid() will return true if the pfn is part of a valid sparsemem section. When working with multiple pages, the mm code uses pfn_valid_within() to test each page it uses within the sparsemem section is valid. On most systems memory comes in MAX_ORDER_NR_PAGES chunks which all have valid/initialised struct pages. In this case pfn_valid_within() is optimised out. Systems where this isn't true (e.g. due to nomap) should set HOLES_IN_ZONE and provide HAVE_ARCH_PFN_VALID so that mm tests each page as it works with it. Currently non-NUMA arm64 systems can't enable HOLES_IN_ZONE, leading to a VM_BUG_ON(): | page:fffffdff802e1780 is uninitialized and poisoned | raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff | raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff | page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) | ------------[ cut here ]------------ | kernel BUG at include/linux/mm.h:978! | Internal error: Oops - BUG: 0 [#1] PREEMPT SMP [...] | CPU: 1 PID: 25236 Comm: dd Not tainted 4.18.0 #7 | Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 | pstate: 40000085 (nZcv daIf -PAN -UAO) | pc : move_freepages_block+0x144/0x248 | lr : move_freepages_block+0x144/0x248 | sp : fffffe0071177680 [...] | Process dd (pid: 25236, stack limit = 0x0000000094cc07fb) | Call trace: | move_freepages_block+0x144/0x248 | steal_suitable_fallback+0x100/0x16c | get_page_from_freelist+0x440/0xb20 | __alloc_pages_nodemask+0xe8/0x838 | new_slab+0xd4/0x418 | ___slab_alloc.constprop.27+0x380/0x4a8 | __slab_alloc.isra.21.constprop.26+0x24/0x34 | kmem_cache_alloc+0xa8/0x180 | alloc_buffer_head+0x1c/0x90 | alloc_page_buffers+0x68/0xb0 | create_empty_buffers+0x20/0x1ec | create_page_buffers+0xb0/0xf0 | __block_write_begin_int+0xc4/0x564 | __block_write_begin+0x10/0x18 | block_write_begin+0x48/0xd0 | blkdev_write_begin+0x28/0x30 | generic_perform_write+0x98/0x16c | __generic_file_write_iter+0x138/0x168 | blkdev_write_iter+0x80/0xf0 | __vfs_write+0xe4/0x10c | vfs_write+0xb4/0x168 | ksys_write+0x44/0x88 | sys_write+0xc/0x14 | el0_svc_naked+0x30/0x34 | Code: aa1303e0 90001a01 91296421 94008902 (d4210000) | ---[ end trace 1601ba47f6e883fe ]--- Remove the NUMA dependency. Link: https://www.spinics.net/lists/arm-kernel/msg671851.html Cc: <stable@vger.kernel.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reported-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com> Tested-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/arm64/Kconfig1
1 files changed, 0 insertions, 1 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1bbb89d37f57..c30cd78b6918 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -693,7 +693,6 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK
config HOLES_IN_ZONE
def_bool y
- depends on NUMA
source kernel/Kconfig.preempt
source kernel/Kconfig.hz