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authorJames Morse <james.morse@arm.com>2018-08-30 16:05:32 +0100
committerWill Deacon <will.deacon@arm.com>2018-08-31 11:06:45 +0100
commitf52bb98f5aded4c43e52f5ce19fb83f7261e9e73 (patch)
tree7d0865e583c440b0daaf372ed965f21a033a232e
parent755a8bf5579d22eb5636685c516d8dede799e27b (diff)
arm64: mm: always enable CONFIG_HOLES_IN_ZONE
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>
-rw-r--r--arch/arm64/Kconfig1
1 files changed, 0 insertions, 1 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 29e75b47becd..1b1a0e95c751 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -763,7 +763,6 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK
config HOLES_IN_ZONE
def_bool y
- depends on NUMA
source kernel/Kconfig.hz