From: Anshuman Khandual anshuman.khandual@arm.com
mainline inclusion from mainline-v5.12-rc3 commit 79cc2ed5a716544621b11a3f90550e5c7d314306 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I611C3 CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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Currently without THP being enabled, MAX_ORDER via FORCE_MAX_ZONEORDER gets reduced to 11, which falls below HUGETLB_PAGE_ORDER for certain 16K and 64K page size configurations. This is problematic which throws up the following warning during boot as pageblock_order via HUGETLB_PAGE_ORDER order exceeds MAX_ORDER.
WARNING: CPU: 7 PID: 127 at mm/vmstat.c:1092 __fragmentation_index+0x58/0x70 Modules linked in: CPU: 7 PID: 127 Comm: kswapd0 Not tainted 5.12.0-rc1-00005-g0221e3101a1 #237 Hardware name: linux,dummy-virt (DT) pstate: 20400005 (nzCv daif +PAN -UAO -TCO BTYPE=--) pc : __fragmentation_index+0x58/0x70 lr : fragmentation_index+0x88/0xa8 sp : ffff800016ccfc00 x29: ffff800016ccfc00 x28: 0000000000000000 x27: ffff800011fd4000 x26: 0000000000000002 x25: ffff800016ccfda0 x24: 0000000000000002 x23: 0000000000000640 x22: ffff0005ffcb5b18 x21: 0000000000000002 x20: 000000000000000d x19: ffff0005ffcb3980 x18: 0000000000000004 x17: 0000000000000001 x16: 0000000000000019 x15: ffff800011ca7fb8 x14: 00000000000002b3 x13: 0000000000000000 x12: 00000000000005e0 x11: 0000000000000003 x10: 0000000000000080 x9 : ffff800011c93948 x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000007000 x5 : 0000000000007944 x4 : 0000000000000032 x3 : 000000000000001c x2 : 000000000000000b x1 : ffff800016ccfc10 x0 : 000000000000000d Call trace: __fragmentation_index+0x58/0x70 compaction_suitable+0x58/0x78 wakeup_kcompactd+0x8c/0xd8 balance_pgdat+0x570/0x5d0 kswapd+0x1e0/0x388 kthread+0x154/0x158 ret_from_fork+0x10/0x30
This solves the problem via keeping FORCE_MAX_ZONEORDER unchanged with or without THP on 16K and 64K page size configurations, making sure that the HUGETLB_PAGE_ORDER (and pageblock_order) would never exceed MAX_ORDER.
Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will@kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com Acked-by: Catalin Marinas catalin.marinas@arm.com Link: https://lore.kernel.org/r/1614597914-28565-1-git-send-email-anshuman.khandua... Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Zhang Peng zhangpeng362@huawei.com Reviewed-by: Chen Wandun chenwandun@huawei.com Reviewed-by: Nanyong Sun sunnanyong@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- arch/arm64/Kconfig | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 6d288cfa313f..ddbdbc7ecdd9 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1287,8 +1287,8 @@ config XEN
config FORCE_MAX_ZONEORDER int - default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE) - default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE) + default "14" if ARM64_64K_PAGES + default "12" if ARM64_16K_PAGES default "11" help The kernel memory allocator divides physically contiguous memory