[PATCH 0/7] enable PT_RECLAIM on all 64-bit architectures

Qi Zheng
2025-11-14T11:13:45Z

From: Qi Zheng <zhengqi.arch@bytedance.com>

Hi all,

This series aims to enable PT_RECLAIM on all 64-bit architectures.

On a 64-bit system, madvise(MADV_DONTNEED) may cause a large number of empty PTE
page table pages (such as 100GB+). To resolve this problem, we need to enable
PT_RECLAIM, which depends on MMU_GATHER_RCU_TABLE_FREE.

Therefore, this series first enables MMU_GATHER_RCU_TABLE_FREE on all 64-bit
architectures, and finally makes PT_RECLAIM depend on MMU_GATHER_RCU_TABLE_FREE
&& 64BIT. This way, PT_RECLAIM can be enabled by default on all 64-bit
architectures.

Comments and suggestions are welcome!

Thanks,
Qi

Qi Zheng (7):
alpha: mm: enable MMU_GATHER_RCU_TABLE_FREE
arc: mm: enable MMU_GATHER_RCU_TABLE_FREE
loongarch: mm: enable MMU_GATHER_RCU_TABLE_FREE
mips: mm: enable MMU_GATHER_RCU_TABLE_FREE
parisc: mm: enable MMU_GATHER_RCU_TABLE_FREE
um: mm: enable MMU_GATHER_RCU_TABLE_FREE
mm: make PT_RECLAIM depend on MMU_GATHER_RCU_TABLE_FREE && 64BIT

arch/alpha/Kconfig | 1 +
arch/alpha/include/asm/tlb.h | 8 +++++---
arch/arc/Kconfig | 1 +
arch/arc/include/asm/pgalloc.h | 9 ++++++---
arch/loongarch/Kconfig | 1 +
arch/loongarch/include/asm/pgalloc.h | 6 ++++--
arch/mips/Kconfig | 1 +
arch/mips/include/asm/pgalloc.h | 6 ++++--
arch/parisc/Kconfig | 1 +
arch/parisc/include/asm/tlb.h | 6 ++++--
arch/um/Kconfig | 1 +
arch/x86/Kconfig | 1 -
mm/Kconfig | 6 +-----
13 files changed, 30 insertions(+), 18 deletions(-)

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2.20.1