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

David Hildenbrand (Red Hat)
2025-11-17T16:53:49Z

On 14.11.25 12:11, Qi Zheng wrote:
> 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.
>

Makes sense!

> 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.

Could we then even go ahead and stop making PT_RECLAIM user-selectable?

--
Cheers

David