Re: [PATCH 0/8] Introduce a huge-page pre-zeroing mechanism

[Andrew Morton]

On Thu, 25 Dec 2025 16:20:51 +0800 李喆 <lizhe.67@xxxxxxxxxxxxx> wrote:

> This patchset is based on this commit[1]("mm/hugetlb: optionally
> pre-zero hugetlb pages").
> 
> Fresh hugetlb pages are zeroed out when they are faulted in,
> just like with all other page types. This can take up a good
> amount of time for larger page sizes (e.g. around 40
> milliseconds for a 1G page on a recent AMD-based system).
> 
> This normally isn't a problem, since hugetlb pages are typically
> mapped by the application for a long time, and the initial
> delay when touching them isn't much of an issue.
> 
> However, there are some use cases where a large number of hugetlb
> pages are touched when an application (such as a VM backed by these
> pages) starts. For 256 1G pages and 40ms per page, this would take
> 10 seconds, a noticeable delay.

Ankur's contiguous page clearing work
(https://lkml.kernel.org/r/20251215204922.475324-1-ankur.a.arora@xxxxxxxxxx)
will hopefully result in significant changes to the timing observations
in your changelogs?