Re: [PATCH] alloc_tag: Handle incomplete bulk allocations in vm_module_tags_populate

[Andrew Morton]

On Wed,  9 Apr 2025 19:54:47 +0000 "T.J. Mercier" <tjmercier@xxxxxxxxxx> wrote:

> alloc_pages_bulk_node may partially succeed and allocate fewer than the
> requested nr_pages. There are several conditions under which this can
> occur, but we have encountered the case where CONFIG_PAGE_OWNER is
> enabled causing all bulk allocations to always fallback to single page
> allocations due to commit 187ad460b841 ("mm/page_alloc: avoid page
> allocator recursion with pagesets.lock held").
> 
> Currently vm_module_tags_populate immediately fails when
> alloc_pages_bulk_node returns fewer than the requested number of pages.
> This patch causes vm_module_tags_populate to retry bulk allocations for
> the remaining memory instead.

Please describe the userspace-visible runtime effects of this change.  In a way
which permits a user who is experiencing some problem can recognize that this
patch will address that problem.