Re: [RFC PATCH v6 2/5] mm: migrate: Add migrate_misplaced_folios_batch()

Gregory Price
2026-04-22T03:37:51Z

On Wed, Apr 22, 2026 at 08:56:59AM +0530, Bharata B Rao wrote:
> On 21-Apr-26 9:35 PM, Gregory Price wrote:
> > On Tue, Apr 21, 2026 at 08:55:02PM +0530, Donet Tom wrote:
> >>> +/**
> >>> + * migrate_misplaced_folios_batch() - Batch variant of migrate_misplaced_folio
> >>> + * Attempts to migrate a folio list to the specified destination.
> >>> + * @folio_list: Isolated list of folios to be batch-migrated.
> >>> + * @node: The NUMA node ID to where the folios should be migrated.
> >>> + *
> >>> + * Caller is expected to have isolated the folios by calling
> >>> + * migrate_misplaced_folio_prepare(), which will result in an
> >>> + * elevated reference count on the folio. All the isolated folios
> >>> + * in the list must belong to the same memcg so that NUMA_PAGE_MIGRATE
> >>> + * stat can be attributed correctly to the memcg.
>
> ^ This is the expectation from the caller. pghot caller ensures this.
> I could add a debug check in this routine to verify if that is indeed so.
>

Wondering if the interface name should somehow reflect this as well, to
make it a bit clearer.

~Gregory