On Fri, 16 Aug 2024 12:06:25 +0800 Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> wrote:
> The gigantic page size may larger than memory block size, so memory
> offline always fails in this case after commit b2c9e2fbba32 ("mm: make
> alloc_contig_range work at pageblock granularity"),
>
> offline_pages
> start_isolate_page_range
> start_isolate_page_range(isolate_before=true)
> isolate [isolate_start, isolate_start + pageblock_nr_pages)
> start_isolate_page_range(isolate_before=false)
> isolate [isolate_end - pageblock_nr_pages, isolate_end) pageblock
> __alloc_contig_migrate_range
> isolate_migratepages_range
> isolate_migratepages_block
> isolate_or_dissolve_huge_page
> if (hstate_is_gigantic(h))
> return -ENOMEM;
>
> In fact, we don't need to migrate page in page range isolation, for
> memory offline path, there is do_migrate_range() to move the pages.
> For contig allocation, there is another __alloc_contig_migrate_range()
> after isolation to migrate the pages. So fix issue by skipping the
> __alloc_contig_migrate_range() in isolate_single_pageblock().
>
> Fixes: b2c9e2fbba32 ("mm: make alloc_contig_range work at pageblock granularity")
Should we backport this into -stable kernels?
