Re: [PATCH v11 0/6] Use pageblock_order for cma and alloc_contig_range alignment.

[Qian Cai]

On Thu, Apr 28, 2022 at 08:39:06AM -0400, Zi Yan wrote:
> How about the one attached? I can apply it to next-20220428. Let me know
> if you are using a different branch. Thanks.

Zi, it turns out that the endless loop in isolate_single_pageblock() can
still be reproduced on today's linux-next tree by running the reproducer a
few times. With this debug patch applied, it keeps printing the same
values.

--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -399,6 +399,8 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, gfp_t gfp_flags,
                                };
                                INIT_LIST_HEAD(&cc.migratepages);

+                               printk_ratelimited("KK stucked pfn=%lu head_pfn=%lu nr_pages=%lu boundary_pfn=%lu\n", pfn, head_pfn, nr_pages, boundary_pfn);
                                ret = __alloc_contig_migrate_range(&cc, head_pfn,
                                                        head_pfn + nr_pages);

 isolate_single_pageblock: 179 callbacks suppressed
 KK stucked pfn=2151120384 head_pfn=2151120384 nr_pages=512 boundary_pfn=2151120896
 KK stucked pfn=2151120384 head_pfn=2151120384 nr_pages=512 boundary_pfn=2151120896
 KK stucked pfn=2151120384 head_pfn=2151120384 nr_pages=512 boundary_pfn=2151120896
 KK stucked pfn=2151120384 head_pfn=2151120384 nr_pages=512 boundary_pfn=2151120896
 KK stucked pfn=2151120384 head_pfn=2151120384 nr_pages=512 boundary_pfn=2151120896
 KK stucked pfn=2151120384 head_pfn=2151120384 nr_pages=512 boundary_pfn=2151120896
 KK stucked pfn=2151120384 head_pfn=2151120384 nr_pages=512 boundary_pfn=2151120896
 KK stucked pfn=2151120384 head_pfn=2151120384 nr_pages=512 boundary_pfn=2151120896
 KK stucked pfn=2151120384 head_pfn=2151120384 nr_pages=512 boundary_pfn=2151120896
 KK stucked pfn=2151120384 head_pfn=2151120384 nr_pages=512 boundary_pfn=2151120896