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Date:   Thu, 19 May 2022 16:57:55 -0400
From:   Qian Cai <quic_qiancai@quicinc.com>
To:     Zi Yan <ziy@nvidia.com>
CC:     David Hildenbrand <david@redhat.com>, <linux-mm@kvack.org>,
        <linux-kernel@vger.kernel.org>,
        <virtualization@lists.linux-foundation.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Mel Gorman <mgorman@techsingularity.net>,
        Eric Ren <renzhengeek@gmail.com>,
        Mike Rapoport <rppt@kernel.org>,
        "Oscar Salvador" <osalvador@suse.de>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v11 0/6] Use pageblock_order for cma and
 alloc_contig_range alignment.
Message-ID: <YoavU/+NfQIzQiDF@qian>
References: <20220425143118.2850746-1-zi.yan@sent.com>
 <20220426201855.GA1014@qian>
 <B621B4DD-5D11-4F0E-AFF5-F8684AE37E57@nvidia.com>
 <20220426210801.GA1038@qian>
 <2B9844C8-6D35-41E2-ACB2-9854E7A9C29F@nvidia.com>
 <20220427132720.GC71@qian>
 <1D88AE1B-4DFC-400F-A054-662E3824C9AF@nvidia.com>
 <A1956578-A851-4BF3-BD57-12571244DB5E@nvidia.com>
 <20220428123308.GA71@qian>
 <0E75B247-8150-48A3-83AE-56C586030006@nvidia.com>
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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