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From:   Zi Yan <zi.yan@sent.com>
To:     linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc:     Zi Yan <ziy@nvidia.com>, Ryan Roberts <ryan.roberts@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        David Hildenbrand <david@redhat.com>,
        "Yin, Fengwei" <fengwei.yin@intel.com>,
        Yu Zhao <yuzhao@google.com>, Vlastimil Babka <vbabka@suse.cz>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Baolin Wang <baolin.wang@linux.alibaba.com>,
        Kemeng Shi <shikemeng@huaweicloud.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Rohan Puri <rohan.puri15@gmail.com>,
        Mcgrof Chamberlain <mcgrof@kernel.org>,
        Adam Manzanares <a.manzanares@samsung.com>,
        John Hubbard <jhubbard@nvidia.com>
Subject: [RFC PATCH 4/4] mm/compaction: enable compacting >0 order folios.
Date:   Tue, 12 Sep 2023 12:28:15 -0400
Message-Id: <20230912162815.440749-5-zi.yan@sent.com>
In-Reply-To: <20230912162815.440749-1-zi.yan@sent.com>
References: <20230912162815.440749-1-zi.yan@sent.com>
Reply-To: Zi Yan <ziy@nvidia.com>
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From: Zi Yan <ziy@nvidia.com>

Since compaction code can compact >0 order folios, enable it during the
process.

Signed-off-by: Zi Yan <ziy@nvidia.com>
---
 mm/compaction.c | 25 ++++++++++---------------
 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index 4300d877b824..f72af74094de 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1087,11 +1087,17 @@ isolate_migratepages_block(struct compact_control *=
cc, unsigned long low_pfn,
 		if (PageCompound(page) && !cc->alloc_contig) {
 			const unsigned int order =3D compound_order(page);
=20
-			if (likely(order <=3D MAX_ORDER)) {
-				low_pfn +=3D (1UL << order) - 1;
-				nr_scanned +=3D (1UL << order) - 1;
+			/*
+			 * Compacting > pageblock_order pages does not improve
+			 * memory fragmentation. Also skip hugetlbfs pages.
+			 */
+			if (likely(order >=3D pageblock_order) || PageHuge(page)) {
+				if (order <=3D MAX_ORDER) {
+					low_pfn +=3D (1UL << order) - 1;
+					nr_scanned +=3D (1UL << order) - 1;
+				}
+				goto isolate_fail;
 			}
-			goto isolate_fail;
 		}
=20
 		/*
@@ -1214,17 +1220,6 @@ isolate_migratepages_block(struct compact_control *c=
c, unsigned long low_pfn,
 					goto isolate_abort;
 				}
 			}
-
-			/*
-			 * folio become large since the non-locked check,
-			 * and it's on LRU.
-			 */
-			if (unlikely(folio_test_large(folio) && !cc->alloc_contig)) {
-				low_pfn +=3D folio_nr_pages(folio) - 1;
-				nr_scanned +=3D folio_nr_pages(folio) - 1;
-				folio_set_lru(folio);
-				goto isolate_fail_put;
-			}
 		}
=20
 		/* The folio is taken off the LRU */
--=20
2.40.1