linux-kernel - [PATCH 4/8] mm/compaction: remove stale fast_find_block flag in isolate

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Message-Id: <20230728171037.2219226-5-shikemeng@huaweicloud.com>
Date:   Sat, 29 Jul 2023 01:10:33 +0800
From:   Kemeng Shi <shikemeng@...weicloud.com>
To:     akpm@...ux-foundation.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, baolin.wang@...ux.alibaba.com,
        mgorman@...hsingularity.net, willy@...radead.org, david@...hat.com
Cc:     shikemeng@...weicloud.com
Subject: [PATCH 4/8] mm/compaction: remove stale fast_find_block flag in isolate_migratepages

In old code, we set skip to found page block in fast_find_migrateblock. So
we use fast_find_block to avoid skip found page block from
fast_find_migrateblock.
In 90ed667c03fe5 ("Revert "Revert "mm/compaction: fix set skip in
fast_find_migrateblock"""), we remove skip set in fast_find_migrateblock,
then fast_find_block is useless.

Signed-off-by: Kemeng Shi <shikemeng@...weicloud.com>
---
 mm/compaction.c | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index ad535f880c70..09c36251c613 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1949,7 +1949,6 @@ static isolate_migrate_t isolate_migratepages(struct compact_control *cc)
 	const isolate_mode_t isolate_mode =
 		(sysctl_compact_unevictable_allowed ? ISOLATE_UNEVICTABLE : 0) |
 		(cc->mode != MIGRATE_SYNC ? ISOLATE_ASYNC_MIGRATE : 0);
-	bool fast_find_block;
 
 	/*
 	 * Start at where we last stopped, or beginning of the zone as
@@ -1961,13 +1960,6 @@ static isolate_migrate_t isolate_migratepages(struct compact_control *cc)
 	if (block_start_pfn < cc->zone->zone_start_pfn)
 		block_start_pfn = cc->zone->zone_start_pfn;
 
-	/*
-	 * fast_find_migrateblock marks a pageblock skipped so to avoid
-	 * the isolation_suitable check below, check whether the fast
-	 * search was successful.
-	 */
-	fast_find_block = low_pfn != cc->migrate_pfn && !cc->fast_search_fail;
-
 	/* Only scan within a pageblock boundary */
 	block_end_pfn = pageblock_end_pfn(low_pfn);
 
@@ -1976,7 +1968,6 @@ static isolate_migrate_t isolate_migratepages(struct compact_control *cc)
 	 * Do not cross the free scanner.
 	 */
 	for (; block_end_pfn <= cc->free_pfn;
-			fast_find_block = false,
 			cc->migrate_pfn = low_pfn = block_end_pfn,
 			block_start_pfn = block_end_pfn,
 			block_end_pfn += pageblock_nr_pages) {
@@ -2007,8 +1998,7 @@ static isolate_migrate_t isolate_migratepages(struct compact_control *cc)
 		 * before making it "skip" so other compaction instances do
 		 * not scan the same block.
 		 */
-		if (pageblock_aligned(low_pfn) &&
-		    !fast_find_block && !isolation_suitable(cc, page))
+		if (pageblock_aligned(low_pfn) && !isolation_suitable(cc, page))
 			continue;
 
 		/*
-- 
2.30.0