mm/compaction: remove unnecessary cursor page in isolate_freepages_block

The cursor is only used for page forward currently.  We can simply move
page forward directly to remove unnecessary cursor.

Link: https://lkml.kernel.org/r/20230803094901.2915942-4-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kemeng Shi <shikemeng@huawei.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/compaction.c b/mm/compaction.c
index d32929f39dc472f80a09d90c2de601c74604b979..82fd543b410e1e1e7daf2931fbd9286a61147a41 100644 (file)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -589,7 +589,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
                                bool strict)
 {
        int nr_scanned = 0, total_isolated = 0;
-       struct page *cursor;
+       struct page *page;
        unsigned long flags = 0;
        bool locked = false;
        unsigned long blockpfn = *start_pfn;
@@ -599,12 +599,11 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
        if (strict)
                stride = 1;
 
-       cursor = pfn_to_page(blockpfn);
+       page = pfn_to_page(blockpfn);
 
        /* Isolate free pages. */
-       for (; blockpfn < end_pfn; blockpfn += stride, cursor += stride) {
+       for (; blockpfn < end_pfn; blockpfn += stride, page += stride) {
                int isolated;
-               struct page *page = cursor;
 
                /*
                 * Periodically drop the lock (if held) regardless of its
@@ -629,7 +628,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
 
                        if (likely(order <= MAX_ORDER)) {
                                blockpfn += (1UL << order) - 1;
-                               cursor += (1UL << order) - 1;
+                               page += (1UL << order) - 1;
                                nr_scanned += (1UL << order) - 1;
                        }
                        goto isolate_fail;
@@ -666,7 +665,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
                }
                /* Advance to the end of split page */
                blockpfn += isolated - 1;
-               cursor += isolated - 1;
+               page += isolated - 1;
                continue;
 
 isolate_fail: