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Subject[PATCH] swap: Delete the "last_in_cluster < scan_base" loop in the body of scan_swap_map()
Date
From commit ebc2a1a69111, we can find that all SWP_SOLIDSTATE "seek is cheap"(SSD case) 
has already gone to si->cluster_info scan_swap_map_try_ssd_cluster() route. So that the
"last_in_cluster < scan_base" loop in the body of scan_swap_map() has already become a
dead code snippet, and it should have been deleted.

This patch is to delete the redundant loop as Hugh and Shaohua suggested.

Signed-off-by: Chen Yucong <slaoub@gmail.com>
---
mm/swapfile.c | 20 --------------------
1 file changed, 20 deletions(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index beeeef8..1b44bd9 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -549,26 +549,6 @@ static unsigned long scan_swap_map(struct swap_info_struct *si,
}
}

- offset = si->lowest_bit;
- last_in_cluster = offset + SWAPFILE_CLUSTER - 1;
-
- /* Locate the first empty (unaligned) cluster */
- for (; last_in_cluster < scan_base; offset++) {
- if (si->swap_map[offset])
- last_in_cluster = offset + SWAPFILE_CLUSTER;
- else if (offset == last_in_cluster) {
- spin_lock(&si->lock);
- offset -= SWAPFILE_CLUSTER - 1;
- si->cluster_next = offset;
- si->cluster_nr = SWAPFILE_CLUSTER - 1;
- goto checks;
- }
- if (unlikely(--latency_ration < 0)) {
- cond_resched();
- latency_ration = LATENCY_LIMIT;
- }
- }
-
offset = scan_base;
spin_lock(&si->lock);
si->cluster_nr = SWAPFILE_CLUSTER - 1;
--
1.7.10.4


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