Subject: + swap-delete-the-last_in_cluster-scan_base-loop-in-the-body-of-scan_swap_map.patch added to -mm tree
To: slaoub@xxxxxxxxx,hughd@xxxxxxxxxx,shli@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Mon, 02 Jun 2014 13:50:08 -0700
The patch titled
Subject: mm/swapfile.c: delete the "last_in_cluster < scan_base" loop in the body of scan_swap_map()
has been added to the -mm tree. Its filename is
swap-delete-the-last_in_cluster-scan_base-loop-in-the-body-of-scan_swap_map.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/swap-delete-the-last_in_cluster-scan_base-loop-in-the-body-of-scan_swap_map.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/swap-delete-the-last_in_cluster-scan_base-loop-in-the-body-of-scan_swap_map.patch
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------------------------------------------------------
From: Chen Yucong <slaoub@xxxxxxxxx>
Subject: mm/swapfile.c: delete the "last_in_cluster < scan_base" loop in the body of scan_swap_map()
Via ebc2a1a69111 ("swap: make cluster allocation per-cpu"), 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@xxxxxxxxx>
Cc: Shaohua Li <shli@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swapfile.c | 20 --------------------
1 file changed, 20 deletions(-)
diff -puN mm/swapfile.c~swap-delete-the-last_in_cluster-scan_base-loop-in-the-body-of-scan_swap_map mm/swapfile.c
--- a/mm/swapfile.c~swap-delete-the-last_in_cluster-scan_base-loop-in-the-body-of-scan_swap_map
+++ a/mm/swapfile.c
@@ -549,26 +549,6 @@ static unsigned long scan_swap_map(struc
}
}
- 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;
_
Patches currently in -mm which might be from slaoub@xxxxxxxxx are
hwpoison-remove-unused-global-variable-in-do_machine_check.patch
swap-delete-the-last_in_cluster-scan_base-loop-in-the-body-of-scan_swap_map.patch
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