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authorOmar Sandoval <osandov@fb.com>2018-05-09 02:08:53 -0700
committerJens Axboe <axboe@kernel.dk>2018-05-09 08:33:09 -0600
commit522a777566f5669606a1227bf13f3fb40963780b (patch)
tree7d37c9d591e5a9abb4fd1209f1c503ae1a0e8475 /block/blk-merge.c
parent4bc6339a583cec650b05d6fdcc83f03f941c1a3b (diff)
block: consolidate struct request timestamp fields
Currently, struct request has four timestamp fields: - A start time, set at get_request time, in jiffies, used for iostats - An I/O start time, set at start_request time, in ktime nanoseconds, used for blk-stats (i.e., wbt, kyber, hybrid polling) - Another start time and another I/O start time, used for cfq and bfq These can all be consolidated into one start time and one I/O start time, both in ktime nanoseconds, shaving off up to 16 bytes from struct request depending on the kernel config. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-merge.c')
-rw-r--r--block/blk-merge.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 782940c65d8a..5573d0fbec53 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -724,13 +724,12 @@ static struct request *attempt_merge(struct request_queue *q,
}
/*
- * At this point we have either done a back merge
- * or front merge. We need the smaller start_time of
- * the merged requests to be the current request
- * for accounting purposes.
+ * At this point we have either done a back merge or front merge. We
+ * need the smaller start_time_ns of the merged requests to be the
+ * current request for accounting purposes.
*/
- if (time_after(req->start_time, next->start_time))
- req->start_time = next->start_time;
+ if (next->start_time_ns < req->start_time_ns)
+ req->start_time_ns = next->start_time_ns;
req->biotail->bi_next = next->bio;
req->biotail = next->biotail;