Author: mav
Date: Sun Jan 11 16:36:39 2015
New Revision: 276983
URL: https://svnweb.freebsd.org/changeset/base/276983
Log:
When aggregating TRIM segments, move the new one to the list end.
New segment at the list head may block all TRIM requests until txg of that
segment can be processed. On my random I/O tests this change reduce peak
TRIM list length from 650 to 450 segments. Hopefully it should reduce TRIM
burstiness when list processing is unblocked.
MFC after: 2 weeks
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/trim_map.c
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/trim_map.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/trim_map.c Sun Jan
11 16:15:31 2015 (r276982)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/trim_map.c Sun Jan
11 16:36:39 2015 (r276983)
@@ -244,17 +244,23 @@ trim_map_segment_add(trim_map_t *tm, uin
ts_after->ts_start = ts_before->ts_start;
ts_after->ts_txg = txg;
ts_after->ts_time = time;
+ list_remove(&tm->tm_head, ts_after);
+ list_insert_tail(&tm->tm_head, ts_after);
kmem_free(ts_before, sizeof (*ts_before));
} else if (merge_before) {
TRIM_MAP_SINC(tm, end - ts_before->ts_end);
ts_before->ts_end = end;
ts_before->ts_txg = txg;
ts_before->ts_time = time;
+ list_remove(&tm->tm_head, ts_before);
+ list_insert_tail(&tm->tm_head, ts_before);
} else if (merge_after) {
TRIM_MAP_SINC(tm, ts_after->ts_start - start);
ts_after->ts_start = start;
ts_after->ts_txg = txg;
ts_after->ts_time = time;
+ list_remove(&tm->tm_head, ts_after);
+ list_insert_tail(&tm->tm_head, ts_after);
} else {
TRIM_MAP_SINC(tm, end - start);
TRIM_MAP_QINC(tm);
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