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MFC r276983: When aggregating TRIM segments, move the new one to the end.

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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.
This commit is contained in:
mav 2015-01-25 14:31:44 +00:00
parent 35b0606440
commit e6f27f6344
1 changed files with 6 additions and 0 deletions
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6
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/trim_map.c
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@ -253,17 +253,23 @@ trim_map_segment_add(trim_map_t *tm, uint64_t start, uint64_t end, uint64_t txg)
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);