os/bluestore: add bluestore fragmentation micros to prometheus

High fragmentation is one of the factors affecting performance decrease,
add it to prometheus, it helps to us monitor fragmentation changes.

Signed-off-by: Yite Gu <yitegu0@gmail.com>

diff --git a/src/os/bluestore/BlueStore.cc b/src/os/bluestore/BlueStore.cc
index ec03fcde14aeaf9af535acc23a29eb8e0bfac3ee..67f9fb92c6fb28945803d8c5e3b7ecab1f554ba5 100644 (file)
--- a/src/os/bluestore/BlueStore.cc
+++ b/src/os/bluestore/BlueStore.cc
@@ -6088,7 +6088,9 @@ void BlueStore::_init_logger()
            PerfCountersBuilder::PRIO_CRITICAL,
            unit_t(UNIT_BYTES));
   b.add_u64(l_bluestore_fragmentation, "fragmentation_micros",
-            "How fragmented bluestore free space is (free extents / max possible number of free extents) * 1000");
+            "How fragmented bluestore free space is (free extents / max possible number of free extents) * 1000",
+           "fbss",
+           PerfCountersBuilder::PRIO_USEFUL);
   b.add_u64(l_bluestore_alloc_unit, "alloc_unit",
            "allocation unit size in bytes",
            "au_b",