crimson/osd/shard_services: add comment to next_tid initialization

Signed-off-by: Matan Breizman <mbreizma@redhat.com>

diff --git a/src/crimson/osd/shard_services.cc b/src/crimson/osd/shard_services.cc
index 404f28d7d7f3b4ccd5515b6cc2146ff1893b01d9..c0688f9576996820ed9330c4053addc0ba2878ec 100644 (file)
--- a/src/crimson/osd/shard_services.cc
+++ b/src/crimson/osd/shard_services.cc
@@ -47,6 +47,8 @@ PerShardState::PerShardState(
     perf(perf), recoverystate_perf(recoverystate_perf),
     throttler(crimson::common::local_conf()),
     next_tid(
+      // Use shard_id to initialize upper 8 bits of counters to ensure that
+      // ids generated by different shards are disjoint
       static_cast<ceph_tid_t>(seastar::this_shard_id()) <<
       (std::numeric_limits<ceph_tid_t>::digits - 8)),
     startup_time(startup_time)