From: J. Eric Ivancich <ivancich@redhat.com>
Date: Wed, 2 Aug 2017 21:28:11 +0000 (-0400)
Subject: doc: op queue and mclock related options
X-Git-Tag: v12.1.3~62^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=dec1aeeffd43b017f219ac265b627139024e37b5;p=ceph.git

doc: op queue and mclock related options

Additionally makes sure when unexpected values are provided for config
options osd_op_queue or osd_op_queue_cut_off that the default values
are assigned.

Signed-off-by: J. Eric Ivancich <ivancich@redhat.com>
---

diff --git a/src/common/options.cc b/src/common/options.cc
index 85b5a099e300..4ed119465bf9 100644
--- a/src/common/options.cc
+++ b/src/common/options.cc
@@ -1881,71 +1881,317 @@ std::vector<Option> get_global_options() {
 
     Option("osd_op_queue", Option::TYPE_STR, Option::LEVEL_ADVANCED)
     .set_default("wpq")
-    .set_description(""),
+    .set_enum_allowed( { "wpq", "prioritized", "mclock_opclass", "mclock_client", "debug_random" } )
+    .set_description("which operation queue algorithm to use")
+    .set_long_description("which operation queue algorithm to use; mclock_opclass and mclock_client are currently experimental")
+    .add_see_also("osd_op_queue_cut_off"),
 
     Option("osd_op_queue_cut_off", Option::TYPE_STR, Option::LEVEL_ADVANCED)
     .set_default("low")
-    .set_description(""),
+    .set_enum_allowed( { "low", "high", "debug_random" } )
+    .set_description("the threshold between high priority ops and low priority ops")
+    .set_long_description("the threshold between high priority ops that use strict priority ordering and low priority ops that use a fairness algorithm that may or may not incorporate priority")
+    .add_see_also("osd_op_queue"),
 
     Option("osd_op_queue_mclock_client_op_res", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(1000.0)
-    .set_description(""),
+    .set_description("mclock reservation of client operator requests")
+    .set_long_description("mclock reservation of client operator requests when osd_op_queue is either 'mclock_opclass' or 'mclock_client'; higher values increase the reservation")
+    .add_see_also("osd_op_queue")
+    .add_see_also("osd_op_queue_mclock_client_op_wgt")
+    .add_see_also("osd_op_queue_mclock_client_op_lim")
+    .add_see_also("osd_op_queue_mclock_osd_subop_res")
+    .add_see_also("osd_op_queue_mclock_osd_subop_wgt")
+    .add_see_also("osd_op_queue_mclock_osd_subop_lim")
+    .add_see_also("osd_op_queue_mclock_snap_res")
+    .add_see_also("osd_op_queue_mclock_snap_wgt")
+    .add_see_also("osd_op_queue_mclock_snap_lim")
+    .add_see_also("osd_op_queue_mclock_recov_res")
+    .add_see_also("osd_op_queue_mclock_recov_wgt")
+    .add_see_also("osd_op_queue_mclock_recov_lim")
+    .add_see_also("osd_op_queue_mclock_scrub_res")
+    .add_see_also("osd_op_queue_mclock_scrub_wgt")
+    .add_see_also("osd_op_queue_mclock_scrub_lim"),
 
     Option("osd_op_queue_mclock_client_op_wgt", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(500.0)
-    .set_description(""),
+    .set_description("mclock weight of client operator requests")
+    .set_long_description("mclock weight of client operator requests when osd_op_queue is either 'mclock_opclass' or 'mclock_client'; higher values increase the weight")
+    .add_see_also("osd_op_queue")
+    .add_see_also("osd_op_queue_mclock_client_op_res")
+    .add_see_also("osd_op_queue_mclock_client_op_lim")
+    .add_see_also("osd_op_queue_mclock_osd_subop_res")
+    .add_see_also("osd_op_queue_mclock_osd_subop_wgt")
+    .add_see_also("osd_op_queue_mclock_osd_subop_lim")
+    .add_see_also("osd_op_queue_mclock_snap_res")
+    .add_see_also("osd_op_queue_mclock_snap_wgt")
+    .add_see_also("osd_op_queue_mclock_snap_lim")
+    .add_see_also("osd_op_queue_mclock_recov_res")
+    .add_see_also("osd_op_queue_mclock_recov_wgt")
+    .add_see_also("osd_op_queue_mclock_recov_lim")
+    .add_see_also("osd_op_queue_mclock_scrub_res")
+    .add_see_also("osd_op_queue_mclock_scrub_wgt")
+    .add_see_also("osd_op_queue_mclock_scrub_lim"),
 
     Option("osd_op_queue_mclock_client_op_lim", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(0.0)
-    .set_description(""),
+    .set_description("mclock limit of client operator requests")
+    .set_long_description("mclock limit of client operator requests when osd_op_queue is either 'mclock_opclass' or 'mclock_client'; higher values increase the limit")
+    .add_see_also("osd_op_queue")
+    .add_see_also("osd_op_queue_mclock_client_op_res")
+    .add_see_also("osd_op_queue_mclock_client_op_wgt")
+    .add_see_also("osd_op_queue_mclock_osd_subop_res")
+    .add_see_also("osd_op_queue_mclock_osd_subop_wgt")
+    .add_see_also("osd_op_queue_mclock_osd_subop_lim")
+    .add_see_also("osd_op_queue_mclock_snap_res")
+    .add_see_also("osd_op_queue_mclock_snap_wgt")
+    .add_see_also("osd_op_queue_mclock_snap_lim")
+    .add_see_also("osd_op_queue_mclock_recov_res")
+    .add_see_also("osd_op_queue_mclock_recov_wgt")
+    .add_see_also("osd_op_queue_mclock_recov_lim")
+    .add_see_also("osd_op_queue_mclock_scrub_res")
+    .add_see_also("osd_op_queue_mclock_scrub_wgt")
+    .add_see_also("osd_op_queue_mclock_scrub_lim"),
 
     Option("osd_op_queue_mclock_osd_subop_res", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(1000.0)
-    .set_description(""),
+    .set_description("mclock reservation of osd sub-operation requests")
+    .set_long_description("mclock reservation of osd sub-operation requests when osd_op_queue is either 'mclock_opclass' or 'mclock_client'; higher values increase the reservation")
+    .add_see_also("osd_op_queue")
+    .add_see_also("osd_op_queue_mclock_client_op_res")
+    .add_see_also("osd_op_queue_mclock_client_op_wgt")
+    .add_see_also("osd_op_queue_mclock_client_op_lim")
+    .add_see_also("osd_op_queue_mclock_osd_subop_wgt")
+    .add_see_also("osd_op_queue_mclock_osd_subop_lim")
+    .add_see_also("osd_op_queue_mclock_snap_res")
+    .add_see_also("osd_op_queue_mclock_snap_wgt")
+    .add_see_also("osd_op_queue_mclock_snap_lim")
+    .add_see_also("osd_op_queue_mclock_recov_res")
+    .add_see_also("osd_op_queue_mclock_recov_wgt")
+    .add_see_also("osd_op_queue_mclock_recov_lim")
+    .add_see_also("osd_op_queue_mclock_scrub_res")
+    .add_see_also("osd_op_queue_mclock_scrub_wgt")
+    .add_see_also("osd_op_queue_mclock_scrub_lim"),
 
     Option("osd_op_queue_mclock_osd_subop_wgt", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(500.0)
-    .set_description(""),
+    .set_description("mclock weight of osd sub-operation requests")
+    .set_long_description("mclock weight of osd sub-operation requests when osd_op_queue is either 'mclock_opclass' or 'mclock_client'; higher values increase the weight")
+    .add_see_also("osd_op_queue")
+    .add_see_also("osd_op_queue_mclock_client_op_res")
+    .add_see_also("osd_op_queue_mclock_client_op_wgt")
+    .add_see_also("osd_op_queue_mclock_client_op_lim")
+    .add_see_also("osd_op_queue_mclock_osd_subop_res")
+    .add_see_also("osd_op_queue_mclock_osd_subop_lim")
+    .add_see_also("osd_op_queue_mclock_snap_res")
+    .add_see_also("osd_op_queue_mclock_snap_wgt")
+    .add_see_also("osd_op_queue_mclock_snap_lim")
+    .add_see_also("osd_op_queue_mclock_recov_res")
+    .add_see_also("osd_op_queue_mclock_recov_wgt")
+    .add_see_also("osd_op_queue_mclock_recov_lim")
+    .add_see_also("osd_op_queue_mclock_scrub_res")
+    .add_see_also("osd_op_queue_mclock_scrub_wgt")
+    .add_see_also("osd_op_queue_mclock_scrub_lim"),
 
     Option("osd_op_queue_mclock_osd_subop_lim", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(0.0)
-    .set_description(""),
+    .set_description("mclock limit of osd sub-operation requests")
+    .set_long_description("mclock limit of osd sub-operation requests when osd_op_queue is either 'mclock_opclass' or 'mclock_client'; higher values increase the limit")
+    .add_see_also("osd_op_queue")
+    .add_see_also("osd_op_queue_mclock_client_op_res")
+    .add_see_also("osd_op_queue_mclock_client_op_wgt")
+    .add_see_also("osd_op_queue_mclock_client_op_lim")
+    .add_see_also("osd_op_queue_mclock_osd_subop_res")
+    .add_see_also("osd_op_queue_mclock_osd_subop_wgt")
+    .add_see_also("osd_op_queue_mclock_snap_res")
+    .add_see_also("osd_op_queue_mclock_snap_wgt")
+    .add_see_also("osd_op_queue_mclock_snap_lim")
+    .add_see_also("osd_op_queue_mclock_recov_res")
+    .add_see_also("osd_op_queue_mclock_recov_wgt")
+    .add_see_also("osd_op_queue_mclock_recov_lim")
+    .add_see_also("osd_op_queue_mclock_scrub_res")
+    .add_see_also("osd_op_queue_mclock_scrub_wgt")
+    .add_see_also("osd_op_queue_mclock_scrub_lim"),
 
     Option("osd_op_queue_mclock_snap_res", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(0.0)
-    .set_description(""),
+    .set_description("mclock reservation of snaptrim requests")
+    .set_long_description("mclock reservation of snaptrim requests when osd_op_queue is either 'mclock_opclass' or 'mclock_client'; higher values increase the reservation")
+    .add_see_also("osd_op_queue")
+    .add_see_also("osd_op_queue_mclock_client_op_res")
+    .add_see_also("osd_op_queue_mclock_client_op_wgt")
+    .add_see_also("osd_op_queue_mclock_client_op_lim")
+    .add_see_also("osd_op_queue_mclock_osd_subop_res")
+    .add_see_also("osd_op_queue_mclock_osd_subop_wgt")
+    .add_see_also("osd_op_queue_mclock_osd_subop_lim")
+    .add_see_also("osd_op_queue_mclock_snap_wgt")
+    .add_see_also("osd_op_queue_mclock_snap_lim")
+    .add_see_also("osd_op_queue_mclock_recov_res")
+    .add_see_also("osd_op_queue_mclock_recov_wgt")
+    .add_see_also("osd_op_queue_mclock_recov_lim")
+    .add_see_also("osd_op_queue_mclock_scrub_res")
+    .add_see_also("osd_op_queue_mclock_scrub_wgt")
+    .add_see_also("osd_op_queue_mclock_scrub_lim"),
 
     Option("osd_op_queue_mclock_snap_wgt", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(1.0)
-    .set_description(""),
+    .set_description("mclock weight of snaptrim requests")
+    .set_long_description("mclock weight of snaptrim requests when osd_op_queue is either 'mclock_opclass' or 'mclock_client'; higher values increase the weight")
+    .add_see_also("osd_op_queue")
+    .add_see_also("osd_op_queue_mclock_client_op_res")
+    .add_see_also("osd_op_queue_mclock_client_op_wgt")
+    .add_see_also("osd_op_queue_mclock_client_op_lim")
+    .add_see_also("osd_op_queue_mclock_osd_subop_res")
+    .add_see_also("osd_op_queue_mclock_osd_subop_wgt")
+    .add_see_also("osd_op_queue_mclock_osd_subop_lim")
+    .add_see_also("osd_op_queue_mclock_snap_res")
+    .add_see_also("osd_op_queue_mclock_snap_lim")
+    .add_see_also("osd_op_queue_mclock_recov_res")
+    .add_see_also("osd_op_queue_mclock_recov_wgt")
+    .add_see_also("osd_op_queue_mclock_recov_lim")
+    .add_see_also("osd_op_queue_mclock_scrub_res")
+    .add_see_also("osd_op_queue_mclock_scrub_wgt")
+    .add_see_also("osd_op_queue_mclock_scrub_lim"),
 
     Option("osd_op_queue_mclock_snap_lim", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(0.001)
-    .set_description(""),
+    .set_description("")
+    .set_description("mclock limit of snaptrim requests")
+    .set_long_description("mclock limit of snaptrim requests when osd_op_queue is either 'mclock_opclass' or 'mclock_client'; higher values increase the limit")
+    .add_see_also("osd_op_queue_mclock_client_op_res")
+    .add_see_also("osd_op_queue_mclock_client_op_wgt")
+    .add_see_also("osd_op_queue_mclock_client_op_lim")
+    .add_see_also("osd_op_queue_mclock_osd_subop_res")
+    .add_see_also("osd_op_queue_mclock_osd_subop_wgt")
+    .add_see_also("osd_op_queue_mclock_osd_subop_lim")
+    .add_see_also("osd_op_queue_mclock_snap_res")
+    .add_see_also("osd_op_queue_mclock_snap_wgt")
+    .add_see_also("osd_op_queue_mclock_recov_res")
+    .add_see_also("osd_op_queue_mclock_recov_wgt")
+    .add_see_also("osd_op_queue_mclock_recov_lim")
+    .add_see_also("osd_op_queue_mclock_scrub_res")
+    .add_see_also("osd_op_queue_mclock_scrub_wgt")
+    .add_see_also("osd_op_queue_mclock_scrub_lim"),
 
     Option("osd_op_queue_mclock_recov_res", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(0.0)
-    .set_description(""),
+    .set_description("mclock reservation of recovery requests")
+    .set_long_description("mclock reservation of recovery requests when osd_op_queue is either 'mclock_opclass' or 'mclock_client'; higher values increase the reservation")
+    .add_see_also("osd_op_queue")
+    .add_see_also("osd_op_queue_mclock_client_op_res")
+    .add_see_also("osd_op_queue_mclock_client_op_wgt")
+    .add_see_also("osd_op_queue_mclock_client_op_lim")
+    .add_see_also("osd_op_queue_mclock_osd_subop_res")
+    .add_see_also("osd_op_queue_mclock_osd_subop_wgt")
+    .add_see_also("osd_op_queue_mclock_osd_subop_lim")
+    .add_see_also("osd_op_queue_mclock_snap_res")
+    .add_see_also("osd_op_queue_mclock_snap_wgt")
+    .add_see_also("osd_op_queue_mclock_snap_lim")
+    .add_see_also("osd_op_queue_mclock_recov_wgt")
+    .add_see_also("osd_op_queue_mclock_recov_lim")
+    .add_see_also("osd_op_queue_mclock_scrub_res")
+    .add_see_also("osd_op_queue_mclock_scrub_wgt")
+    .add_see_also("osd_op_queue_mclock_scrub_lim"),
 
     Option("osd_op_queue_mclock_recov_wgt", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(1.0)
-    .set_description(""),
+    .set_description("mclock weight of recovery requests")
+    .set_long_description("mclock weight of recovery requests when osd_op_queue is either 'mclock_opclass' or 'mclock_client'; higher values increase the weight")
+    .add_see_also("osd_op_queue")
+    .add_see_also("osd_op_queue_mclock_client_op_res")
+    .add_see_also("osd_op_queue_mclock_client_op_wgt")
+    .add_see_also("osd_op_queue_mclock_client_op_lim")
+    .add_see_also("osd_op_queue_mclock_osd_subop_res")
+    .add_see_also("osd_op_queue_mclock_osd_subop_wgt")
+    .add_see_also("osd_op_queue_mclock_osd_subop_lim")
+    .add_see_also("osd_op_queue_mclock_snap_res")
+    .add_see_also("osd_op_queue_mclock_snap_wgt")
+    .add_see_also("osd_op_queue_mclock_snap_lim")
+    .add_see_also("osd_op_queue_mclock_recov_res")
+    .add_see_also("osd_op_queue_mclock_recov_lim")
+    .add_see_also("osd_op_queue_mclock_scrub_res")
+    .add_see_also("osd_op_queue_mclock_scrub_wgt")
+    .add_see_also("osd_op_queue_mclock_scrub_lim"),
 
     Option("osd_op_queue_mclock_recov_lim", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(0.001)
-    .set_description(""),
+    .set_description("mclock limit of recovery requests")
+    .set_long_description("mclock limit of recovery requests when osd_op_queue is either 'mclock_opclass' or 'mclock_client'; higher values increase the limit")
+    .add_see_also("osd_op_queue")
+    .add_see_also("osd_op_queue_mclock_client_op_res")
+    .add_see_also("osd_op_queue_mclock_client_op_wgt")
+    .add_see_also("osd_op_queue_mclock_client_op_lim")
+    .add_see_also("osd_op_queue_mclock_osd_subop_res")
+    .add_see_also("osd_op_queue_mclock_osd_subop_wgt")
+    .add_see_also("osd_op_queue_mclock_osd_subop_lim")
+    .add_see_also("osd_op_queue_mclock_snap_res")
+    .add_see_also("osd_op_queue_mclock_snap_wgt")
+    .add_see_also("osd_op_queue_mclock_snap_lim")
+    .add_see_also("osd_op_queue_mclock_recov_res")
+    .add_see_also("osd_op_queue_mclock_recov_wgt")
+    .add_see_also("osd_op_queue_mclock_scrub_res")
+    .add_see_also("osd_op_queue_mclock_scrub_wgt")
+    .add_see_also("osd_op_queue_mclock_scrub_lim"),
 
     Option("osd_op_queue_mclock_scrub_res", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(0.0)
-    .set_description(""),
+    .set_description("mclock reservation of scrub requests")
+    .set_long_description("mclock reservation of scrub requests when osd_op_queue is either 'mclock_opclass' or 'mclock_client'; higher values increase the reservation")
+    .add_see_also("osd_op_queue")
+    .add_see_also("osd_op_queue_mclock_client_op_res")
+    .add_see_also("osd_op_queue_mclock_client_op_wgt")
+    .add_see_also("osd_op_queue_mclock_client_op_lim")
+    .add_see_also("osd_op_queue_mclock_osd_subop_res")
+    .add_see_also("osd_op_queue_mclock_osd_subop_wgt")
+    .add_see_also("osd_op_queue_mclock_osd_subop_lim")
+    .add_see_also("osd_op_queue_mclock_snap_res")
+    .add_see_also("osd_op_queue_mclock_snap_wgt")
+    .add_see_also("osd_op_queue_mclock_snap_lim")
+    .add_see_also("osd_op_queue_mclock_recov_res")
+    .add_see_also("osd_op_queue_mclock_recov_wgt")
+    .add_see_also("osd_op_queue_mclock_recov_lim")
+    .add_see_also("osd_op_queue_mclock_scrub_wgt")
+    .add_see_also("osd_op_queue_mclock_scrub_lim"),
 
     Option("osd_op_queue_mclock_scrub_wgt", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(1.0)
-    .set_description(""),
+    .set_description("mclock weight of scrub requests")
+    .set_long_description("mclock weight of scrub requests when osd_op_queue is either 'mclock_opclass' or 'mclock_client'; higher values increase the weight")
+    .add_see_also("osd_op_queue")
+    .add_see_also("osd_op_queue_mclock_client_op_res")
+    .add_see_also("osd_op_queue_mclock_client_op_wgt")
+    .add_see_also("osd_op_queue_mclock_client_op_lim")
+    .add_see_also("osd_op_queue_mclock_osd_subop_res")
+    .add_see_also("osd_op_queue_mclock_osd_subop_wgt")
+    .add_see_also("osd_op_queue_mclock_osd_subop_lim")
+    .add_see_also("osd_op_queue_mclock_snap_res")
+    .add_see_also("osd_op_queue_mclock_snap_wgt")
+    .add_see_also("osd_op_queue_mclock_snap_lim")
+    .add_see_also("osd_op_queue_mclock_recov_res")
+    .add_see_also("osd_op_queue_mclock_recov_wgt")
+    .add_see_also("osd_op_queue_mclock_recov_lim")
+    .add_see_also("osd_op_queue_mclock_scrub_res")
+    .add_see_also("osd_op_queue_mclock_scrub_lim"),
 
     Option("osd_op_queue_mclock_scrub_lim", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(0.001)
-    .set_description(""),
+    .set_description("mclock weight of limit requests")
+    .set_long_description("mclock weight of limit requests when osd_op_queue is either 'mclock_opclass' or 'mclock_client'; higher values increase the limit")
+    .add_see_also("osd_op_queue")
+    .add_see_also("osd_op_queue_mclock_client_op_res")
+    .add_see_also("osd_op_queue_mclock_client_op_wgt")
+    .add_see_also("osd_op_queue_mclock_client_op_lim")
+    .add_see_also("osd_op_queue_mclock_osd_subop_res")
+    .add_see_also("osd_op_queue_mclock_osd_subop_wgt")
+    .add_see_also("osd_op_queue_mclock_osd_subop_lim")
+    .add_see_also("osd_op_queue_mclock_snap_res")
+    .add_see_also("osd_op_queue_mclock_snap_wgt")
+    .add_see_also("osd_op_queue_mclock_snap_lim")
+    .add_see_also("osd_op_queue_mclock_recov_res")
+    .add_see_also("osd_op_queue_mclock_recov_wgt")
+    .add_see_also("osd_op_queue_mclock_recov_lim")
+    .add_see_also("osd_op_queue_mclock_scrub_res")
+    .add_see_also("osd_op_queue_mclock_scrub_wgt"),
 
     Option("osd_ignore_stale_divergent_priors", Option::TYPE_BOOL, Option::LEVEL_ADVANCED)
     .set_default(false)
diff --git a/src/osd/OSD.h b/src/osd/OSD.h
index 33e5e3b27ac7..092cbb999052 100644
--- a/src/osd/OSD.h
+++ b/src/osd/OSD.h
@@ -2335,14 +2335,15 @@ private:
       srand(time(NULL));
       unsigned which = rand() % (sizeof(index_lookup) / sizeof(index_lookup[0]));
       return index_lookup[which];
-    } else if (cct->_conf->osd_op_queue == "wpq") {
-      return io_queue::weightedpriority;
+    } else if (cct->_conf->osd_op_queue == "prioritized") {
+      return io_queue::prioritized;
     } else if (cct->_conf->osd_op_queue == "mclock_opclass") {
       return io_queue::mclock_opclass;
     } else if (cct->_conf->osd_op_queue == "mclock_client") {
       return io_queue::mclock_client;
     } else {
-      return io_queue::prioritized;
+      // default / catch-all is 'wpq'
+      return io_queue::weightedpriority;
     }
   }
 
@@ -2350,10 +2351,11 @@ private:
     if (cct->_conf->osd_op_queue_cut_off == "debug_random") {
       srand(time(NULL));
       return (rand() % 2 < 1) ? CEPH_MSG_PRIO_HIGH : CEPH_MSG_PRIO_LOW;
-    } else if (cct->_conf->osd_op_queue_cut_off == "low") {
-      return CEPH_MSG_PRIO_LOW;
-    } else {
+    } else if (cct->_conf->osd_op_queue_cut_off == "high") {
       return CEPH_MSG_PRIO_HIGH;
+    } else {
+      // default / catch-all is 'low'
+      return CEPH_MSG_PRIO_LOW;
     }
   }