libceph: support crush tunables

The server side recently added support for tuning some magic
crush variables. Decode these variables if they are present, or use the
default values if they are not present.

Corresponds to ceph.git commit 89af369c25f274fe62ef730e5e8aad0c54f1e5a5.

Signed-off-by: caleb miles <caleb.miles@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>

2 files changed, 12 insertions, 1 deletions

diff --git a/include/linux/ceph/ceph_features.h b/include/linux/ceph/ceph_features.h
index 342f93dbe162..dad579b0c0e6 100644
--- a/include/linux/ceph/ceph_features.h
+++ b/include/linux/ceph/ceph_features.h
@@ -12,12 +12,15 @@
 #define CEPH_FEATURE_MONNAMES       (1<<5)
 #define CEPH_FEATURE_RECONNECT_SEQ  (1<<6)
 #define CEPH_FEATURE_DIRLAYOUTHASH  (1<<7)
+/* bits 8-17 defined by user-space; not supported yet here */
+#define CEPH_FEATURE_CRUSH_TUNABLES (1<<18)
 
 /*
  * Features supported.
  */
 #define CEPH_FEATURES_SUPPORTED_DEFAULT  \
-        (CEPH_FEATURE_NOSRCADDR)
+        (CEPH_FEATURE_NOSRCADDR |        \
+         CEPH_FEATURE_CRUSH_TUNABLES)
 
 #define CEPH_FEATURES_REQUIRED_DEFAULT   \
         (CEPH_FEATURE_NOSRCADDR)
diff --git a/include/linux/crush/crush.h b/include/linux/crush/crush.h
index 7c4750811b96..25baa287cff7 100644
--- a/include/linux/crush/crush.h
+++ b/include/linux/crush/crush.h
@@ -154,6 +154,14 @@ struct crush_map {
         __s32 max_buckets;
         __u32 max_rules;
         __s32 max_devices;
+
+        /* choose local retries before re-descent */
+        __u32 choose_local_tries;
+        /* choose local attempts using a fallback permutation before
+         * re-descent */
+        __u32 choose_local_fallback_tries;
+        /* choose attempts before giving up */ 
+        __u32 choose_total_tries;
 };