crush: apply chooseleaf_tries to firstn mode too

Parameterize the attempts for the _firstn choose method, and apply the
rule-specified tries count to firstn mode as well.  Note that we have
slightly different behavior here than with indep:

 If the firstn value is not specified for firstn, we pass through the
 normal attempt count.  This maintains compatibility with legacy behavior.
 Note that this is usually *not* actually N^2 work, though, because of the
 descend_once tunable.  However, descend_once is unfortunately *not* the
 same thing as 1 chooseleaf try because it is only checked on a reject but
 not on a collision.  Sigh.

 In contrast, for indep, if tries is not specified we default to 1
 recursive attempt, because that is simply more sane, and we have the
 option to do so.  The descend_once tunable has no effect for indep.

Reflects ceph.git commit 64aeded50d80942d66a5ec7b604ff2fcbf5d7b63.

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/net/ceph/crush/mapper.c b/net/ceph/crush/mapper.c
index e3ade074541c..c34320518c8b 100644
--- a/net/ceph/crush/mapper.c
+++ b/net/ceph/crush/mapper.c
@@ -299,6 +299,8 @@ static int crush_choose_firstn(const struct crush_map *map,
                                const __u32 *weight, int weight_max,
                                int x, int numrep, int type,
                                int *out, int outpos,
+                               unsigned int attempts,
+                               unsigned int recurse_attempts,
                                int recurse_to_leaf,
                                int descend_once, int *out2)
 {
@@ -385,6 +387,7 @@ static int crush_choose_firstn(const struct crush_map *map,
                                                          weight, weight_max,
                                                          x, outpos+1, 0,
                                                          out2, outpos,
+                                                         recurse_attempts, 0,
                                                          0,
                                                          map->chooseleaf_descend_once,
                                                          NULL) <= outpos)
@@ -421,7 +424,7 @@ reject:
                                                  flocal <= in->size + map->choose_local_fallback_tries)
                                                 /* exhaustive bucket search */
                                                 retry_bucket = 1;
-                                        else if (ftotal <= map->choose_total_tries)
+                                        else if (ftotal <= attempts)
                                                 /* then retry descent */
                                                 retry_descent = 1;
                                         else
@@ -634,7 +637,8 @@ int crush_do_rule(const struct crush_map *map,
         __u32 step;
         int i, j;
         int numrep;
-        int choose_leaf_tries = 1;
+        int choose_tries = map->choose_total_tries;
+        int choose_leaf_tries = 0;
         const int descend_once = 0;
 
         if ((__u32)ruleno >= map->max_rules) {
@@ -701,6 +705,8 @@ int crush_do_rule(const struct crush_map *map,
                                                 x, numrep,
                                                 curstep->arg2,
                                                 o+osize, j,
+                                                choose_tries,
+                                                choose_leaf_tries ? choose_leaf_tries : choose_tries,
                                                 recurse_to_leaf,
                                                 descend_once, c+osize);
                                 } else {
@@ -711,8 +717,8 @@ int crush_do_rule(const struct crush_map *map,
                                                 x, numrep, numrep,
                                                 curstep->arg2,
                                                 o+osize, j,
-                                                map->choose_total_tries,
-                                                choose_leaf_tries,
+                                                choose_tries,
+                                                choose_leaf_tries ? choose_leaf_tries : 1,
                                                 recurse_to_leaf,
                                                 c+osize,
                                                 0);