Commit d390bb2a authored by Ilya Dryomov's avatar Ilya Dryomov
Browse files

crush: generalize descend_once 



The legacy behavior is to make the normal number of tries for the
recursive chooseleaf call.  The descend_once tunable changed this to
making a single try and bail if we get a reject (note that it is
impossible to collide in the recursive case).

The new set_chooseleaf_tries lets you select the number of recursive
chooseleaf attempts for indep mode, or default to 1.  Use the same
behavior for firstn, except default to total_tries when the legacy
tunables are set (for compatibility).  This makes the rule step
override the (new) default of 1 recursive attempt, keeping behavior
consistent with indep mode.

Reflects ceph.git commit 685c6950ef3df325ef04ce7c986e36ca2514c5f1.

Signed-off-by: default avatarIlya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: default avatarSage Weil <sage@inktank.com>
parent 917edad5

net/ceph/crush/mapper.c

+14 −11
Original line number Diff line number Diff line
@@ -291,7 +291,6 @@ static int is_out(const struct crush_map *map, 
 * @out: pointer to output vector

 * @outpos: our position in that vector

 * @recurse_to_leaf: true if we want one device under each item of given type

 * @descend_once: true if we should only try one descent before giving up

 * @out2: second output vector for leaf items (if @recurse_to_leaf)

 */

static int crush_choose_firstn(const struct crush_map *map,
@@ -302,7 +301,7 @@ static int crush_choose_firstn(const struct crush_map *map, 
			       unsigned int attempts,

			       unsigned int recurse_attempts,

			       int recurse_to_leaf,

			       int descend_once, int *out2)

			       int *out2)

{

	int rep;

	unsigned int ftotal, flocal;
@@ -389,7 +388,6 @@ static int crush_choose_firstn(const struct crush_map *map, 
							 out2, outpos,

							 recurse_attempts, 0,

							 0,

							 map->chooseleaf_descend_once,

							 NULL) <= outpos)

							/* didn't get leaf */

							reject = 1;
@@ -414,10 +412,7 @@ reject: 
					ftotal++;

					flocal++;



					if (reject && descend_once)

						/* let outer call try again */

						skip_rep = 1;

					else if (collide && flocal <= map->choose_local_tries)

					if (collide && flocal <= map->choose_local_tries)

						/* retry locally a few times */

						retry_bucket = 1;

					else if (map->choose_local_fallback_tries > 0 &&
@@ -639,7 +634,6 @@ int crush_do_rule(const struct crush_map *map, 
	int numrep;

	int choose_tries = map->choose_total_tries;

	int choose_leaf_tries = 0;

	const int descend_once = 0;



	if ((__u32)ruleno >= map->max_rules) {

		dprintk(" bad ruleno %d\n", ruleno);
@@ -703,6 +697,14 @@ int crush_do_rule(const struct crush_map *map, 
				}

				j = 0;

				if (firstn) {

					int recurse_tries;

					if (choose_leaf_tries)

						recurse_tries =

							choose_leaf_tries;

					else if (map->chooseleaf_descend_once)

						recurse_tries = 1;

					else

						recurse_tries = choose_tries;

					osize += crush_choose_firstn(

						map,

						map->buckets[-1-w[i]],
@@ -711,9 +713,9 @@ int crush_do_rule(const struct crush_map *map, 
						curstep->arg2,

						o+osize, j,

						choose_tries,

						choose_leaf_tries ? choose_leaf_tries : choose_tries,

						recurse_tries,

						recurse_to_leaf,

						descend_once, c+osize);

						c+osize);

				} else {

					crush_choose_indep(

						map,
@@ -723,7 +725,8 @@ int crush_do_rule(const struct crush_map *map, 
						curstep->arg2,

						o+osize, j,

						choose_tries,

						choose_leaf_tries ? choose_leaf_tries : 1,

						choose_leaf_tries ?

						   choose_leaf_tries : 1,

						recurse_to_leaf,

						c+osize,

						0);

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