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crush: generalize descend_once

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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: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
This commit is contained in:
Ilya Dryomov 2013-12-24 21:19:26 +02:00
parent 917edad5d1
commit d390bb2a83
1 changed files with 14 additions and 11 deletions
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25
net/ceph/crush/mapper.c
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@ -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);