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crush: use breadth-first search for indep mode 

Reflects ceph.git commit 86e978036a4ecbac4c875e7c00f6c5bbe37282d3.

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 21:19:25 +02:00
parent c6d98a603a
commit 9a3b490a20
2 changed files with 165 additions and 10 deletions
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3
include/linux/crush/crush.h
View File

@ -22,7 +22,8 @@
#define CRUSH_MAX_DEPTH 10 /* max crush hierarchy depth */
#define CRUSH_ITEM_UNDEF 0x7fffffff /* undefined result */
#define CRUSH_ITEM_UNDEF 0x7ffffffe /* undefined result (internal use only) */
#define CRUSH_ITEM_NONE 0x7fffffff /* no result */
/*
* CRUSH uses user-defined "rules" to describe how inputs should be

154
net/ceph/crush/mapper.c
View File

@ -473,6 +473,148 @@ static int crush_choose(const struct crush_map *map,
}
/**
* choose indep: alternative breadth-first positionally stable mapping
*
*/
static void crush_choose_indep(const struct crush_map *map,
struct crush_bucket *bucket,
const __u32 *weight, int weight_max,
int x, int numrep, int type,
int *out, int outpos,
int recurse_to_leaf,
int *out2)
{
struct crush_bucket *in = bucket;
int left = numrep - outpos;
int rep;
unsigned int ftotal;
int r;
int i;
int item = 0;
int itemtype;
int collide;
dprintk("CHOOSE%s INDEP bucket %d x %d outpos %d numrep %d\n", recurse_to_leaf ? "_LEAF" : "",
bucket->id, x, outpos, numrep);
/* initially my result is undefined */
for (rep = outpos; rep < numrep; rep++) {
out[rep] = CRUSH_ITEM_UNDEF;
if (out2)
out2[rep] = CRUSH_ITEM_UNDEF;
}
for (ftotal = 0; left > 0 && ftotal < map->choose_total_tries; ftotal++) {
for (rep = outpos; rep < numrep; rep++) {
if (out[rep] != CRUSH_ITEM_UNDEF)
continue;
in = bucket; /* initial bucket */
/* choose through intervening buckets */
for (;;) {
r = rep;
/* be careful */
if (in->alg == CRUSH_BUCKET_UNIFORM &&
in->size % numrep == 0)
/* r'=r+(n+1)*f_total */
r += (numrep+1) * ftotal;
else
/* r' = r + n*f_total */
r += numrep * ftotal;
/* bucket choose */
if (in->size == 0) {
dprintk(" empty bucket\n");
break;
}
item = crush_bucket_choose(in, x, r);
if (item >= map->max_devices) {
dprintk(" bad item %d\n", item);
out[rep] = CRUSH_ITEM_NONE;
if (out2)
out2[rep] = CRUSH_ITEM_NONE;
left--;
break;
}
/* desired type? */
if (item < 0)
itemtype = map->buckets[-1-item]->type;
else
itemtype = 0;
dprintk(" item %d type %d\n", item, itemtype);
/* keep going? */
if (itemtype != type) {
if (item >= 0 ||
(-1-item) >= map->max_buckets) {
dprintk(" bad item type %d\n", type);
out[rep] = CRUSH_ITEM_NONE;
if (out2)
out2[rep] =
CRUSH_ITEM_NONE;
left--;
break;
}
in = map->buckets[-1-item];
continue;
}
/* collision? */
collide = 0;
for (i = outpos; i < numrep; i++) {
if (out[i] == item) {
collide = 1;
break;
}
}
if (collide)
break;
if (recurse_to_leaf) {
if (item < 0) {
crush_choose_indep(map,
map->buckets[-1-item],
weight, weight_max,
x, rep+1, 0,
out2, rep,
0, NULL);
if (out2[rep] == CRUSH_ITEM_NONE) {
/* placed nothing; no leaf */
break;
}
} else {
/* we already have a leaf! */
out2[rep] = item;
}
}
/* out? */
if (itemtype == 0 &&
is_out(map, weight, weight_max, item, x))
break;
/* yay! */
out[rep] = item;
left--;
break;
}
}
}
for (rep = outpos; rep < numrep; rep++) {
if (out[rep] == CRUSH_ITEM_UNDEF) {
out[rep] = CRUSH_ITEM_NONE;
}
if (out2 && out2[rep] == CRUSH_ITEM_UNDEF) {
out2[rep] = CRUSH_ITEM_NONE;
}
}
}
/**
* crush_do_rule - calculate a mapping with the given input and rule
* @map: the crush_map
@ -556,6 +698,7 @@ int crush_do_rule(const struct crush_map *map,
continue;
}
j = 0;
if (firstn) {
osize += crush_choose(map,
map->buckets[-1-w[i]],
weight, weight_max,
@ -565,6 +708,17 @@ int crush_do_rule(const struct crush_map *map,
firstn,
recurse_to_leaf,
descend_once, c+osize);
} else {
crush_choose_indep(map,
map->buckets[-1-w[i]],
weight, weight_max,
x, numrep,
curstep->arg2,
o+osize, j,
recurse_to_leaf,
c+osize);
osize += numrep;
}
}
if (recurse_to_leaf)