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>
This commit is contained in:
Sage Weil
2012-07-30 18:15:23 -07:00
parent 1fe60e51a3
commit 546f04ef71
4 changed files with 58 additions and 7 deletions

View File

@@ -306,7 +306,6 @@ static int crush_choose(const struct crush_map *map,
int item = 0;
int itemtype;
int collide, reject;
const unsigned int orig_tries = 5; /* attempts before we fall back to search */
dprintk("CHOOSE%s bucket %d x %d outpos %d numrep %d\n", recurse_to_leaf ? "_LEAF" : "",
bucket->id, x, outpos, numrep);
@@ -351,8 +350,9 @@ static int crush_choose(const struct crush_map *map,
reject = 1;
goto reject;
}
if (flocal >= (in->size>>1) &&
flocal > orig_tries)
if (map->choose_local_fallback_tries > 0 &&
flocal >= (in->size>>1) &&
flocal > map->choose_local_fallback_tries)
item = bucket_perm_choose(in, x, r);
else
item = crush_bucket_choose(in, x, r);
@@ -422,13 +422,14 @@ reject:
ftotal++;
flocal++;
if (collide && flocal < 3)
if (collide && flocal <= map->choose_local_tries)
/* retry locally a few times */
retry_bucket = 1;
else if (flocal <= in->size + orig_tries)
else if (map->choose_local_fallback_tries > 0 &&
flocal <= in->size + map->choose_local_fallback_tries)
/* exhaustive bucket search */
retry_bucket = 1;
else if (ftotal < 20)
else if (ftotal <= map->choose_total_tries)
/* then retry descent */
retry_descent = 1;
else

View File

@@ -135,6 +135,21 @@ bad:
return -EINVAL;
}
static int skip_name_map(void **p, void *end)
{
int len;
ceph_decode_32_safe(p, end, len ,bad);
while (len--) {
int strlen;
*p += sizeof(u32);
ceph_decode_32_safe(p, end, strlen, bad);
*p += strlen;
}
return 0;
bad:
return -EINVAL;
}
static struct crush_map *crush_decode(void *pbyval, void *end)
{
struct crush_map *c;
@@ -143,6 +158,7 @@ static struct crush_map *crush_decode(void *pbyval, void *end)
void **p = &pbyval;
void *start = pbyval;
u32 magic;
u32 num_name_maps;
dout("crush_decode %p to %p len %d\n", *p, end, (int)(end - *p));
@@ -150,6 +166,11 @@ static struct crush_map *crush_decode(void *pbyval, void *end)
if (c == NULL)
return ERR_PTR(-ENOMEM);
/* set tunables to default values */
c->choose_local_tries = 2;
c->choose_local_fallback_tries = 5;
c->choose_total_tries = 19;
ceph_decode_need(p, end, 4*sizeof(u32), bad);
magic = ceph_decode_32(p);
if (magic != CRUSH_MAGIC) {
@@ -297,7 +318,25 @@ static struct crush_map *crush_decode(void *pbyval, void *end)
}
/* ignore trailing name maps. */
for (num_name_maps = 0; num_name_maps < 3; num_name_maps++) {
err = skip_name_map(p, end);
if (err < 0)
goto done;
}
/* tunables */
ceph_decode_need(p, end, 3*sizeof(u32), done);
c->choose_local_tries = ceph_decode_32(p);
c->choose_local_fallback_tries = ceph_decode_32(p);
c->choose_total_tries = ceph_decode_32(p);
dout("crush decode tunable choose_local_tries = %d",
c->choose_local_tries);
dout("crush decode tunable choose_local_fallback_tries = %d",
c->choose_local_fallback_tries);
dout("crush decode tunable choose_total_tries = %d",
c->choose_total_tries);
done:
dout("crush_decode success\n");
return c;