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crush: remove mutable part of CRUSH map

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Then add it to the working state. It would be very nice if we didn't
have to take a lock to calculate a crush placement. By moving the
permutation array into the working data, we can treat the CRUSH map as
immutable.

Reflects ceph.git commit cbcd039651c0569551cb90d26ce27e1432671f2a.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Ilya Dryomov 2017-01-31 15:55:06 +01:00
parent 1b6a78b5b9
commit 66a0e2d579
6 changed files with 218 additions and 86 deletions
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1
include/linux/ceph/osdmap.h
View File

@ -175,6 +175,7 @@ struct ceph_osdmap {
struct mutex crush_scratch_mutex;
int crush_scratch_ary[CEPH_PG_MAX_SIZE * 3];
void *crush_workspace;
};
static inline bool ceph_osd_exists(struct ceph_osdmap *map, int osd)

41
include/linux/crush/crush.h
View File

@ -135,13 +135,6 @@ struct crush_bucket {
__u32 size; /* num items */
__s32 *items;
/*
* cached random permutation: used for uniform bucket and for
* the linear search fallback for the other bucket types.
*/
__u32 perm_x; /* @x for which *perm is defined */
__u32 perm_n; /* num elements of *perm that are permuted/defined */
__u32 *perm;
};
struct crush_bucket_uniform {
@ -211,6 +204,21 @@ struct crush_map {
* device fails. */
__u8 chooseleaf_stable;
/*
* This value is calculated after decode or construction by
* the builder. It is exposed here (rather than having a
* 'build CRUSH working space' function) so that callers can
* reserve a static buffer, allocate space on the stack, or
* otherwise avoid calling into the heap allocator if they
* want to. The size of the working space depends on the map,
* while the size of the scratch vector passed to the mapper
* depends on the size of the desired result set.
*
* Nothing stops the caller from allocating both in one swell
* foop and passing in two points, though.
*/
size_t working_size;
#ifndef __KERNEL__
/*
* version 0 (original) of straw_calc has various flaws. version 1
@ -248,4 +256,23 @@ static inline int crush_calc_tree_node(int i)
return ((i+1) << 1)-1;
}
/*
* These data structures are private to the CRUSH implementation. They
* are exposed in this header file because builder needs their
* definitions to calculate the total working size.
*
* Moving this out of the crush map allow us to treat the CRUSH map as
* immutable within the mapper and removes the requirement for a CRUSH
* map lock.
*/
struct crush_work_bucket {
__u32 perm_x; /* @x for which *perm is defined */
__u32 perm_n; /* num elements of *perm that are permuted/defined */
__u32 *perm; /* Permutation of the bucket's items */
};
struct crush_work {
struct crush_work_bucket **work; /* Per-bucket working store */
};
#endif

4
include/linux/crush/mapper.h
View File

@ -15,6 +15,8 @@ extern int crush_do_rule(const struct crush_map *map,
int ruleno,
int x, int *result, int result_max,
const __u32 *weights, int weight_max,
int *scratch);
void *cwin, int *scratch);
void crush_init_workspace(const struct crush_map *map, void *v);
#endif

5
net/ceph/crush/crush.c
View File

@ -45,7 +45,6 @@ int crush_get_bucket_item_weight(const struct crush_bucket *b, int p)
void crush_destroy_bucket_uniform(struct crush_bucket_uniform *b)
{
kfree(b->h.perm);
kfree(b->h.items);
kfree(b);
}
@ -54,14 +53,12 @@ void crush_destroy_bucket_list(struct crush_bucket_list *b)
{
kfree(b->item_weights);
kfree(b->sum_weights);
kfree(b->h.perm);
kfree(b->h.items);
kfree(b);
}
void crush_destroy_bucket_tree(struct crush_bucket_tree *b)
{
kfree(b->h.perm);
kfree(b->h.items);
kfree(b->node_weights);
kfree(b);
@ -71,7 +68,6 @@ void crush_destroy_bucket_straw(struct crush_bucket_straw *b)
{
kfree(b->straws);
kfree(b->item_weights);
kfree(b->h.perm);
kfree(b->h.items);
kfree(b);
}
@ -79,7 +75,6 @@ void crush_destroy_bucket_straw(struct crush_bucket_straw *b)
void crush_destroy_bucket_straw2(struct crush_bucket_straw2 *b)
{
kfree(b->item_weights);
kfree(b->h.perm);
kfree(b->h.items);
kfree(b);
}

206
net/ceph/crush/mapper.c
View File

@ -54,7 +54,6 @@ int crush_find_rule(const struct crush_map *map, int ruleset, int type, int size
return -1;
}
/*
* bucket choose methods
*
@ -72,59 +71,60 @@ int crush_find_rule(const struct crush_map *map, int ruleset, int type, int size
* Since this is expensive, we optimize for the r=0 case, which
* captures the vast majority of calls.
*/
static int bucket_perm_choose(struct crush_bucket *bucket,
static int bucket_perm_choose(const struct crush_bucket *bucket,
struct crush_work_bucket *work,
int x, int r)
{
unsigned int pr = r % bucket->size;
unsigned int i, s;
/* start a new permutation if @x has changed */
if (bucket->perm_x != (__u32)x || bucket->perm_n == 0) {
if (work->perm_x != (__u32)x || work->perm_n == 0) {
dprintk("bucket %d new x=%d\n", bucket->id, x);
bucket->perm_x = x;
work->perm_x = x;
/* optimize common r=0 case */
if (pr == 0) {
s = crush_hash32_3(bucket->hash, x, bucket->id, 0) %
bucket->size;
bucket->perm[0] = s;
bucket->perm_n = 0xffff; /* magic value, see below */
work->perm[0] = s;
work->perm_n = 0xffff; /* magic value, see below */
goto out;
}
for (i = 0; i < bucket->size; i++)
bucket->perm[i] = i;
bucket->perm_n = 0;
} else if (bucket->perm_n == 0xffff) {
work->perm[i] = i;
work->perm_n = 0;
} else if (work->perm_n == 0xffff) {
/* clean up after the r=0 case above */
for (i = 1; i < bucket->size; i++)
bucket->perm[i] = i;
bucket->perm[bucket->perm[0]] = 0;
bucket->perm_n = 1;
work->perm[i] = i;
work->perm[work->perm[0]] = 0;
work->perm_n = 1;
}
/* calculate permutation up to pr */
for (i = 0; i < bucket->perm_n; i++)
for (i = 0; i < work->perm_n; i++)
dprintk(" perm_choose have %d: %d\n", i, bucket->perm[i]);
while (bucket->perm_n <= pr) {
unsigned int p = bucket->perm_n;
while (work->perm_n <= pr) {
unsigned int p = work->perm_n;
/* no point in swapping the final entry */
if (p < bucket->size - 1) {
i = crush_hash32_3(bucket->hash, x, bucket->id, p) %
(bucket->size - p);
if (i) {
unsigned int t = bucket->perm[p + i];
bucket->perm[p + i] = bucket->perm[p];
bucket->perm[p] = t;
unsigned int t = work->perm[p + i];
work->perm[p + i] = work->perm[p];
work->perm[p] = t;
}
dprintk(" perm_choose swap %d with %d\n", p, p+i);
}
bucket->perm_n++;
work->perm_n++;
}
for (i = 0; i < bucket->size; i++)
dprintk(" perm_choose %d: %d\n", i, bucket->perm[i]);
s = bucket->perm[pr];
s = work->perm[pr];
out:
dprintk(" perm_choose %d sz=%d x=%d r=%d (%d) s=%d\n", bucket->id,
bucket->size, x, r, pr, s);
@ -132,14 +132,14 @@ out:
}
/* uniform */
static int bucket_uniform_choose(struct crush_bucket_uniform *bucket,
int x, int r)
static int bucket_uniform_choose(const struct crush_bucket_uniform *bucket,
struct crush_work_bucket *work, int x, int r)
{
return bucket_perm_choose(&bucket->h, x, r);
return bucket_perm_choose(&bucket->h, work, x, r);
}
/* list */
static int bucket_list_choose(struct crush_bucket_list *bucket,
static int bucket_list_choose(const struct crush_bucket_list *bucket,
int x, int r)
{
int i;
@ -155,8 +155,9 @@ static int bucket_list_choose(struct crush_bucket_list *bucket,
w *= bucket->sum_weights[i];
w = w >> 16;
/*dprintk(" scaled %llx\n", w);*/
if (w < bucket->item_weights[i])
if (w < bucket->item_weights[i]) {
return bucket->h.items[i];
}
}
dprintk("bad list sums for bucket %d\n", bucket->h.id);
@ -192,7 +193,7 @@ static int terminal(int x)
return x & 1;
}
static int bucket_tree_choose(struct crush_bucket_tree *bucket,
static int bucket_tree_choose(const struct crush_bucket_tree *bucket,
int x, int r)
{
int n;
@ -224,7 +225,7 @@ static int bucket_tree_choose(struct crush_bucket_tree *bucket,
/* straw */
static int bucket_straw_choose(struct crush_bucket_straw *bucket,
static int bucket_straw_choose(const struct crush_bucket_straw *bucket,
int x, int r)
{
__u32 i;
@ -301,7 +302,7 @@ static __u64 crush_ln(unsigned int xin)
*
*/
static int bucket_straw2_choose(struct crush_bucket_straw2 *bucket,
static int bucket_straw2_choose(const struct crush_bucket_straw2 *bucket,
int x, int r)
{
unsigned int i, high = 0;
@ -344,37 +345,42 @@ static int bucket_straw2_choose(struct crush_bucket_straw2 *bucket,
high_draw = draw;
}
}
return bucket->h.items[high];
}
static int crush_bucket_choose(struct crush_bucket *in, int x, int r)
static int crush_bucket_choose(const struct crush_bucket *in,
struct crush_work_bucket *work,
int x, int r)
{
dprintk(" crush_bucket_choose %d x=%d r=%d\n", in->id, x, r);
BUG_ON(in->size == 0);
switch (in->alg) {
case CRUSH_BUCKET_UNIFORM:
return bucket_uniform_choose((struct crush_bucket_uniform *)in,
x, r);
return bucket_uniform_choose(
(const struct crush_bucket_uniform *)in,
work, x, r);
case CRUSH_BUCKET_LIST:
return bucket_list_choose((struct crush_bucket_list *)in,
return bucket_list_choose((const struct crush_bucket_list *)in,
x, r);
case CRUSH_BUCKET_TREE:
return bucket_tree_choose((struct crush_bucket_tree *)in,
return bucket_tree_choose((const struct crush_bucket_tree *)in,
x, r);
case CRUSH_BUCKET_STRAW:
return bucket_straw_choose((struct crush_bucket_straw *)in,
x, r);
return bucket_straw_choose(
(const struct crush_bucket_straw *)in,
x, r);
case CRUSH_BUCKET_STRAW2:
return bucket_straw2_choose((struct crush_bucket_straw2 *)in,
x, r);
return bucket_straw2_choose(
(const struct crush_bucket_straw2 *)in,
x, r);
default:
dprintk("unknown bucket %d alg %d\n", in->id, in->alg);
return in->items[0];
}
}
/*
* true if device is marked "out" (failed, fully offloaded)
* of the cluster
@ -416,7 +422,8 @@ static int is_out(const struct crush_map *map,
* @parent_r: r value passed from the parent
*/
static int crush_choose_firstn(const struct crush_map *map,
struct crush_bucket *bucket,
struct crush_work *work,
const struct crush_bucket *bucket,
const __u32 *weight, int weight_max,
int x, int numrep, int type,
int *out, int outpos,
@ -434,7 +441,7 @@ static int crush_choose_firstn(const struct crush_map *map,
int rep;
unsigned int ftotal, flocal;
int retry_descent, retry_bucket, skip_rep;
struct crush_bucket *in = bucket;
const struct crush_bucket *in = bucket;
int r;
int i;
int item = 0;
@ -473,9 +480,13 @@ static int crush_choose_firstn(const struct crush_map *map,
if (local_fallback_retries > 0 &&
flocal >= (in->size>>1) &&
flocal > local_fallback_retries)
item = bucket_perm_choose(in, x, r);
item = bucket_perm_choose(
in, work->work[-1-in->id],
x, r);
else
item = crush_bucket_choose(in, x, r);
item = crush_bucket_choose(
in, work->work[-1-in->id],
x, r);
if (item >= map->max_devices) {
dprintk(" bad item %d\n", item);
skip_rep = 1;
@ -518,19 +529,21 @@ static int crush_choose_firstn(const struct crush_map *map,
sub_r = r >> (vary_r-1);
else
sub_r = 0;
if (crush_choose_firstn(map,
map->buckets[-1-item],
weight, weight_max,
x, stable ? 1 : outpos+1, 0,
out2, outpos, count,
recurse_tries, 0,
local_retries,
local_fallback_retries,
0,
vary_r,
stable,
NULL,
sub_r) <= outpos)
if (crush_choose_firstn(
map,
work,
map->buckets[-1-item],
weight, weight_max,
x, stable ? 1 : outpos+1, 0,
out2, outpos, count,
recurse_tries, 0,
local_retries,
local_fallback_retries,
0,
vary_r,
stable,
NULL,
sub_r) <= outpos)
/* didn't get leaf */
reject = 1;
} else {
@ -600,7 +613,8 @@ reject:
*
*/
static void crush_choose_indep(const struct crush_map *map,
struct crush_bucket *bucket,
struct crush_work *work,
const struct crush_bucket *bucket,
const __u32 *weight, int weight_max,
int x, int left, int numrep, int type,
int *out, int outpos,
@ -610,7 +624,7 @@ static void crush_choose_indep(const struct crush_map *map,
int *out2,
int parent_r)
{
struct crush_bucket *in = bucket;
const struct crush_bucket *in = bucket;
int endpos = outpos + left;
int rep;
unsigned int ftotal;
@ -678,7 +692,9 @@ static void crush_choose_indep(const struct crush_map *map,
break;
}
item = crush_bucket_choose(in, x, r);
item = crush_bucket_choose(
in, work->work[-1-in->id],
x, r);
if (item >= map->max_devices) {
dprintk(" bad item %d\n", item);
out[rep] = CRUSH_ITEM_NONE;
@ -724,13 +740,15 @@ static void crush_choose_indep(const struct crush_map *map,
if (recurse_to_leaf) {
if (item < 0) {
crush_choose_indep(map,
map->buckets[-1-item],
weight, weight_max,
x, 1, numrep, 0,
out2, rep,
recurse_tries, 0,
0, NULL, r);
crush_choose_indep(
map,
work,
map->buckets[-1-item],
weight, weight_max,
x, 1, numrep, 0,
out2, rep,
recurse_tries, 0,
0, NULL, r);
if (out2[rep] == CRUSH_ITEM_NONE) {
/* placed nothing; no leaf */
break;
@ -781,6 +799,53 @@ static void crush_choose_indep(const struct crush_map *map,
#endif
}
/*
* This takes a chunk of memory and sets it up to be a shiny new
* working area for a CRUSH placement computation. It must be called
* on any newly allocated memory before passing it in to
* crush_do_rule. It may be used repeatedly after that, so long as the
* map has not changed. If the map /has/ changed, you must make sure
* the working size is no smaller than what was allocated and re-run
* crush_init_workspace.
*
* If you do retain the working space between calls to crush, make it
* thread-local.
*/
void crush_init_workspace(const struct crush_map *map, void *v)
{
struct crush_work *w = v;
__s32 b;
/*
* We work by moving through the available space and setting
* values and pointers as we go.
*
* It's a bit like Forth's use of the 'allot' word since we
* set the pointer first and then reserve the space for it to
* point to by incrementing the point.
*/
v += sizeof(struct crush_work *);
w->work = v;
v += map->max_buckets * sizeof(struct crush_work_bucket *);
for (b = 0; b < map->max_buckets; ++b) {
if (!map->buckets[b])
continue;
w->work[b] = v;
switch (map->buckets[b]->alg) {
default:
v += sizeof(struct crush_work_bucket);
break;
}
w->work[b]->perm_x = 0;
w->work[b]->perm_n = 0;
w->work[b]->perm = v;
v += map->buckets[b]->size * sizeof(__u32);
}
BUG_ON(v - (void *)w != map->working_size);
}
/**
* crush_do_rule - calculate a mapping with the given input and rule
* @map: the crush_map
@ -790,14 +855,16 @@ static void crush_choose_indep(const struct crush_map *map,
* @result_max: maximum result size
* @weight: weight vector (for map leaves)
* @weight_max: size of weight vector
* @cwin: pointer to at least map->working_size bytes of memory
* @scratch: scratch vector for private use; must be >= 3 * result_max
*/
int crush_do_rule(const struct crush_map *map,
int ruleno, int x, int *result, int result_max,
const __u32 *weight, int weight_max,
int *scratch)
void *cwin, int *scratch)
{
int result_len;
struct crush_work *cw = cwin;
int *a = scratch;
int *b = scratch + result_max;
int *c = scratch + result_max*2;
@ -807,7 +874,7 @@ int crush_do_rule(const struct crush_map *map,
int *o;
int osize;
int *tmp;
struct crush_rule *rule;
const struct crush_rule *rule;
__u32 step;
int i, j;
int numrep;
@ -840,7 +907,7 @@ int crush_do_rule(const struct crush_map *map,
for (step = 0; step < rule->len; step++) {
int firstn = 0;
struct crush_rule_step *curstep = &rule->steps[step];
const struct crush_rule_step *curstep = &rule->steps[step];
switch (curstep->op) {
case CRUSH_RULE_TAKE:
@ -936,6 +1003,7 @@ int crush_do_rule(const struct crush_map *map,
recurse_tries = choose_tries;
osize += crush_choose_firstn(
map,
cw,
map->buckets[bno],
weight, weight_max,
x, numrep,
@ -956,6 +1024,7 @@ int crush_do_rule(const struct crush_map *map,
numrep : (result_max-osize));
crush_choose_indep(
map,
cw,
map->buckets[bno],
weight, weight_max,
x, out_size, numrep,
@ -997,5 +1066,6 @@ int crush_do_rule(const struct crush_map *map,
break;
}
}
return result_len;
}

47
net/ceph/osdmap.c
View File

@ -153,6 +153,32 @@ bad:
return -EINVAL;
}
static void crush_finalize(struct crush_map *c)
{
__s32 b;
/* Space for the array of pointers to per-bucket workspace */
c->working_size = sizeof(struct crush_work) +
c->max_buckets * sizeof(struct crush_work_bucket *);
for (b = 0; b < c->max_buckets; b++) {
if (!c->buckets[b])
continue;
switch (c->buckets[b]->alg) {
default:
/*
* The base case, permutation variables and
* the pointer to the permutation array.
*/
c->working_size += sizeof(struct crush_work_bucket);
break;
}
/* Every bucket has a permutation array. */
c->working_size += c->buckets[b]->size * sizeof(__u32);
}
}
static struct crush_map *crush_decode(void *pbyval, void *end)
{
struct crush_map *c;
@ -246,10 +272,6 @@ static struct crush_map *crush_decode(void *pbyval, void *end)
b->items = kcalloc(b->size, sizeof(__s32), GFP_NOFS);
if (b->items == NULL)
goto badmem;
b->perm = kcalloc(b->size, sizeof(u32), GFP_NOFS);
if (b->perm == NULL)
goto badmem;
b->perm_n = 0;
ceph_decode_need(p, end, b->size*sizeof(u32), bad);
for (j = 0; j < b->size; j++)
@ -368,6 +390,8 @@ static struct crush_map *crush_decode(void *pbyval, void *end)
dout("crush decode tunable chooseleaf_stable = %d\n",
c->chooseleaf_stable);
crush_finalize(c);
done:
dout("crush_decode success\n");
return c;
@ -753,6 +777,7 @@ void ceph_osdmap_destroy(struct ceph_osdmap *map)
kfree(map->osd_weight);
kfree(map->osd_addr);
kfree(map->osd_primary_affinity);
kfree(map->crush_workspace);
kfree(map);
}
@ -810,12 +835,23 @@ static int osdmap_set_max_osd(struct ceph_osdmap *map, int max)
static int osdmap_set_crush(struct ceph_osdmap *map, struct crush_map *crush)
{
void *workspace;
if (IS_ERR(crush))
return PTR_ERR(crush);
workspace = kmalloc(crush->working_size, GFP_NOIO);
if (!workspace) {
crush_destroy(crush);
return -ENOMEM;
}
crush_init_workspace(crush, workspace);
if (map->crush)
crush_destroy(map->crush);
kfree(map->crush_workspace);
map->crush = crush;
map->crush_workspace = workspace;
return 0;
}
@ -1940,7 +1976,8 @@ static int do_crush(struct ceph_osdmap *map, int ruleno, int x,
mutex_lock(&map->crush_scratch_mutex);
r = crush_do_rule(map->crush, ruleno, x, result, result_max,
weight, weight_max, map->crush_scratch_ary);
weight, weight_max, map->crush_workspace,
map->crush_scratch_ary);
mutex_unlock(&map->crush_scratch_mutex);
return r;