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Fix hash bucket iterator

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Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
This commit is contained in:
Adam Rutkowski 2019-10-02 18:39:04 -04:00
parent a3f3a79f75
commit 94a0b5392b
1 changed files with 44 additions and 26 deletions
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70
src/concurrency/ocf_metadata_concurrency.c
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@ -255,40 +255,62 @@ void ocf_metadata_hash_unlock_wr(struct ocf_metadata_lock *metadata_lock,
ocf_metadata_end_shared_access(metadata_lock);
}
/* number of hash entries */
#define _NUM_HASH_ENTRIES req->cache->metadata.lock.num_hash_entries
/* true if hashes are monotonic */
#define _IS_MONOTONIC(req) (req->map[0].hash + req->core_line_count <= \
_NUM_HASH_ENTRIES)
/* minimal hash value */
#define _MIN_HASH(req) (_IS_MONOTONIC(req) ? req->map[0].hash : 0)
/* maximal hash value */
#define _MAX_HASH(req) (_IS_MONOTONIC(req) ? \
req->map[req->core_line_count - 1].hash : \
_NUM_HASH_ENTRIES - 1)
/* number of unique hash values in request */
#define _HASH_COUNT(req) OCF_MIN(req->core_line_count, _NUM_HASH_ENTRIES)
/* true if there is a gap in hash values */
#define _HAS_GAP(req) (_MAX_HASH(req) - _MIN_HASH(req) + 1 > _HASH_COUNT(req))
/* gap size */
#define _GAP_VAL(req) ((_MAX_HASH(req) - _MIN_HASH(req) + 1) - _HASH_COUNT(req))
/* hash value after which there is a gap */
#define _GAP_START(req) req->map[req->core_line_count - 1].hash
/* get next hash value */
#define _HASH_NEXT(req, hash) (hash + 1 + \
((_HAS_GAP(req) && hash == _GAP_START(req)) ? _GAP_VAL(req) : 0))
/*
* Iterate over hash buckets for all core lines in the request in ascending hash
* bucket value order. Each hash bucket is visited only once.
*
* @i is used as iteration counter, starting from 0
* @hash stores hash values for each iteration
* @start is internal helper variable. It set to the index of first occurence
* of hash with minimal value within the request.
*
* Example hash iteration order for _NUM_HASH_ENTRIES == 5:
* Request hashes Iteration order start
* [2, 3, 4] [2, 3, 4] 0
* [2, 3, 4, 0] [0, 2, 3, 4] 3
* [2, 3, 4, 0, 1, 2, 3, 4, 0, 1] [0, 1, 2, 3, 4] 3
* [4, 0] [0, 4] 1
* [0, 1, 2, 3, 4, 0, 1] [0, 1, 2, 3, 4] 0
* Request hashes Iteration order
* [2, 3, 4] [2, 3, 4]
* [2, 3, 4, 0] [0, 2, 3, 4]
* [2, 3, 4, 0, 1, 2, 3, 4, 0, 1] [0, 1, 2, 3, 4]
* [4, 0] [0, 4]
* [0, 1, 2, 3, 4, 0, 1] [0, 1, 2, 3, 4]
*
*/
#define for_each_req_hash_asc(req, i, hash, start) \
for (i = 0, start = (req->map[0].hash + req->core_line_count <= \
_NUM_HASH_ENTRIES) ? 0 : (_NUM_HASH_ENTRIES - req->map[0].hash)\
% _NUM_HASH_ENTRIES, hash = req->map[start].hash; \
i < OCF_MIN(req->core_line_count, _NUM_HASH_ENTRIES); \
i++, hash = req->map[(start + i) % req->core_line_count].hash)
#define for_each_req_hash_asc(req, hash) \
for (hash = _MIN_HASH(req); hash <= _MAX_HASH(req); \
hash = _HASH_NEXT(req, hash))
void ocf_req_hash_lock_rd(struct ocf_request *req)
{
unsigned i, start;
ocf_cache_line_t hash;
ocf_metadata_start_shared_access(&req->cache->metadata.lock);
for_each_req_hash_asc(req, i, hash, start) {
for_each_req_hash_asc(req, hash) {
ocf_metadata_hash_lock(&req->cache->metadata.lock, hash,
OCF_METADATA_RD);
}
@ -296,10 +318,9 @@ void ocf_req_hash_lock_rd(struct ocf_request *req)
void ocf_req_hash_unlock_rd(struct ocf_request *req)
{
unsigned i, start;
ocf_cache_line_t hash;
for_each_req_hash_asc(req, i, hash, start) {
for_each_req_hash_asc(req, hash) {
ocf_metadata_hash_unlock(&req->cache->metadata.lock, hash,
OCF_METADATA_RD);
}
@ -308,11 +329,10 @@ void ocf_req_hash_unlock_rd(struct ocf_request *req)
void ocf_req_hash_lock_wr(struct ocf_request *req)
{
unsigned i, start;
ocf_cache_line_t hash;
ocf_metadata_start_shared_access(&req->cache->metadata.lock);
for_each_req_hash_asc(req, i, hash, start) {
for_each_req_hash_asc(req, hash) {
ocf_metadata_hash_lock(&req->cache->metadata.lock, hash,
OCF_METADATA_WR);
}
@ -320,14 +340,13 @@ void ocf_req_hash_lock_wr(struct ocf_request *req)
void ocf_req_hash_lock_upgrade(struct ocf_request *req)
{
unsigned i, start;
ocf_cache_line_t hash;
for_each_req_hash_asc(req, i, hash, start) {
for_each_req_hash_asc(req, hash) {
ocf_metadata_hash_unlock(&req->cache->metadata.lock, hash,
OCF_METADATA_RD);
}
for_each_req_hash_asc(req, i, hash, start) {
for_each_req_hash_asc(req, hash) {
ocf_metadata_hash_lock(&req->cache->metadata.lock, hash,
OCF_METADATA_WR);
}
@ -335,10 +354,9 @@ void ocf_req_hash_lock_upgrade(struct ocf_request *req)
void ocf_req_hash_unlock_wr(struct ocf_request *req)
{
unsigned i, start;
ocf_cache_line_t hash;
for_each_req_hash_asc(req, i, hash, start) {
for_each_req_hash_asc(req, hash) {
ocf_metadata_hash_unlock(&req->cache->metadata.lock, hash,
OCF_METADATA_WR);
}