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numam-dpdk/lib/rcu/rte_rcu_qsbr.c
Bruce Richardson 99a2dd955f lib: remove librte_ prefix from directory names 
There is no reason for the DPDK libraries to all have 'librte_' prefix on
the directory names. This prefix makes the directory names longer and also
makes it awkward to add features referring to individual libraries in the
build - should the lib names be specified with or without the prefix.
Therefore, we can just remove the library prefix and use the library's
unique name as the directory name, i.e. 'eal' rather than 'librte_eal'

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
2021-04-21 14:04:09 +02:00

500 lines
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/* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 2018-2020 Arm Limited
*/
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <inttypes.h>
#include <errno.h>
#include <rte_common.h>
#include <rte_log.h>
#include <rte_memory.h>
#include <rte_malloc.h>
#include <rte_eal.h>
#include <rte_atomic.h>
#include <rte_per_lcore.h>
#include <rte_lcore.h>
#include <rte_errno.h>
#include <rte_ring_elem.h>
#include "rte_rcu_qsbr.h"
#include "rcu_qsbr_pvt.h"
/* Get the memory size of QSBR variable */
size_t
rte_rcu_qsbr_get_memsize(uint32_t max_threads)
{
size_t sz;
if (max_threads == 0) {
rte_log(RTE_LOG_ERR, rte_rcu_log_type,
"%s(): Invalid max_threads %u\n",
__func__, max_threads);
rte_errno = EINVAL;
return 1;
}
sz = sizeof(struct rte_rcu_qsbr);
/* Add the size of quiescent state counter array */
sz += sizeof(struct rte_rcu_qsbr_cnt) * max_threads;
/* Add the size of the registered thread ID bitmap array */
sz += __RTE_QSBR_THRID_ARRAY_SIZE(max_threads);
return sz;
}
/* Initialize a quiescent state variable */
int
rte_rcu_qsbr_init(struct rte_rcu_qsbr *v, uint32_t max_threads)
{
size_t sz;
if (v == NULL) {
rte_log(RTE_LOG_ERR, rte_rcu_log_type,
"%s(): Invalid input parameter\n", __func__);
rte_errno = EINVAL;
return 1;
}
sz = rte_rcu_qsbr_get_memsize(max_threads);
if (sz == 1)
return 1;
/* Set all the threads to offline */
memset(v, 0, sz);
v->max_threads = max_threads;
v->num_elems = RTE_ALIGN_MUL_CEIL(max_threads,
__RTE_QSBR_THRID_ARRAY_ELM_SIZE) /
__RTE_QSBR_THRID_ARRAY_ELM_SIZE;
v->token = __RTE_QSBR_CNT_INIT;
v->acked_token = __RTE_QSBR_CNT_INIT - 1;
return 0;
}
/* Register a reader thread to report its quiescent state
* on a QS variable.
*/
int
rte_rcu_qsbr_thread_register(struct rte_rcu_qsbr *v, unsigned int thread_id)
{
unsigned int i, id, success;
uint64_t old_bmap, new_bmap;
if (v == NULL || thread_id >= v->max_threads) {
rte_log(RTE_LOG_ERR, rte_rcu_log_type,
"%s(): Invalid input parameter\n", __func__);
rte_errno = EINVAL;
return 1;
}
__RTE_RCU_IS_LOCK_CNT_ZERO(v, thread_id, ERR, "Lock counter %u\n",
v->qsbr_cnt[thread_id].lock_cnt);
id = thread_id & __RTE_QSBR_THRID_MASK;
i = thread_id >> __RTE_QSBR_THRID_INDEX_SHIFT;
/* Make sure that the counter for registered threads does not
* go out of sync. Hence, additional checks are required.
*/
/* Check if the thread is already registered */
old_bmap = __atomic_load_n(__RTE_QSBR_THRID_ARRAY_ELM(v, i),
__ATOMIC_RELAXED);
if (old_bmap & 1UL << id)
return 0;
do {
new_bmap = old_bmap | (1UL << id);
success = __atomic_compare_exchange(
__RTE_QSBR_THRID_ARRAY_ELM(v, i),
&old_bmap, &new_bmap, 0,
__ATOMIC_RELEASE, __ATOMIC_RELAXED);
if (success)
__atomic_fetch_add(&v->num_threads,
1, __ATOMIC_RELAXED);
else if (old_bmap & (1UL << id))
/* Someone else registered this thread.
* Counter should not be incremented.
*/
return 0;
} while (success == 0);
return 0;
}
/* Remove a reader thread, from the list of threads reporting their
* quiescent state on a QS variable.
*/
int
rte_rcu_qsbr_thread_unregister(struct rte_rcu_qsbr *v, unsigned int thread_id)
{
unsigned int i, id, success;
uint64_t old_bmap, new_bmap;
if (v == NULL || thread_id >= v->max_threads) {
rte_log(RTE_LOG_ERR, rte_rcu_log_type,
"%s(): Invalid input parameter\n", __func__);
rte_errno = EINVAL;
return 1;
}
__RTE_RCU_IS_LOCK_CNT_ZERO(v, thread_id, ERR, "Lock counter %u\n",
v->qsbr_cnt[thread_id].lock_cnt);
id = thread_id & __RTE_QSBR_THRID_MASK;
i = thread_id >> __RTE_QSBR_THRID_INDEX_SHIFT;
/* Make sure that the counter for registered threads does not
* go out of sync. Hence, additional checks are required.
*/
/* Check if the thread is already unregistered */
old_bmap = __atomic_load_n(__RTE_QSBR_THRID_ARRAY_ELM(v, i),
__ATOMIC_RELAXED);
if (!(old_bmap & (1UL << id)))
return 0;
do {
new_bmap = old_bmap & ~(1UL << id);
/* Make sure any loads of the shared data structure are
* completed before removal of the thread from the list of
* reporting threads.
*/
success = __atomic_compare_exchange(
__RTE_QSBR_THRID_ARRAY_ELM(v, i),
&old_bmap, &new_bmap, 0,
__ATOMIC_RELEASE, __ATOMIC_RELAXED);
if (success)
__atomic_fetch_sub(&v->num_threads,
1, __ATOMIC_RELAXED);
else if (!(old_bmap & (1UL << id)))
/* Someone else unregistered this thread.
* Counter should not be incremented.
*/
return 0;
} while (success == 0);
return 0;
}
/* Wait till the reader threads have entered quiescent state. */
void
rte_rcu_qsbr_synchronize(struct rte_rcu_qsbr *v, unsigned int thread_id)
{
uint64_t t;
RTE_ASSERT(v != NULL);
t = rte_rcu_qsbr_start(v);
/* If the current thread has readside critical section,
* update its quiescent state status.
*/
if (thread_id != RTE_QSBR_THRID_INVALID)
rte_rcu_qsbr_quiescent(v, thread_id);
/* Wait for other readers to enter quiescent state */
rte_rcu_qsbr_check(v, t, true);
}
/* Dump the details of a single quiescent state variable to a file. */
int
rte_rcu_qsbr_dump(FILE *f, struct rte_rcu_qsbr *v)
{
uint64_t bmap;
uint32_t i, t, id;
if (v == NULL || f == NULL) {
rte_log(RTE_LOG_ERR, rte_rcu_log_type,
"%s(): Invalid input parameter\n", __func__);
rte_errno = EINVAL;
return 1;
}
fprintf(f, "\nQuiescent State Variable @%p\n", v);
fprintf(f, " QS variable memory size = %zu\n",
rte_rcu_qsbr_get_memsize(v->max_threads));
fprintf(f, " Given # max threads = %u\n", v->max_threads);
fprintf(f, " Current # threads = %u\n", v->num_threads);
fprintf(f, " Registered thread IDs = ");
for (i = 0; i < v->num_elems; i++) {
bmap = __atomic_load_n(__RTE_QSBR_THRID_ARRAY_ELM(v, i),
__ATOMIC_ACQUIRE);
id = i << __RTE_QSBR_THRID_INDEX_SHIFT;
while (bmap) {
t = __builtin_ctzl(bmap);
fprintf(f, "%u ", id + t);
bmap &= ~(1UL << t);
}
}
fprintf(f, "\n");
fprintf(f, " Token = %" PRIu64 "\n",
__atomic_load_n(&v->token, __ATOMIC_ACQUIRE));
fprintf(f, " Least Acknowledged Token = %" PRIu64 "\n",
__atomic_load_n(&v->acked_token, __ATOMIC_ACQUIRE));
fprintf(f, "Quiescent State Counts for readers:\n");
for (i = 0; i < v->num_elems; i++) {
bmap = __atomic_load_n(__RTE_QSBR_THRID_ARRAY_ELM(v, i),
__ATOMIC_ACQUIRE);
id = i << __RTE_QSBR_THRID_INDEX_SHIFT;
while (bmap) {
t = __builtin_ctzl(bmap);
fprintf(f, "thread ID = %u, count = %" PRIu64 ", lock count = %u\n",
id + t,
__atomic_load_n(
&v->qsbr_cnt[id + t].cnt,
__ATOMIC_RELAXED),
__atomic_load_n(
&v->qsbr_cnt[id + t].lock_cnt,
__ATOMIC_RELAXED));
bmap &= ~(1UL << t);
}
}
return 0;
}
/* Create a queue used to store the data structure elements that can
* be freed later. This queue is referred to as 'defer queue'.
*/
struct rte_rcu_qsbr_dq *
rte_rcu_qsbr_dq_create(const struct rte_rcu_qsbr_dq_parameters *params)
{
struct rte_rcu_qsbr_dq *dq;
uint32_t qs_fifo_size;
unsigned int flags;
if (params == NULL || params->free_fn == NULL ||
params->v == NULL || params->name == NULL ||
params->size == 0 || params->esize == 0 ||
(params->esize % 4 != 0)) {
rte_log(RTE_LOG_ERR, rte_rcu_log_type,
"%s(): Invalid input parameter\n", __func__);
rte_errno = EINVAL;
return NULL;
}
/* If auto reclamation is configured, reclaim limit
* should be a valid value.
*/
if ((params->trigger_reclaim_limit <= params->size) &&
(params->max_reclaim_size == 0)) {
rte_log(RTE_LOG_ERR, rte_rcu_log_type,
"%s(): Invalid input parameter, size = %u, trigger_reclaim_limit = %u, max_reclaim_size = %u\n",
__func__, params->size, params->trigger_reclaim_limit,
params->max_reclaim_size);
rte_errno = EINVAL;
return NULL;
}
dq = rte_zmalloc(NULL, sizeof(struct rte_rcu_qsbr_dq),
RTE_CACHE_LINE_SIZE);
if (dq == NULL) {
rte_errno = ENOMEM;
return NULL;
}
/* Decide the flags for the ring.
* If MT safety is requested, use RTS for ring enqueue as most
* use cases involve dq-enqueue happening on the control plane.
* Ring dequeue is always HTS due to the possibility of revert.
*/
flags = RING_F_MP_RTS_ENQ;
if (params->flags & RTE_RCU_QSBR_DQ_MT_UNSAFE)
flags = RING_F_SP_ENQ;
flags |= RING_F_MC_HTS_DEQ;
/* round up qs_fifo_size to next power of two that is not less than
* max_size.
*/
qs_fifo_size = rte_align32pow2(params->size + 1);
/* Add token size to ring element size */
dq->r = rte_ring_create_elem(params->name,
__RTE_QSBR_TOKEN_SIZE + params->esize,
qs_fifo_size, SOCKET_ID_ANY, flags);
if (dq->r == NULL) {
rte_log(RTE_LOG_ERR, rte_rcu_log_type,
"%s(): defer queue create failed\n", __func__);
rte_free(dq);
return NULL;
}
dq->v = params->v;
dq->size = params->size;
dq->esize = __RTE_QSBR_TOKEN_SIZE + params->esize;
dq->trigger_reclaim_limit = params->trigger_reclaim_limit;
dq->max_reclaim_size = params->max_reclaim_size;
dq->free_fn = params->free_fn;
dq->p = params->p;
return dq;
}
/* Enqueue one resource to the defer queue to free after the grace
* period is over.
*/
int rte_rcu_qsbr_dq_enqueue(struct rte_rcu_qsbr_dq *dq, void *e)
{
__rte_rcu_qsbr_dq_elem_t *dq_elem;
uint32_t cur_size;
if (dq == NULL || e == NULL) {
rte_log(RTE_LOG_ERR, rte_rcu_log_type,
"%s(): Invalid input parameter\n", __func__);
rte_errno = EINVAL;
return 1;
}
char data[dq->esize];
dq_elem = (__rte_rcu_qsbr_dq_elem_t *)data;
/* Start the grace period */
dq_elem->token = rte_rcu_qsbr_start(dq->v);
/* Reclaim resources if the queue size has hit the reclaim
* limit. This helps the queue from growing too large and
* allows time for reader threads to report their quiescent state.
*/
cur_size = rte_ring_count(dq->r);
if (cur_size > dq->trigger_reclaim_limit) {
rte_log(RTE_LOG_INFO, rte_rcu_log_type,
"%s(): Triggering reclamation\n", __func__);
rte_rcu_qsbr_dq_reclaim(dq, dq->max_reclaim_size,
NULL, NULL, NULL);
}
/* Enqueue the token and resource. Generating the token and
* enqueuing (token + resource) on the queue is not an
* atomic operation. When the defer queue is shared by multiple
* writers, this might result in tokens enqueued out of order
* on the queue. So, some tokens might wait longer than they
* are required to be reclaimed.
*/
memcpy(dq_elem->elem, e, dq->esize - __RTE_QSBR_TOKEN_SIZE);
/* Check the status as enqueue might fail since the other threads
* might have used up the freed space.
* Enqueue uses the configured flags when the DQ was created.
*/
if (rte_ring_enqueue_elem(dq->r, data, dq->esize) != 0) {
rte_log(RTE_LOG_ERR, rte_rcu_log_type,
"%s(): Enqueue failed\n", __func__);
/* Note that the token generated above is not used.
* Other than wasting tokens, it should not cause any
* other issues.
*/
rte_log(RTE_LOG_INFO, rte_rcu_log_type,
"%s(): Skipped enqueuing token = %" PRIu64 "\n",
__func__, dq_elem->token);
rte_errno = ENOSPC;
return 1;
}
rte_log(RTE_LOG_INFO, rte_rcu_log_type,
"%s(): Enqueued token = %" PRIu64 "\n",
__func__, dq_elem->token);
return 0;
}
/* Reclaim resources from the defer queue. */
int
rte_rcu_qsbr_dq_reclaim(struct rte_rcu_qsbr_dq *dq, unsigned int n,
unsigned int *freed, unsigned int *pending,
unsigned int *available)
{
uint32_t cnt;
__rte_rcu_qsbr_dq_elem_t *dq_elem;
if (dq == NULL || n == 0) {
rte_log(RTE_LOG_ERR, rte_rcu_log_type,
"%s(): Invalid input parameter\n", __func__);
rte_errno = EINVAL;
return 1;
}
cnt = 0;
char data[dq->esize];
/* Check reader threads quiescent state and reclaim resources */
while (cnt < n &&
rte_ring_dequeue_bulk_elem_start(dq->r, &data,
dq->esize, 1, available) != 0) {
dq_elem = (__rte_rcu_qsbr_dq_elem_t *)data;
/* Reclaim the resource */
if (rte_rcu_qsbr_check(dq->v, dq_elem->token, false) != 1) {
rte_ring_dequeue_elem_finish(dq->r, 0);
break;
}
rte_ring_dequeue_elem_finish(dq->r, 1);
rte_log(RTE_LOG_INFO, rte_rcu_log_type,
"%s(): Reclaimed token = %" PRIu64 "\n",
__func__, dq_elem->token);
dq->free_fn(dq->p, dq_elem->elem, 1);
cnt++;
}
rte_log(RTE_LOG_INFO, rte_rcu_log_type,
"%s(): Reclaimed %u resources\n", __func__, cnt);
if (freed != NULL)
*freed = cnt;
if (pending != NULL)
*pending = rte_ring_count(dq->r);
return 0;
}
/* Delete a defer queue. */
int
rte_rcu_qsbr_dq_delete(struct rte_rcu_qsbr_dq *dq)
{
unsigned int pending;
if (dq == NULL) {
rte_log(RTE_LOG_DEBUG, rte_rcu_log_type,
"%s(): Invalid input parameter\n", __func__);
return 0;
}
/* Reclaim all the resources */
rte_rcu_qsbr_dq_reclaim(dq, ~0, NULL, &pending, NULL);
if (pending != 0) {
rte_errno = EAGAIN;
return 1;
}
rte_ring_free(dq->r);
rte_free(dq);
return 0;
}
RTE_LOG_REGISTER(rte_rcu_log_type, lib.rcu, ERR);
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