Add resource reclamation APIs to make it simple for applications
and libraries to integrate rte_rcu library.
Signed-off-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
Reviewed-by: Ola Liljedhal <ola.liljed...@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com>
---
lib/librte_rcu/Makefile | 2 +-
lib/librte_rcu/meson.build | 2 +
lib/librte_rcu/rcu_qsbr_pvt.h | 57 +++++++
lib/librte_rcu/rte_rcu_qsbr.c | 243 ++++++++++++++++++++++++++++-
lib/librte_rcu/rte_rcu_qsbr.h | 188 ++++++++++++++++++++++
lib/librte_rcu/rte_rcu_version.map | 4 +
lib/meson.build | 6 +-
7 files changed, 498 insertions(+), 4 deletions(-)
create mode 100644 lib/librte_rcu/rcu_qsbr_pvt.h
diff --git a/lib/librte_rcu/Makefile b/lib/librte_rcu/Makefile
index c4bb28d77..95f8a57e2 100644
--- a/lib/librte_rcu/Makefile
+++ b/lib/librte_rcu/Makefile
@@ -8,7 +8,7 @@ LIB = librte_rcu.a
CFLAGS += -DALLOW_EXPERIMENTAL_API
CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3
-LDLIBS += -lrte_eal
+LDLIBS += -lrte_eal -lrte_ring
EXPORT_MAP := rte_rcu_version.map
diff --git a/lib/librte_rcu/meson.build b/lib/librte_rcu/meson.build
index 62920ba02..e280b29c1 100644
--- a/lib/librte_rcu/meson.build
+++ b/lib/librte_rcu/meson.build
@@ -10,3 +10,5 @@ headers = files('rte_rcu_qsbr.h')
if cc.get_id() == 'clang' and dpdk_conf.get('RTE_ARCH_64') == false
ext_deps += cc.find_library('atomic')
endif
+
+deps += ['ring']
diff --git a/lib/librte_rcu/rcu_qsbr_pvt.h b/lib/librte_rcu/rcu_qsbr_pvt.h
new file mode 100644
index 000000000..413f28587
--- /dev/null
+++ b/lib/librte_rcu/rcu_qsbr_pvt.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright (c) 2019 Arm Limited
+ */
+
+#ifndef _RTE_RCU_QSBR_PVT_H_
+#define _RTE_RCU_QSBR_PVT_H_
+
+/**
+ * This file is private to the RCU library. It should not be included
+ * by the user of this library.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <rte_ring.h>
+#include <rte_ring_elem.h>
+
+#include "rte_rcu_qsbr.h"
+
+/* RTE defer queue structure.
+ * This structure holds the defer queue. The defer queue is used to
+ * hold the deleted entries from the data structure that are not
+ * yet freed.
+ */
+struct rte_rcu_qsbr_dq {
+ struct rte_rcu_qsbr *v; /**< RCU QSBR variable used by this queue.*/
+ struct rte_ring *r; /**< RCU QSBR defer queue. */
+ uint32_t size;
+ /**< Number of elements in the defer queue */
+ uint32_t esize;
+ /**< Size (in bytes) of data, including the token, stored on the
+ * defer queue.
+ */
+ uint32_t trigger_reclaim_limit;
+ /**< Trigger automatic reclamation after the defer queue
+ * has atleast these many resources waiting.
+ */
+ uint32_t max_reclaim_size;
+ /**< Reclaim at the max these many resources during auto
+ * reclamation.
+ */
+ rte_rcu_qsbr_free_resource_t free_fn;
+ /**< Function to call to free the resource. */
+ void *p;
+ /**< Pointer passed to the free function. Typically, this is the
+ * pointer to the data structure to which the resource to free
+ * belongs.
+ */
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_RCU_QSBR_PVT_H_ */
diff --git a/lib/librte_rcu/rte_rcu_qsbr.c b/lib/librte_rcu/rte_rcu_qsbr.c
index 2f3fad776..e8c1e386f 100644
--- a/lib/librte_rcu/rte_rcu_qsbr.c
+++ b/lib/librte_rcu/rte_rcu_qsbr.c
@@ -1,6 +1,6 @@
/* SPDX-License-Identifier: BSD-3-Clause
*
- * Copyright (c) 2018 Arm Limited
+ * Copyright (c) 2018-2019 Arm Limited
*/
#include <stdio.h>
@@ -18,8 +18,10 @@
#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
@@ -270,6 +272,245 @@ rte_rcu_qsbr_dump(FILE *f, struct rte_rcu_qsbr *v)
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)
+{
+ uint64_t token;
+ uint32_t cur_size, free_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;
+ }
+
+ /* Start the grace period */
+ token = rte_rcu_qsbr_start(dq->v);
+
+ /* Reclaim resources if the queue is 1/8th full. 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);
+ }
+
+ /* Check if there is space for atleast 1 resource */
+ free_size = rte_ring_free_count(dq->r);
+ if (!free_size) {
+ rte_log(RTE_LOG_ERR, rte_rcu_log_type,
+ "%s(): Defer queue is full\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__, token);
+
+ rte_errno = ENOSPC;
+ return 1;
+ }
+
+ /* Enqueue the token and resource. Generating the token
+ * and enqueuing (token + resource) on the queue is not an
+ * atomic operation. 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.
+ */
+ char data[dq->esize];
+ memcpy(data, &token, __RTE_QSBR_TOKEN_SIZE);
+ memcpy(data + __RTE_QSBR_TOKEN_SIZE, e,
+ dq->esize - __RTE_QSBR_TOKEN_SIZE);
+ /* Check the status as enqueue might fail since the other thread
+ * 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__, token);
+
+ rte_errno = ENOSPC;
+ return 1;
+ }
+
+ rte_log(RTE_LOG_INFO, rte_rcu_log_type,
+ "%s(): Enqueued token = %"PRIu64"\n", __func__, 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)
+{
+ uint32_t cnt;
+ uint64_t token;
+
+ 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 e[dq->esize];
+ /* Check reader threads quiescent state and reclaim resources */
+ while ((cnt < n) &&
+ (rte_ring_dequeue_bulk_elem_start(dq->r, e,
+ dq->esize, 1, NULL) != 0)) {
+ memcpy(&token, e, sizeof(uint64_t));
+
+ /* Reclaim the resource */
+ if (rte_rcu_qsbr_check(dq->v, token, false) != 1) {
+ rte_ring_dequeue_finish(dq->r, 0);
+ break;
+ }
+ rte_ring_dequeue_finish(dq->r, 1);
+
+ rte_log(RTE_LOG_INFO, rte_rcu_log_type,
+ "%s(): Reclaimed token = %"PRIu64"\n",
+ __func__, *(uint64_t *)e);
+
+ dq->free_fn(dq->p, e + __RTE_QSBR_TOKEN_SIZE);
+
+ 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_ERR, rte_rcu_log_type,
+ "%s(): Invalid input parameter\n", __func__);
+ rte_errno = EINVAL;
+
+ return 1;
+ }
+
+ /* Reclaim all the resources */
+ rte_rcu_qsbr_dq_reclaim(dq, ~0, NULL, &pending);
+ if (pending != 0) {
+ rte_errno = EAGAIN;
+
+ return 1;
+ }
+
+ rte_ring_free(dq->r);
+ rte_free(dq);
+
+ return 0;
+}
+
int rte_rcu_log_type;
RTE_INIT(rte_rcu_register)
diff --git a/lib/librte_rcu/rte_rcu_qsbr.h b/lib/librte_rcu/rte_rcu_qsbr.h
index 0b5585925..213f9b029 100644
--- a/lib/librte_rcu/rte_rcu_qsbr.h
+++ b/lib/librte_rcu/rte_rcu_qsbr.h
@@ -34,6 +34,7 @@ extern "C" {
#include <rte_lcore.h>
#include <rte_debug.h>
#include <rte_atomic.h>
+#include <rte_ring.h>
extern int rte_rcu_log_type;
@@ -84,6 +85,7 @@ struct rte_rcu_qsbr_cnt {
#define __RTE_QSBR_CNT_THR_OFFLINE 0
#define __RTE_QSBR_CNT_INIT 1
#define __RTE_QSBR_CNT_MAX ((uint64_t)~0)
+#define __RTE_QSBR_TOKEN_SIZE sizeof(uint64_t)
/* RTE Quiescent State variable structure.
* This structure has two elements that vary in size based on the
@@ -114,6 +116,84 @@ struct rte_rcu_qsbr {
*/
} __rte_cache_aligned;
+/**
+ * Call back function called to free the resources.
+ *
+ * @param p
+ * Pointer provided while creating the defer queue
+ * @param e
+ * Pointer to the resource data stored on the defer queue
+ *
+ * @return
+ * None
+ */
+typedef void (*rte_rcu_qsbr_free_resource_t)(void *p, void *e);
+
+#define RTE_RCU_QSBR_DQ_NAMESIZE RTE_RING_NAMESIZE
+
+/**
+ * Various flags supported.
+ */
+/**< Enqueue and reclaim operations are multi-thread safe by default.
+ * The call back functions registered to free the resources are
+ * assumed to be multi-thread safe.
+ * Set this flag is multi-thread safety is not required.
+ */
+#define RTE_RCU_QSBR_DQ_MT_UNSAFE 1
+
+/**
+ * Parameters used when creating the defer queue.
+ */
+struct rte_rcu_qsbr_dq_parameters {
+ const char *name;
+ /**< Name of the queue. */
+ uint32_t flags;
+ /**< Flags to control API behaviors */
+ uint32_t size;
+ /**< Number of entries in queue. Typically, this will be
+ * the same as the maximum number of entries supported in the
+ * lock free data structure.
+ * Data structures with unbounded number of entries is not
+ * supported currently.
+ */
+ uint32_t esize;
+ /**< Size (in bytes) of each element in the defer queue.
+ * This has to be multiple of 4B.
+ */
+ uint32_t trigger_reclaim_limit;
+ /**< Trigger automatic reclamation after the defer queue
+ * has atleast these many resources waiting. This auto
+ * reclamation is triggered in rte_rcu_qsbr_dq_enqueue API
+ * call.
+ * If this is greater than 'size', auto reclamation is
+ * not triggered.
+ * If this is set to 0, auto reclamation is triggered
+ * in every call to rte_rcu_qsbr_dq_enqueue API.
+ */
+ uint32_t max_reclaim_size;
+ /**< When automatic reclamation is enabled, reclaim at the max
+ * these many resources. This should contain a valid value, if
+ * auto reclamation is on. Setting this to 'size' or greater will
+ * reclaim all possible resources currently on the defer queue.
+ */
+ rte_rcu_qsbr_free_resource_t free_fn;
+ /**< Function to call to free the resource. */
+ void *p;
+ /**< Pointer passed to the free function. Typically, this is the
+ * pointer to the data structure to which the resource to free
+ * belongs. This can be NULL.
+ */
+ struct rte_rcu_qsbr *v;
+ /**< RCU QSBR variable to use for this defer queue */
+};
+
+/* RTE defer queue structure.
+ * This structure holds the defer queue. The defer queue is used to
+ * hold the deleted entries from the data structure that are not
+ * yet freed.
+ */
+struct rte_rcu_qsbr_dq;
+
/**
* @warning
* @b EXPERIMENTAL: this API may change without prior notice
@@ -692,6 +772,114 @@ __rte_experimental
int
rte_rcu_qsbr_dump(FILE *f, struct rte_rcu_qsbr *v);
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Create a queue used to store the data structure elements that can
+ * be freed later. This queue is referred to as 'defer queue'.
+ *
+ * @param params
+ * Parameters to create a defer queue.
+ * @return
+ * On success - Valid pointer to defer queue
+ * On error - NULL
+ * Possible rte_errno codes are:
+ * - EINVAL - NULL parameters are passed
+ * - ENOMEM - Not enough memory
+ */
+__rte_experimental
+struct rte_rcu_qsbr_dq *
+rte_rcu_qsbr_dq_create(const struct rte_rcu_qsbr_dq_parameters *params);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Enqueue one resource to the defer queue and start the grace period.
+ * The resource will be freed later after at least one grace period
+ * is over.
+ *
+ * If the defer queue is full, it will attempt to reclaim resources.
+ * It will also reclaim resources at regular intervals to avoid
+ * the defer queue from growing too big.
+ *
+ * Multi-thread safety is provided as the defer queue configuration.
+ * When multi-thread safety is requested, it is possible that the
+ * resources are not stored in their order of deletion. This results
+ * in resources being held in the defer queue longer than they should.
+ *
+ * @param dq
+ * Defer queue to allocate an entry from.
+ * @param e
+ * Pointer to resource data to copy to the defer queue. The size of
+ * the data to copy is equal to the element size provided when the
+ * defer queue was created.
+ * @return
+ * On success - 0
+ * On error - 1 with rte_errno set to
+ * - EINVAL - NULL parameters are passed
+ * - ENOSPC - Defer queue is full. This condition can not happen
+ * if the defer queue size is equal (or larger) than the
+ * number of elements in the data structure.
+ */
+__rte_experimental
+int
+rte_rcu_qsbr_dq_enqueue(struct rte_rcu_qsbr_dq *dq, void *e);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Free quesed resources from the defer queue.
+ *
+ * This API is multi-thread safe.
+ *
+ * @param dq
+ * Defer queue to free an entry from.
+ * @param n
+ * Maximum number of resources to free.
+ * @param freed
+ * Number of resources that were freed.
+ * @param pending
+ * Number of resources pending on the defer queue. This number might not
+ * be acurate if multi-thread safety is configured.
+ * @return
+ * On successful reclamation of at least 1 resource - 0
+ * On error - 1 with rte_errno set to
+ * - EINVAL - NULL parameters are passed
+ */
+__rte_experimental
+int
+rte_rcu_qsbr_dq_reclaim(struct rte_rcu_qsbr_dq *dq, unsigned int n,
+ unsigned int *freed, unsigned int *pending);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Delete a defer queue.
+ *
+ * It tries to reclaim all the resources on the defer queue.
+ * If any of the resources have not completed the grace period
+ * the reclamation stops and returns immediately. The rest of
+ * the resources are not reclaimed and the defer queue is not
+ * freed.
+ *
+ * @param dq
+ * Defer queue to delete.
+ * @return
+ * On success - 0
+ * On error - 1
+ * Possible rte_errno codes are:
+ * - EINVAL - NULL parameters are passed
+ * - EAGAIN - Some of the resources have not completed at least 1 grace
+ * period, try again.
+ */
+__rte_experimental
+int
+rte_rcu_qsbr_dq_delete(struct rte_rcu_qsbr_dq *dq);
+
#ifdef __cplusplus
}
#endif
diff --git a/lib/librte_rcu/rte_rcu_version.map
b/lib/librte_rcu/rte_rcu_version.map
index f8b9ef2ab..dfac88a37 100644
--- a/lib/librte_rcu/rte_rcu_version.map
+++ b/lib/librte_rcu/rte_rcu_version.map
@@ -8,6 +8,10 @@ EXPERIMENTAL {
rte_rcu_qsbr_synchronize;
rte_rcu_qsbr_thread_register;
rte_rcu_qsbr_thread_unregister;
+ rte_rcu_qsbr_dq_create;
+ rte_rcu_qsbr_dq_enqueue;
+ rte_rcu_qsbr_dq_reclaim;
+ rte_rcu_qsbr_dq_delete;
local: *;
};
diff --git a/lib/meson.build b/lib/meson.build
index 9c3cc55d5..15e91a303 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -11,7 +11,9 @@
libraries = [
'kvargs', # eal depends on kvargs
'eal', # everything depends on eal
- 'ring', 'mempool', 'mbuf', 'net', 'meter', 'ethdev', 'pci', # core
+ 'ring',
+ 'rcu', # rcu depends on ring
+ 'mempool', 'mbuf', 'net', 'meter', 'ethdev', 'pci', # core
'cmdline',
'metrics', # bitrate/latency stats depends on this
'hash', # efd depends on this
@@ -22,7 +24,7 @@ libraries = [
'gro', 'gso', 'ip_frag', 'jobstats',
'kni', 'latencystats', 'lpm', 'member',
'power', 'pdump', 'rawdev',
- 'rcu', 'rib', 'reorder', 'sched', 'security', 'stack', 'vhost',
+ 'rib', 'reorder', 'sched', 'security', 'stack', 'vhost',
# ipsec lib depends on net, crypto and security
'ipsec',
#fib lib depends on rib
--
2.17.1
