DPDK components and applications can have their say when a new lcore is
initialized. For this, they can register a callback for initializing and
releasing their private data.
Signed-off-by: David Marchand <david.march...@redhat.com>
---
Changes since v1:
- added unit test (since missing some coverage, for v3),
- preferred callback and removed mention of notification,
---
app/test/test_lcores.c | 95 ++++++++++++++++
lib/librte_eal/common/eal_common_lcore.c | 139 ++++++++++++++++++++++-
lib/librte_eal/common/eal_private.h | 3 +-
lib/librte_eal/include/rte_lcore.h | 68 +++++++++++
lib/librte_eal/rte_eal_version.map | 2 +
5 files changed, 301 insertions(+), 6 deletions(-)
diff --git a/app/test/test_lcores.c b/app/test/test_lcores.c
index 155b255b94..cf2439f71d 100644
--- a/app/test/test_lcores.c
+++ b/app/test/test_lcores.c
@@ -5,6 +5,7 @@
#include <pthread.h>
#include <string.h>
+#include <rte_common.h>
#include <rte_lcore.h>
#include "test.h"
@@ -113,6 +114,95 @@ test_non_eal_lcores(unsigned int eal_threads_count)
return ret;
}
+struct limit_lcore_context {
+ unsigned int init;
+ unsigned int max;
+ unsigned int uninit;
+};
+static int
+limit_lcores_init(unsigned int lcore_id __rte_unused, void *arg)
+{
+ struct limit_lcore_context *l = arg;
+
+ l->init++;
+ if (l->init > l->max)
+ return -1;
+ return 0;
+}
+static void
+limit_lcores_uninit(unsigned int lcore_id __rte_unused, void *arg)
+{
+ struct limit_lcore_context *l = arg;
+
+ l->uninit++;
+}
+
+static int
+test_lcores_callback(unsigned int eal_threads_count)
+{
+ struct limit_lcore_context l;
+ void *handle;
+
+ /* Refuse last lcore => callback register error. */
+ memset(&l, 0, sizeof(l));
+ l.max = eal_threads_count - 1;
+ handle = rte_lcore_callback_register("limit", limit_lcores_init,
+ limit_lcores_uninit, &l);
+ if (handle != NULL) {
+ printf("lcore callback register should have failed\n");
+ goto error;
+ }
+ /* Refusal happens at the n th call to the init callback.
+ * Besides, n - 1 were accepted, so we expect as many uninit calls when
+ * the rollback happens.
+ */
+ if (l.init != eal_threads_count) {
+ printf("lcore init calls failed: expected %u, got %u\n",
+ eal_threads_count, l.init);
+ goto error;
+ }
+ if (l.uninit != eal_threads_count - 1) {
+ printf("lcore uninit calls failed: expected %u, got %u\n",
+ eal_threads_count - 1, l.uninit);
+ goto error;
+ }
+
+ /* Accept all lcore and unregister. */
+ memset(&l, 0, sizeof(l));
+ l.max = eal_threads_count;
+ handle = rte_lcore_callback_register("limit", limit_lcores_init,
+ limit_lcores_uninit, &l);
+ if (handle == NULL) {
+ printf("lcore callback register failed\n");
+ goto error;
+ }
+ if (l.uninit != 0) {
+ printf("lcore uninit got called %u times during register\n",
+ l.uninit);
+ goto error;
+ }
+ rte_lcore_callback_unregister(handle);
+ handle = NULL;
+ if (l.init != eal_threads_count) {
+ printf("lcore init got called %u times during unregister
(expected %u)\n",
+ l.init, eal_threads_count);
+ goto error;
+ }
+ if (l.uninit != eal_threads_count) {
+ printf("lcore uninit calls failed: expected %u, got %u\n",
+ eal_threads_count, l.uninit);
+ goto error;
+ }
+
+ return 0;
+
+error:
+ if (handle != NULL)
+ rte_lcore_callback_unregister(handle);
+
+ return -1;
+}
+
static int
test_lcores(void)
{
@@ -133,6 +223,11 @@ test_lcores(void)
if (test_non_eal_lcores(eal_threads_count) < 0)
return TEST_FAILED;
+ if (test_lcores_callback(eal_threads_count) < 0)
+ return TEST_FAILED;
+
+ /* FIXME: missing a test on callback + registering non-EAL threads */
+
return TEST_SUCCESS;
}
diff --git a/lib/librte_eal/common/eal_common_lcore.c
b/lib/librte_eal/common/eal_common_lcore.c
index 7db05428e7..5140026b6c 100644
--- a/lib/librte_eal/common/eal_common_lcore.c
+++ b/lib/librte_eal/common/eal_common_lcore.c
@@ -223,11 +223,114 @@ rte_socket_id_by_idx(unsigned int idx)
}
static rte_spinlock_t lcore_lock = RTE_SPINLOCK_INITIALIZER;
+struct lcore_callback {
+ TAILQ_ENTRY(lcore_callback) next;
+ char *name;
+ rte_lcore_init_cb init;
+ rte_lcore_uninit_cb uninit;
+ void *arg;
+};
+static TAILQ_HEAD(lcore_callbacks_head, lcore_callback) lcore_callbacks =
+ TAILQ_HEAD_INITIALIZER(lcore_callbacks);
+
+static int
+callback_init(struct lcore_callback *callback, unsigned int lcore_id)
+{
+ if (callback->init == NULL)
+ return 0;
+ RTE_LOG(DEBUG, EAL, "Call init for lcore callback %s, lcore_id %u\n",
+ callback->name, lcore_id);
+ return callback->init(lcore_id, callback->arg);
+}
+
+static void
+callback_uninit(struct lcore_callback *callback, unsigned int lcore_id)
+{
+ if (callback->uninit == NULL)
+ return;
+ RTE_LOG(DEBUG, EAL, "Call uninit for lcore callback %s, lcore_id %u\n",
+ callback->name, lcore_id);
+ callback->uninit(lcore_id, callback->arg);
+}
+
+void *
+rte_lcore_callback_register(const char *name, rte_lcore_init_cb init,
+ rte_lcore_uninit_cb uninit, void *arg)
+{
+ struct rte_config *cfg = rte_eal_get_configuration();
+ struct lcore_callback *callback;
+ unsigned int lcore_id;
+
+ callback = calloc(1, sizeof(*callback));
+ if (callback == NULL)
+ return NULL;
+ if (asprintf(&callback->name, "%s-%p", name, arg) == -1) {
+ free(callback);
+ return NULL;
+ }
+ callback->init = init;
+ callback->uninit = uninit;
+ callback->arg = arg;
+ rte_spinlock_lock(&lcore_lock);
+ if (callback->init == NULL)
+ goto no_init;
+ for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
+ if (cfg->lcore_role[lcore_id] == ROLE_OFF)
+ continue;
+ if (callback_init(callback, lcore_id) == 0)
+ continue;
+ /* Callback refused init for this lcore, uninitialize all
+ * previous lcore.
+ */
+ for (; lcore_id != 0; lcore_id--) {
+ if (cfg->lcore_role[lcore_id - 1] == ROLE_OFF)
+ continue;
+ callback_uninit(callback, lcore_id - 1);
+ }
+ free(callback);
+ callback = NULL;
+ goto out;
+ }
+no_init:
+ TAILQ_INSERT_TAIL(&lcore_callbacks, callback, next);
+ RTE_LOG(DEBUG, EAL, "Registered new lcore callback %s (%sinit,
%suninit).\n",
+ callback->name, callback->init == NULL ? "NO " : "",
+ callback->uninit == NULL ? "NO " : "");
+out:
+ rte_spinlock_unlock(&lcore_lock);
+ return callback;
+}
+
+void
+rte_lcore_callback_unregister(void *handle)
+{
+ struct rte_config *cfg = rte_eal_get_configuration();
+ struct lcore_callback *callback = handle;
+ unsigned int lcore_id;
+
+ rte_spinlock_lock(&lcore_lock);
+ if (callback->uninit == NULL)
+ goto no_uninit;
+ for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
+ if (cfg->lcore_role[lcore_id] == ROLE_OFF)
+ continue;
+ callback_uninit(callback, lcore_id);
+ }
+no_uninit:
+ TAILQ_REMOVE(&lcore_callbacks, callback, next);
+ rte_spinlock_unlock(&lcore_lock);
+ RTE_LOG(DEBUG, EAL, "Unregistered lcore callback %s-%p.\n",
+ callback->name, callback->arg);
+ free(callback->name);
+ free(callback);
+}
unsigned int
eal_lcore_non_eal_allocate(void)
{
struct rte_config *cfg = rte_eal_get_configuration();
+ struct lcore_callback *callback;
+ struct lcore_callback *prev;
unsigned int lcore_id;
rte_spinlock_lock(&lcore_lock);
@@ -238,8 +341,30 @@ eal_lcore_non_eal_allocate(void)
cfg->lcore_count++;
break;
}
- if (lcore_id == RTE_MAX_LCORE)
+ if (lcore_id == RTE_MAX_LCORE) {
RTE_LOG(DEBUG, EAL, "No lcore available.\n");
+ goto out;
+ }
+ TAILQ_FOREACH(callback, &lcore_callbacks, next) {
+ if (callback_init(callback, lcore_id) == 0)
+ continue;
+ /* Callback refused init for this lcore, call uninit for all
+ * previous callbacks.
+ */
+ prev = TAILQ_PREV(callback, lcore_callbacks_head, next);
+ while (prev != NULL) {
+ callback_uninit(prev, lcore_id);
+ prev = TAILQ_PREV(callback, lcore_callbacks_head,
+ next);
+ }
+ RTE_LOG(DEBUG, EAL, "Initialization refused for lcore %u.\n",
+ lcore_id);
+ cfg->lcore_role[lcore_id] = ROLE_OFF;
+ cfg->lcore_count--;
+ lcore_id = RTE_MAX_LCORE;
+ goto out;
+ }
+out:
rte_spinlock_unlock(&lcore_lock);
return lcore_id;
}
@@ -248,11 +373,15 @@ void
eal_lcore_non_eal_release(unsigned int lcore_id)
{
struct rte_config *cfg = rte_eal_get_configuration();
+ struct lcore_callback *callback;
rte_spinlock_lock(&lcore_lock);
- if (cfg->lcore_role[lcore_id] == ROLE_NON_EAL) {
- cfg->lcore_role[lcore_id] = ROLE_OFF;
- cfg->lcore_count--;
- }
+ if (cfg->lcore_role[lcore_id] != ROLE_NON_EAL)
+ goto out;
+ TAILQ_FOREACH(callback, &lcore_callbacks, next)
+ callback_uninit(callback, lcore_id);
+ cfg->lcore_role[lcore_id] = ROLE_OFF;
+ cfg->lcore_count--;
+out:
rte_spinlock_unlock(&lcore_lock);
}
diff --git a/lib/librte_eal/common/eal_private.h
b/lib/librte_eal/common/eal_private.h
index 73238ff157..fc79564111 100644
--- a/lib/librte_eal/common/eal_private.h
+++ b/lib/librte_eal/common/eal_private.h
@@ -401,7 +401,8 @@ uint64_t get_tsc_freq_arch(void);
*
* @return
* - the id of a lcore with role ROLE_NON_EAL on success.
- * - RTE_MAX_LCORE if none was available.
+ * - RTE_MAX_LCORE if none was available or initializing was refused (see
+ * rte_lcore_callback_register).
*/
unsigned int eal_lcore_non_eal_allocate(void);
diff --git a/lib/librte_eal/include/rte_lcore.h
b/lib/librte_eal/include/rte_lcore.h
index ea86220394..27b29a1f87 100644
--- a/lib/librte_eal/include/rte_lcore.h
+++ b/lib/librte_eal/include/rte_lcore.h
@@ -229,6 +229,74 @@ unsigned int rte_get_next_lcore(unsigned int i, int
skip_master, int wrap);
i<RTE_MAX_LCORE; \
i = rte_get_next_lcore(i, 1, 0))
+/**
+ * Callback prototype for initializing lcores.
+ *
+ * @param lcore_id
+ * The lcore to consider.
+ * @param arg
+ * An opaque pointer passed at callback registration.
+ * @return
+ * - -1 when refusing this operation,
+ * - 0 otherwise.
+ */
+typedef int (*rte_lcore_init_cb)(unsigned int lcore_id, void *arg);
+
+/**
+ * Callback prototype for uninitializing lcores.
+ *
+ * @param lcore_id
+ * The lcore to consider.
+ * @param arg
+ * An opaque pointer passed at callback registration.
+ */
+typedef void (*rte_lcore_uninit_cb)(unsigned int lcore_id, void *arg);
+
+/**
+ * Register callbacks invoked when initializing and uninitializing a lcore.
+ *
+ * This function calls the init callback with all initialized lcores.
+ * Any error reported by the init callback triggers a rollback calling the
+ * uninit callback for each lcore.
+ * If this step succeeds, the callbacks are put in the lcore callbacks list
+ * that will get called for each lcore allocation/release.
+ *
+ * Note: callbacks execution is serialised under a lock protecting the lcores
+ * and callbacks list.
+ *
+ * @param name
+ * A name serving as a small description for this callback.
+ * @param init
+ * The callback invoked when a lcore_id is initialized.
+ * @param uninit
+ * The callback invoked when a lcore_id is uninitialized.
+ * @param arg
+ * An optional argument that gets passed to the callback when it gets
+ * invoked.
+ * @return
+ * On success, returns an opaque pointer for the registered object.
+ * On failure (either memory allocation issue in the function itself or an
+ * error is returned by the init callback itself), returns NULL.
+ */
+__rte_experimental
+void *
+rte_lcore_callback_register(const char *name, rte_lcore_init_cb init,
+ rte_lcore_uninit_cb uninit, void *arg);
+
+/**
+ * Unregister callbacks previously registered with rte_lcore_callback_register.
+ *
+ * This function calls the uninit callback with all initialized lcores.
+ * The callbacks are then removed from the lcore callbacks list.
+ *
+ * @param handle
+ * The handle pointer returned by a former successful call to
+ * rte_lcore_callback_register.
+ */
+__rte_experimental
+void
+rte_lcore_callback_unregister(void *handle);
+
/**
* Set core affinity of the current thread.
* Support both EAL and non-EAL thread and update TLS.
diff --git a/lib/librte_eal/rte_eal_version.map
b/lib/librte_eal/rte_eal_version.map
index 5503dd7620..c3e762c1d9 100644
--- a/lib/librte_eal/rte_eal_version.map
+++ b/lib/librte_eal/rte_eal_version.map
@@ -395,6 +395,8 @@ EXPERIMENTAL {
rte_trace_save;
# added in 20.08
+ rte_lcore_callback_register;
+ rte_lcore_callback_unregister;
rte_thread_register;
rte_thread_unregister;
};
--
2.23.0
