eal: add lcore init callbacks
authorDavid Marchand <david.marchand@redhat.com>
Mon, 6 Jul 2020 20:52:31 +0000 (22:52 +0200)
committerDavid Marchand <david.marchand@redhat.com>
Wed, 8 Jul 2020 12:41:06 +0000 (14:41 +0200)
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.marchand@redhat.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
app/test/test_lcores.c
lib/librte_eal/common/eal_common_lcore.c
lib/librte_eal/common/eal_private.h
lib/librte_eal/include/rte_lcore.h
lib/librte_eal/rte_eal_version.map

index afb9cdd..7df827b 100644 (file)
@@ -5,6 +5,7 @@
 #include <pthread.h>
 #include <string.h>
 
+#include <rte_common.h>
 #include <rte_errno.h>
 #include <rte_lcore.h>
 
@@ -117,6 +118,226 @@ skip_lcore_any:
        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("Error: 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("Error: lcore callback register failed but incorrect init calls, expected %u, got %u\n",
+                       eal_threads_count, l.init);
+               goto error;
+       }
+       if (l.uninit != eal_threads_count - 1) {
+               printf("Error: lcore callback register failed but incorrect uninit calls, 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("Error: lcore callback register failed\n");
+               goto error;
+       }
+       if (l.uninit != 0) {
+               printf("Error: lcore callback register succeeded but incorrect uninit calls, expected 0, got %u\n",
+                       l.uninit);
+               goto error;
+       }
+       rte_lcore_callback_unregister(handle);
+       handle = NULL;
+       if (l.init != eal_threads_count) {
+               printf("Error: lcore callback unregister done but incorrect init calls, expected %u, got %u\n",
+                       eal_threads_count, l.init);
+               goto error;
+       }
+       if (l.uninit != eal_threads_count) {
+               printf("Error: lcore callback unregister done but incorrect uninit calls, 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_non_eal_lcores_callback(unsigned int eal_threads_count)
+{
+       struct thread_context thread_contexts[2];
+       unsigned int non_eal_threads_count = 0;
+       struct limit_lcore_context l[2] = {};
+       unsigned int registered_count = 0;
+       struct thread_context *t;
+       void *handle[2] = {};
+       unsigned int i;
+       int ret;
+
+       /* This test requires two empty slots to be sure lcore init refusal is
+        * because of callback execution.
+        */
+       if (eal_threads_count + 2 >= RTE_MAX_LCORE)
+               return 0;
+
+       /* Register two callbacks:
+        * - first one accepts any lcore,
+        * - second one accepts all EAL lcore + one more for the first non-EAL
+        *   thread, then refuses the next lcore.
+        */
+       l[0].max = UINT_MAX;
+       handle[0] = rte_lcore_callback_register("no_limit", limit_lcores_init,
+               limit_lcores_uninit, &l[0]);
+       if (handle[0] == NULL) {
+               printf("Error: lcore callback [0] register failed\n");
+               goto error;
+       }
+       l[1].max = eal_threads_count + 1;
+       handle[1] = rte_lcore_callback_register("limit", limit_lcores_init,
+               limit_lcores_uninit, &l[1]);
+       if (handle[1] == NULL) {
+               printf("Error: lcore callback [1] register failed\n");
+               goto error;
+       }
+       if (l[0].init != eal_threads_count || l[1].init != eal_threads_count) {
+               printf("Error: lcore callbacks register succeeded but incorrect init calls, expected %u, %u, got %u, %u\n",
+                       eal_threads_count, eal_threads_count,
+                       l[0].init, l[1].init);
+               goto error;
+       }
+       if (l[0].uninit != 0 || l[1].uninit != 0) {
+               printf("Error: lcore callbacks register succeeded but incorrect uninit calls, expected 0, 1, got %u, %u\n",
+                       l[0].uninit, l[1].uninit);
+               goto error;
+       }
+       /* First thread that expects a valid lcore id. */
+       t = &thread_contexts[0];
+       t->state = INIT;
+       t->registered_count = &registered_count;
+       t->lcore_id_any = false;
+       if (pthread_create(&t->id, NULL, thread_loop, t) != 0)
+               goto cleanup_threads;
+       non_eal_threads_count++;
+       while (__atomic_load_n(&registered_count, __ATOMIC_ACQUIRE) !=
+                       non_eal_threads_count)
+               ;
+       if (l[0].init != eal_threads_count + 1 ||
+                       l[1].init != eal_threads_count + 1) {
+               printf("Error: incorrect init calls, expected %u, %u, got %u, %u\n",
+                       eal_threads_count + 1, eal_threads_count + 1,
+                       l[0].init, l[1].init);
+               goto cleanup_threads;
+       }
+       if (l[0].uninit != 0 || l[1].uninit != 0) {
+               printf("Error: incorrect uninit calls, expected 0, 0, got %u, %u\n",
+                       l[0].uninit, l[1].uninit);
+               goto cleanup_threads;
+       }
+       /* Second thread, that expects LCORE_ID_ANY because of init refusal. */
+       t = &thread_contexts[1];
+       t->state = INIT;
+       t->registered_count = &registered_count;
+       t->lcore_id_any = true;
+       if (pthread_create(&t->id, NULL, thread_loop, t) != 0)
+               goto cleanup_threads;
+       non_eal_threads_count++;
+       while (__atomic_load_n(&registered_count, __ATOMIC_ACQUIRE) !=
+                       non_eal_threads_count)
+               ;
+       if (l[0].init != eal_threads_count + 2 ||
+                       l[1].init != eal_threads_count + 2) {
+               printf("Error: incorrect init calls, expected %u, %u, got %u, %u\n",
+                       eal_threads_count + 2, eal_threads_count + 2,
+                       l[0].init, l[1].init);
+               goto cleanup_threads;
+       }
+       if (l[0].uninit != 1 || l[1].uninit != 0) {
+               printf("Error: incorrect uninit calls, expected 1, 0, got %u, %u\n",
+                       l[0].uninit, l[1].uninit);
+               goto cleanup_threads;
+       }
+       /* Release all threads, and check their states. */
+       __atomic_store_n(&registered_count, 0, __ATOMIC_RELEASE);
+       ret = 0;
+       for (i = 0; i < non_eal_threads_count; i++) {
+               t = &thread_contexts[i];
+               pthread_join(t->id, NULL);
+               if (t->state != DONE)
+                       ret = -1;
+       }
+       if (ret < 0)
+               goto error;
+       if (l[0].uninit != 2 || l[1].uninit != 1) {
+               printf("Error: threads reported having successfully registered and unregistered, but incorrect uninit calls, expected 2, 1, got %u, %u\n",
+                       l[0].uninit, l[1].uninit);
+               goto error;
+       }
+       rte_lcore_callback_unregister(handle[0]);
+       rte_lcore_callback_unregister(handle[1]);
+       return 0;
+
+cleanup_threads:
+       /* Release all threads */
+       __atomic_store_n(&registered_count, 0, __ATOMIC_RELEASE);
+       for (i = 0; i < non_eal_threads_count; i++) {
+               t = &thread_contexts[i];
+               pthread_join(t->id, NULL);
+       }
+error:
+       if (handle[1] != NULL)
+               rte_lcore_callback_unregister(handle[1]);
+       if (handle[0] != NULL)
+               rte_lcore_callback_unregister(handle[0]);
+       return -1;
+}
+
 static int
 test_lcores(void)
 {
@@ -137,6 +358,12 @@ 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;
+
+       if (test_non_eal_lcores_callback(eal_threads_count) < 0)
+               return TEST_FAILED;
+
        return TEST_SUCCESS;
 }
 
index 679cfe3..c719070 100644 (file)
@@ -232,11 +232,124 @@ 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);
+}
+
+static void
+free_callback(struct lcore_callback *callback)
+{
+       free(callback->name);
+       free(callback);
+}
+
+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;
+
+       if (name == NULL)
+               return NULL;
+       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.
+                */
+               while (lcore_id-- != 0) {
+                       if (cfg->lcore_role[lcore_id] == ROLE_OFF)
+                               continue;
+                       callback_uninit(callback, lcore_id);
+               }
+               free_callback(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;
+
+       if (callback == NULL)
+               return;
+       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(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);
@@ -247,8 +360,29 @@ 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(prev, 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;
 }
@@ -257,11 +391,15 @@ 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);
 }
index ef0c3df..7a89f2d 100644 (file)
@@ -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);
 
index 2fd1a03..6e7206c 100644 (file)
@@ -229,6 +229,76 @@ 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.
+ *   init can be NULL.
+ * @param uninit
+ *   The callback invoked when a lcore_id is uninitialized.
+ *   uninit can be NULL.
+ * @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.
index 5cd5f8b..41f3950 100644 (file)
@@ -396,6 +396,8 @@ EXPERIMENTAL {
 
        # added in 20.08
        rte_eal_vfio_get_vf_token;
+       rte_lcore_callback_register;
+       rte_lcore_callback_unregister;
        rte_thread_register;
        rte_thread_unregister;
 };