[dpdk-dev] [PATCH v3 66/68] eal: add memory validator callback

Anatoly Burakov anatoly.burakov at intel.com
Wed Apr 4 01:22:18 CEST 2018


This API will enable application to register for notifications
on page allocations that are about to happen, giving the application
a chance to allow or deny the allocation when total memory utilization
as a result would be above specified limit on specified socket.

Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>
---
 lib/librte_eal/common/eal_common_memalloc.c | 138 +++++++++++++++++++++++++++-
 lib/librte_eal/common/eal_common_memory.c   |  26 ++++++
 lib/librte_eal/common/eal_memalloc.h        |  10 ++
 lib/librte_eal/common/include/rte_memory.h  |  59 ++++++++++++
 lib/librte_eal/rte_eal_version.map          |   2 +
 5 files changed, 234 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/common/eal_common_memalloc.c b/lib/librte_eal/common/eal_common_memalloc.c
index 2d2d46f..49fd53c 100644
--- a/lib/librte_eal/common/eal_common_memalloc.c
+++ b/lib/librte_eal/common/eal_common_memalloc.c
@@ -22,14 +22,26 @@ struct mem_event_callback_entry {
 	rte_mem_event_callback_t clb;
 };
 
+struct mem_alloc_validator_entry {
+	TAILQ_ENTRY(mem_alloc_validator_entry) next;
+	char name[RTE_MEM_ALLOC_VALIDATOR_NAME_LEN];
+	rte_mem_alloc_validator_t clb;
+	int socket_id;
+	size_t limit;
+};
+
 /** Double linked list of actions. */
 TAILQ_HEAD(mem_event_callback_entry_list, mem_event_callback_entry);
+TAILQ_HEAD(mem_alloc_validator_entry_list, mem_alloc_validator_entry);
 
 static struct mem_event_callback_entry_list mem_event_callback_list =
 	TAILQ_HEAD_INITIALIZER(mem_event_callback_list);
-
 static rte_rwlock_t mem_event_rwlock = RTE_RWLOCK_INITIALIZER;
 
+static struct mem_alloc_validator_entry_list mem_alloc_validator_list =
+	TAILQ_HEAD_INITIALIZER(mem_alloc_validator_list);
+static rte_rwlock_t mem_alloc_validator_rwlock = RTE_RWLOCK_INITIALIZER;
+
 static struct mem_event_callback_entry *
 find_mem_event_callback(const char *name)
 {
@@ -42,6 +54,18 @@ find_mem_event_callback(const char *name)
 	return r;
 }
 
+static struct mem_alloc_validator_entry *
+find_mem_alloc_validator(const char *name, int socket_id)
+{
+	struct mem_alloc_validator_entry *r;
+
+	TAILQ_FOREACH(r, &mem_alloc_validator_list, next) {
+		if (!strcmp(r->name, name) && r->socket_id == socket_id)
+			break;
+	}
+	return r;
+}
+
 bool
 eal_memalloc_is_contig(const struct rte_memseg_list *msl, void *start,
 		size_t len)
@@ -221,3 +245,115 @@ eal_memalloc_mem_event_notify(enum rte_mem_event event, const void *start,
 
 	rte_rwlock_read_unlock(&mem_event_rwlock);
 }
+
+int
+eal_memalloc_mem_alloc_validator_register(const char *name,
+		rte_mem_alloc_validator_t clb, int socket_id, size_t limit)
+{
+	struct mem_alloc_validator_entry *entry;
+	int ret, len;
+	if (name == NULL || clb == NULL || socket_id < 0) {
+		rte_errno = EINVAL;
+		return -1;
+	}
+	len = strnlen(name, RTE_MEM_ALLOC_VALIDATOR_NAME_LEN);
+	if (len == 0) {
+		rte_errno = EINVAL;
+		return -1;
+	} else if (len == RTE_MEM_ALLOC_VALIDATOR_NAME_LEN) {
+		rte_errno = ENAMETOOLONG;
+		return -1;
+	}
+	rte_rwlock_write_lock(&mem_alloc_validator_rwlock);
+
+	entry = find_mem_alloc_validator(name, socket_id);
+	if (entry != NULL) {
+		rte_errno = EEXIST;
+		ret = -1;
+		goto unlock;
+	}
+
+	entry = malloc(sizeof(*entry));
+	if (entry == NULL) {
+		rte_errno = ENOMEM;
+		ret = -1;
+		goto unlock;
+	}
+
+	/* callback successfully created and is valid, add it to the list */
+	entry->clb = clb;
+	entry->socket_id = socket_id;
+	entry->limit = limit;
+	snprintf(entry->name, RTE_MEM_ALLOC_VALIDATOR_NAME_LEN, "%s", name);
+	TAILQ_INSERT_TAIL(&mem_alloc_validator_list, entry, next);
+
+	ret = 0;
+
+	RTE_LOG(DEBUG, EAL, "Mem alloc validator '%s' on socket %i with limit %zu registered\n",
+		name, socket_id, limit);
+
+unlock:
+	rte_rwlock_write_unlock(&mem_alloc_validator_rwlock);
+	return ret;
+}
+
+int
+eal_memalloc_mem_alloc_validator_unregister(const char *name, int socket_id)
+{
+	struct mem_alloc_validator_entry *entry;
+	int ret, len;
+
+	if (name == NULL || socket_id < 0) {
+		rte_errno = EINVAL;
+		return -1;
+	}
+	len = strnlen(name, RTE_MEM_ALLOC_VALIDATOR_NAME_LEN);
+	if (len == 0) {
+		rte_errno = EINVAL;
+		return -1;
+	} else if (len == RTE_MEM_ALLOC_VALIDATOR_NAME_LEN) {
+		rte_errno = ENAMETOOLONG;
+		return -1;
+	}
+	rte_rwlock_write_lock(&mem_alloc_validator_rwlock);
+
+	entry = find_mem_alloc_validator(name, socket_id);
+	if (entry == NULL) {
+		rte_errno = ENOENT;
+		ret = -1;
+		goto unlock;
+	}
+	TAILQ_REMOVE(&mem_alloc_validator_list, entry, next);
+	free(entry);
+
+	ret = 0;
+
+	RTE_LOG(DEBUG, EAL, "Mem alloc validator '%s' on socket %i unregistered\n",
+		name, socket_id);
+
+unlock:
+	rte_rwlock_write_unlock(&mem_alloc_validator_rwlock);
+	return ret;
+}
+
+int
+eal_memalloc_mem_alloc_validate(int socket_id, size_t new_len)
+{
+	struct mem_alloc_validator_entry *entry;
+	int ret = 0;
+
+	rte_rwlock_read_lock(&mem_alloc_validator_rwlock);
+
+	TAILQ_FOREACH(entry, &mem_alloc_validator_list, next) {
+		if (entry->socket_id != socket_id || entry->limit > new_len)
+			continue;
+		RTE_LOG(DEBUG, EAL, "Calling mem alloc validator '%s' on socket %i\n",
+			entry->name, entry->socket_id);
+		if (entry->clb(socket_id, entry->limit, new_len) < 0)
+			ret = -1;
+	}
+
+	rte_rwlock_read_unlock(&mem_alloc_validator_rwlock);
+
+	return ret;
+}
diff --git a/lib/librte_eal/common/eal_common_memory.c b/lib/librte_eal/common/eal_common_memory.c
index e3ce69c..d221240 100644
--- a/lib/librte_eal/common/eal_common_memory.c
+++ b/lib/librte_eal/common/eal_common_memory.c
@@ -632,6 +632,32 @@ rte_mem_event_callback_unregister(const char *name)
 	return eal_memalloc_mem_event_callback_unregister(name);
 }
 
+int __rte_experimental
+rte_mem_alloc_validator_register(const char *name,
+		rte_mem_alloc_validator_t clb, int socket_id, size_t limit)
+{
+	/* FreeBSD boots with legacy mem enabled by default */
+	if (internal_config.legacy_mem) {
+		RTE_LOG(DEBUG, EAL, "Registering mem alloc validators not supported\n");
+		rte_errno = ENOTSUP;
+		return -1;
+	}
+	return eal_memalloc_mem_alloc_validator_register(name, clb, socket_id,
+			limit);
+}
+
+int __rte_experimental
+rte_mem_alloc_validator_unregister(const char *name, int socket_id)
+{
+	/* FreeBSD boots with legacy mem enabled by default */
+	if (internal_config.legacy_mem) {
+		RTE_LOG(DEBUG, EAL, "Registering mem alloc validators not supported\n");
+		rte_errno = ENOTSUP;
+		return -1;
+	}
+	return eal_memalloc_mem_alloc_validator_unregister(name, socket_id);
+}
+
 /* Dump the physical memory layout on console */
 void
 rte_dump_physmem_layout(FILE *f)
diff --git a/lib/librte_eal/common/eal_memalloc.h b/lib/librte_eal/common/eal_memalloc.h
index 4d27403..6bec52c 100644
--- a/lib/librte_eal/common/eal_memalloc.h
+++ b/lib/librte_eal/common/eal_memalloc.h
@@ -67,4 +67,14 @@ void
 eal_memalloc_mem_event_notify(enum rte_mem_event event, const void *start,
 		size_t len);
 
+int
+eal_memalloc_mem_alloc_validator_register(const char *name,
+		rte_mem_alloc_validator_t clb, int socket_id, size_t limit);
+
+int
+eal_memalloc_mem_alloc_validator_unregister(const char *name, int socket_id);
+
+int
+eal_memalloc_mem_alloc_validate(int socket_id, size_t new_len);
+
 #endif // EAL_MEMALLOC_H
diff --git a/lib/librte_eal/common/include/rte_memory.h b/lib/librte_eal/common/include/rte_memory.h
index 0de1198..0318bfe 100644
--- a/lib/librte_eal/common/include/rte_memory.h
+++ b/lib/librte_eal/common/include/rte_memory.h
@@ -339,6 +339,65 @@ rte_mem_event_callback_register(const char *name, rte_mem_event_callback_t clb);
 int __rte_experimental
 rte_mem_event_callback_unregister(const char *name);
 
+
+#define RTE_MEM_ALLOC_VALIDATOR_NAME_LEN 64
+/**< maximum length of alloc validator name */
+/**
+ * Function typedef used to register memory allocation validation callbacks.
+ *
+ * Returning 0 will allow allocation attempt to continue. Returning -1 will
+ * prevent allocation from succeeding.
+ */
+typedef int (*rte_mem_alloc_validator_t)(int socket_id,
+		size_t cur_limit, size_t new_len);
+
+/**
+ * @brief Register validator callback for memory allocations.
+ *
+ * Callbacks registered by this function will be called right before memory
+ * allocator is about to trigger allocation of more pages from the system if
+ * said allocation will bring total memory usage above specified limit on
+ * specified socket. User will be able to cancel pending allocation if callback
+ * returns -1.
+ *
+ * @param name
+ *   Name associated with specified callback to be added to the list.
+ *
+ * @param clb
+ *   Callback function pointer.
+ *
+ * @param socket_id
+ *   Socket ID on which to watch for allocations.
+ *
+ * @param limit
+ *   Limit above which to trigger callbacks.
+ *
+ * @return
+ *   0 on successful callback register
+ *   -1 on unsuccessful callback register, with rte_errno value indicating
+ *   reason for failure.
+ */
+int __rte_experimental
+rte_mem_alloc_validator_register(const char *name,
+		rte_mem_alloc_validator_t clb, int socket_id, size_t limit);
+
+/**
+ * @brief Unregister validator callback for memory allocations.
+ *
+ * @param name
+ *   Name associated with specified callback to be removed from the list.
+ *
+ * @param socket_id
+ *   Socket ID on which to watch for allocations.
+ *
+ * @return
+ *   0 on successful callback unregister
+ *   -1 on unsuccessful callback unregister, with rte_errno value indicating
+ *   reason for failure.
+ */
+int __rte_experimental
+rte_mem_alloc_validator_unregister(const char *name, int socket_id);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/librte_eal/rte_eal_version.map b/lib/librte_eal/rte_eal_version.map
index 0460edb..b94c48c 100644
--- a/lib/librte_eal/rte_eal_version.map
+++ b/lib/librte_eal/rte_eal_version.map
@@ -238,6 +238,8 @@ EXPERIMENTAL {
 	rte_fbarray_set_used;
 	rte_log_register_type_and_pick_level;
 	rte_malloc_dump_heaps;
+	rte_mem_alloc_validator_register;
+	rte_mem_alloc_validator_unregister;
 	rte_mem_event_callback_register;
 	rte_mem_event_callback_unregister;
 	rte_mem_iova2virt;
-- 
2.7.4


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