prov/util: Define monitor unsubscribe_on_delete

Not all memory montiors have a 1-N relationship between subscribe and
the MR cache entries. Some memory monitors, such as kdreg2, have a 1-1
relationship and require unsubscribe to be called when the corresponding
MR cache entry is deleted.

To meet this requirement, unsubscribe_on_delete is defined. When true
for a memory monitor, ofi_monitor_unsubscribe() will be called on MR
cache being freed.

Signed-off-by: Mike Uttormark <[email protected]>
Signed-off-by: Ian Ziemba <[email protected]>

include/ofi_mr.h

@@ -192,6 +192,17 @@ struct ofi_mem_monitor {
 	bool (*valid)(struct ofi_mem_monitor *notifier,
 		      const struct ofi_mr_info *info, struct ofi_mr_entry *entry);
 	const char *name;
+
+	/* Set this to true if the monitor tracks each individual memory
+	 * registration.  That is, the monitor has a 1-to-1 mapping to MR Cache
+	 * entry and corresponding subscribe.
+	 *
+	 * When true, the MR Cache will call the memory monitor unsubscribe()
+	 * method when deleting an MR Cache entry.  This allows the monitor
+	 * stop tracking memory regions for which there are no longer
+	 * registrations.
+	 */
+	bool unsubscribe_on_delete;
 };
 
 void ofi_monitor_init(struct ofi_mem_monitor *monitor);

prov/util/src/cuda_ipc_monitor.c

@@ -64,6 +64,7 @@ static struct ofi_mem_monitor cuda_ipc_monitor_ = {
 	.unsubscribe = ofi_monitor_unsubscribe_no_op,
 	.valid = cuda_ipc_monitor_valid,
 	.name = "cuda_ipc",
+	.unsubscribe_on_delete = false,
 };
 
 struct ofi_mem_monitor *cuda_ipc_monitor = &cuda_ipc_monitor_;

prov/util/src/cuda_mem_monitor.c

@@ -154,6 +154,7 @@ static struct ofi_mem_monitor cuda_mm = {
 	.unsubscribe = cuda_mm_unsubscribe,
 	.valid = cuda_mm_valid,
 	.name = "cuda",
+	.unsubscribe_on_delete = false,
 };
 
 struct ofi_mem_monitor *cuda_monitor = &cuda_mm;

prov/util/src/import_mem_monitor.c

@@ -70,6 +70,7 @@ static struct ofi_import_monitor impmon = {
 	.monitor.unsubscribe = ofi_import_monitor_unsubscribe,
 	.monitor.valid = ofi_import_monitor_valid,
 	.monitor.name = "import",
+	.monitor.unsubscribe_on_delete = false,
 };
 
 struct ofi_mem_monitor *import_monitor = &impmon.monitor;

prov/util/src/kdreg2_mem_monitor.c

@@ -39,6 +39,8 @@
 #define EVICTOR_THREAD_ATTR NULL
 #define INFINITE_TIMEOUT -1
 
+/* kdreg2 monitors each address range (byte accurate) with a unique cookie */
+
 static int kdreg2_monitor_subscribe(struct ofi_mem_monitor *monitor,
 				    const void *addr, size_t len,
 				    union ofi_mr_hmem_info *hmem_info)
@@ -63,6 +65,8 @@ static int kdreg2_monitor_subscribe(struct ofi_mem_monitor *monitor,
 	return 0;
 }
 
+/* Unsubscribe is via cookie, not address range */
+
 static void kdreg2_monitor_unsubscribe(struct ofi_mem_monitor *monitor,
 				       const void *addr, size_t len,
 				       union ofi_mr_hmem_info *hmem_info)
@@ -359,6 +363,7 @@ static struct ofi_kdreg2 kdreg2_mm = {
 	.monitor.unsubscribe = kdreg2_monitor_unsubscribe,
 	.monitor.valid       = kdreg2_monitor_valid,
 	.monitor.name        = "kdreg2",
+	.monitor.unsubscribe_on_delete = true,
 	.fd                  = -1,
 	.exit_pipe           = { -1, -1 },
 	.status_data         = NULL,

prov/util/src/rocr_ipc_monitor.c

@@ -65,6 +65,7 @@ static struct ofi_mem_monitor rocr_ipc_monitor_ = {
 	.unsubscribe = ofi_monitor_unsubscribe_no_op,
 	.valid = rocr_ipc_monitor_valid,
 	.name = "rocr_ipc",
+	.unsubscribe_on_delete = false,
 };
 
 struct ofi_mem_monitor *rocr_ipc_monitor = &rocr_ipc_monitor_;

prov/util/src/rocr_mem_monitor.c

@@ -73,6 +73,7 @@ static struct rocr_mm rocr_mm = {
 		.unsubscribe = rocr_mm_unsubscribe,
 		.valid = rocr_mm_valid,
 		.name = "rocr",
+		.unsubscribe_on_delete = false,
 	},
 };
 
@@ -404,6 +405,7 @@ static struct ofi_mem_monitor rocr_mm = {
 	.unsubscribe = rocr_mm_unsubscribe,
 	.valid = rocr_mm_valid,
 	.name = "rocr",
+	.unsubscribe_on_delete = false,
 };
 
 struct ofi_mem_monitor *rocr_monitor = &rocr_mm;

prov/util/src/uffd_mem_monitor.c

@@ -54,6 +54,7 @@ static struct ofi_uffd uffd = {
 	.monitor.start = ofi_uffd_start,
 	.monitor.stop = ofi_uffd_stop,
 	.monitor.name = "uffd",
+	.monitor.unsubscribe_on_delete = false,
 	.fd = -1,
 	.exit_pipe = { -1, -1 },
 };
@@ -266,6 +267,9 @@ static int ofi_uffd_register(const void *addr, size_t len, size_t page_size)
 	return 0;
 }
 
+/* Uffd subscription is by full page, which gets tracked in the kernel to
+ * an entire VMA.
+ */
 static int ofi_uffd_subscribe(struct ofi_mem_monitor *monitor,
 			      const void *addr, size_t len,
 			      union ofi_mr_hmem_info *hmem_info)
@@ -299,7 +303,7 @@ static int ofi_uffd_unregister(const void *addr, size_t len, size_t page_size)
 	return 0;
 }
 
-/* May be called from mr cache notifier callback */
+/* Uffd unsubscribes entire pages */
 static void ofi_uffd_unsubscribe(struct ofi_mem_monitor *monitor,
 				 const void *addr, size_t len,
 				 union ofi_mr_hmem_info *hmem_info)

prov/util/src/util_mr_cache.c

@@ -114,10 +114,19 @@ static void util_mr_entry_free(struct ofi_mr_cache *cache,
 static void util_mr_free_entry(struct ofi_mr_cache *cache,
 			       struct ofi_mr_entry *entry)
 {
+	enum fi_hmem_iface       iface = entry->info.iface;
+	struct ofi_mem_monitor   *monitor = cache->monitors[iface];
+
 	FI_DBG(cache->prov, FI_LOG_MR, "free %p (len: %zu)\n",
 	       entry->info.iov.iov_base, entry->info.iov.iov_len);
 
 	assert(!entry->node);
+
+	if (monitor->unsubscribe_on_delete)
+		ofi_monitor_unsubscribe(monitor, entry->info.iov.iov_base,
+					entry->info.iov.iov_len,
+					&entry->hmem_info);
+
 	cache->delete_region(cache, entry);
 	util_mr_entry_free(cache, entry);
 }

prov/util/src/xpmem_monitor.c

@@ -60,6 +60,7 @@ static struct ofi_mem_monitor xpmem_monitor_ = {
 	.unsubscribe = ofi_monitor_unsubscribe_no_op,
 	.valid = xpmem_monitor_valid,
 	.name = "xpmem",
+	.unsubscribe_on_delete = false,
 };
 
 struct ofi_mem_monitor *xpmem_monitor = &xpmem_monitor_;

prov/util/src/ze_ipc_monitor.c

@@ -65,6 +65,7 @@ static struct ofi_mem_monitor ze_ipc_monitor_ = {
 	.unsubscribe = ofi_monitor_unsubscribe_no_op,
 	.valid = ze_ipc_monitor_valid,
 	.name = "ze_ipc",
+	.unsubscribe_on_delete = false,
 };
 
 struct ofi_mem_monitor *ze_ipc_monitor = &ze_ipc_monitor_;

prov/util/src/ze_mem_monitor.c

@@ -113,6 +113,7 @@ static struct ofi_mem_monitor ze_mm = {
 	.unsubscribe = ze_mm_unsubscribe,
 	.valid = ze_mm_valid,
 	.name = "ze",
+	.unsubscribe_on_delete = false,
 };
 
 struct ofi_mem_monitor *ze_monitor = &ze_mm;