Modules TSC: Release the GIL for all the time we are blocked.

Instead of giving the module background operations just a small time to
run in the beforeSleep() function, we can have the lock released for all
the time we are blocked in the multiplexing syscall.

1 files changed, 42 insertions, 0 deletions

diff --git a/src/modules/helloblock.c b/src/modules/helloblock.c
index 71ec9b121..e760e33fb 100644
--- a/src/modules/helloblock.c
+++ b/src/modules/helloblock.c
@@ -105,6 +105,45 @@ int HelloBlock_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int a
     return REDISMODULE_OK;
 }
 
+/* The thread entry point that actually executes the blocking part
+ * of the command HELLO.KEYS. */
+void *HelloKeys_ThreadMain(void *arg) {
+    RedisModuleBlockedClient *bc = arg;
+    RedisModuleCtx *ctx = RedisModule_GetThreadSafeContext(bc);
+
+    RedisModule_ThreadSafeContextLock(ctx);
+    RedisModule_ReplyWithLongLong(ctx,1234);
+    RedisModule_ThreadSafeContextUnlock(ctx);
+
+    RedisModule_UnblockClient(bc,NULL);
+    return NULL;
+}
+
+/* HELLO.KEYS -- Return all the keys in the current database without blocking
+ * the server. The keys do not represent a point-in-time state so only the keys
+ * that were in the database from the start to the end are guaranteed to be
+ * there. */
+int HelloKeys_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+    REDISMODULE_NOT_USED(argv);
+    if (argc != 1) return RedisModule_WrongArity(ctx);
+
+    pthread_t tid;
+
+    /* Note that when blocking the client we do not set any callback: no
+     * timeout is possible since we passed '0', nor we need a reply callback
+     * because we'll use the thread safe context to accumulate a reply. */
+    RedisModuleBlockedClient *bc = RedisModule_BlockClient(ctx,NULL,NULL,NULL,0);
+
+    /* Now that we setup a blocking client, we need to pass the control
+     * to the thread. However we need to pass arguments to the thread:
+     * the reference to the blocked client handle. */
+    if (pthread_create(&tid,NULL,HelloKeys_ThreadMain,bc) != 0) {
+        RedisModule_AbortBlock(bc);
+        return RedisModule_ReplyWithError(ctx,"-ERR Can't start thread");
+    }
+    return REDISMODULE_OK;
+}
+
 /* This function must be present on each Redis module. It is used in order to
  * register the commands into the Redis server. */
 int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
@@ -117,6 +156,9 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
     if (RedisModule_CreateCommand(ctx,"hello.block",
         HelloBlock_RedisCommand,"",0,0,0) == REDISMODULE_ERR)
         return REDISMODULE_ERR;
+    if (RedisModule_CreateCommand(ctx,"hello.keys",
+        HelloKeys_RedisCommand,"",0,0,0) == REDISMODULE_ERR)
+        return REDISMODULE_ERR;
 
     return REDISMODULE_OK;
 }