Unify beforeSleep handling

Former-commit-id: 1cb48c7bf6a7e91e728a677902a7bfc64fe80dd6

src/aof.cpp

@@ -751,6 +751,7 @@ struct client *createAOFClient(void) {
     c->bufpos = 0;
     c->flags = 0;
     c->fPendingAsyncWrite = FALSE;
+    c->fPendingAsyncWriteHandler = FALSE;
     c->btype = BLOCKED_NONE;
     /* We set the fake client as a replica waiting for the synchronization
      * so that Redis will not try to send replies to this client. */

src/networking.cpp

@@ -135,6 +135,7 @@ client *createClient(connection *conn, int iel) {
     c->sentlenAsync = 0;
     c->flags = 0;
     c->fPendingAsyncWrite = FALSE;
+    c->fPendingAsyncWriteHandler = FALSE;
     c->ctime = c->lastinteraction = g_pserver->unixtime;
     /* If the default user does not require authentication, the user is
      * directly authenticated. */
@@ -1850,29 +1851,21 @@ void ProcessPendingAsyncWrites()
         
         std::atomic_thread_fence(std::memory_order_seq_cst);
         
-        if (c->casyncOpsPending == 0)
-        {
         if (FCorrectThread(c))
         {
             prepareClientToWrite(c, false); // queue an event
         }
         else
         {
-                // We need to start the write on the client's thread
-                if (aePostFunction(g_pserver->rgthreadvar[c->iel].el, [c]{
-                        // Install a write handler.  Don't do the actual write here since we don't want
-                        //  to duplicate the throttling and safety mechanisms of the normal write code
-                        std::lock_guard<decltype(c->lock)> lock(c->lock);
-                        serverAssert(c->casyncOpsPending > 0);
-                        c->casyncOpsPending--;
+            if (!c->fPendingAsyncWriteHandler) {
+                c->fPendingAsyncWriteHandler = true;
+                bool fResult = c->postFunction([](client *c) {
+                    c->fPendingAsyncWriteHandler = false;
                     connSetWriteHandler(c->conn, sendReplyToClient, true);
-                    }, false) == AE_ERR
-                )
-                {
-                    // Posting the function failed
-                    continue;   // We can retry later in the cron
-                }
-                ++c->casyncOpsPending; // race is handled by the client lock in the lambda
+                });
+
+                if (!fResult)
+                    c->fPendingAsyncWriteHandler = false;   // if we failed to set the handler then prevent this from never being reset
             }
         }
     }

src/server.cpp

@@ -1908,8 +1908,6 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
         processUnblockedClients(IDX_EVENT_LOOP_MAIN);
     }
         
-    ProcessPendingAsyncWrites();    // This is really a bug, but for now catch any laggards that didn't clean up
-        
     /* Software watchdog: deliver the SIGALRM that will reach the signal
      * handler if we don't return here fast enough. */
     if (g_pserver->watchdog_period) watchdogScheduleSignal(g_pserver->watchdog_period);
@@ -2143,6 +2141,9 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
                           &ei);
 
 
+    /* CRON functions may trigger async writes, so do this last */
+    ProcessPendingAsyncWrites();
+
     g_pserver->cronloops++;
     return 1000/g_pserver->hz;
 }
@@ -2192,6 +2193,7 @@ extern int ProcessingEventsWhileBlocked;
  * call some other low-risk functions. */
 void beforeSleep(struct aeEventLoop *eventLoop) {
     UNUSED(eventLoop);
+    int iel = ielFromEventLoop(eventLoop);
 
     /* Handle precise timeouts of blocked clients. */
     handleBlockedClientsTimeout();
@@ -2225,9 +2227,9 @@ void beforeSleep(struct aeEventLoop *eventLoop) {
     if (moduleCount()) moduleHandleBlockedClients(ielFromEventLoop(eventLoop));
 
     /* Try to process pending commands for clients that were just unblocked. */
-    if (listLength(g_pserver->rgthreadvar[IDX_EVENT_LOOP_MAIN].unblocked_clients))
+    if (listLength(g_pserver->rgthreadvar[iel].unblocked_clients))
     {
-        processUnblockedClients(IDX_EVENT_LOOP_MAIN);
+        processUnblockedClients(iel);
     }
 
     /* Send all the slaves an ACK request if at least one client blocked
@@ -2258,11 +2260,11 @@ void beforeSleep(struct aeEventLoop *eventLoop) {
     /* Handle writes with pending output buffers. */
     int aof_state = g_pserver->aof_state;
     aeReleaseLock();
-    handleClientsWithPendingWrites(IDX_EVENT_LOOP_MAIN, aof_state);
+    handleClientsWithPendingWrites(iel, aof_state);
     aeAcquireLock();
 
     /* Close clients that need to be closed asynchronous */
-    freeClientsInAsyncFreeQueue(IDX_EVENT_LOOP_MAIN);
+    freeClientsInAsyncFreeQueue(iel);
 
     /* Before we are going to sleep, let the threads access the dataset by
      * releasing the GIL. Redis main thread will not touch anything at this
@@ -2958,7 +2960,7 @@ static void initServerThread(struct redisServerThreadVars *pvar, int fMain)
     pvar->tlsfd_count = 0;
     pvar->cclients = 0;
     pvar->el = aeCreateEventLoop(g_pserver->maxclients+CONFIG_FDSET_INCR);
-    aeSetBeforeSleepProc(pvar->el, fMain ? beforeSleep : beforeSleepLite, fMain ? 0 : AE_SLEEP_THREADSAFE);
+    aeSetBeforeSleepProc(pvar->el, beforeSleep, 0);
     aeSetAfterSleepProc(pvar->el, afterSleep, AE_SLEEP_THREADSAFE);
     pvar->current_client = nullptr;
     pvar->clients_paused = 0;

src/server.h

@@ -1268,6 +1268,7 @@ typedef struct client {
     std::atomic<uint64_t> flags;              /* Client flags: CLIENT_* macros. */
     int casyncOpsPending;
     int fPendingAsyncWrite; /* NOTE: Not a flag because it is written to outside of the client lock (locked by the global lock instead) */
+    int fPendingAsyncWriteHandler;
     int authenticated;      /* Needed when the default user requires auth. */
     int replstate;          /* Replication state if this is a replica. */
     int repl_put_online_on_ack; /* Install replica write handler on ACK. */

tests/test_helper.tcl

@@ -428,6 +428,7 @@ proc signal_idle_client fd {
         lappend ::active_clients $fd
         incr ::next_test
         if {$::loop && $::next_test == [llength $::all_tests]} {
+            incr ::loop -1
             set ::next_test 0
         }
     } elseif {[llength $::run_solo_tests] != 0 && [llength $::active_clients] == 0} {
@@ -612,7 +613,10 @@ for {set j 0} {$j < [llength $argv]} {incr j} {
     } elseif {$opt eq {--stop}} {
         set ::stop_on_failure 1
     } elseif {$opt eq {--loop}} {
-        set ::loop 1
+        set ::loop 1000
+    } elseif {$opt eq {--loopn}} {
+        set ::loop [expr $arg - 1]
+        incr j
     } elseif {$opt eq {--timeout}} {
         set ::timeout $arg
         incr j