[SCM] Samba Shared Repository - branch master updated

[Volker Lendecke]

The branch, master has been updated
       via  60550fbe184 Fix starvation of pending writes in CTDB queues
      from  6d3cfb4b1c6 s4:torture: Initialize param arrays

https://git.samba.org/?p=samba.git;a=shortlog;h=master


- Log -----------------------------------------------------------------
commit 60550fbe184a5cefa55a8f0bab508f70def7a684
Author: Xavi Hernandez <xhernandez at redhat.com>
Date:   Thu Jun 27 15:41:19 2024 +0200

    Fix starvation of pending writes in CTDB queues
    
    CTDB uses a queue to receive requests and send answers. It works
    asynchronously using the tevent framework. However there was an issue
    that gave priority to the receiving side so, when a request was
    processed and the answer posted to the queue, if another incoming
    request arrived, it was served before sending the previous answer.
    
    This scenario could repeat for long periods of time if the frequency of
    incoming requests was high enough.
    
    Eventually, a small time gap between incoming request gave a chance to
    process the pending output queue, sending many answers in a burst.
    
    This patch makes sure that both queues (input and output) are processed
    if the event contains the appropriate flag.
    
    Signed-off-by: Xavi Hernandez <xhernandez at redhat.com>
    Reviewed-by: Volker Lendecke <vl at samba.org>
    Reviewed-by: Martin Schwenke <martin at meltin.net>
    
    Autobuild-User(master): Volker Lendecke <vl at samba.org>
    Autobuild-Date(master): Mon Jul  1 09:17:43 UTC 2024 on atb-devel-224

-----------------------------------------------------------------------

Summary of changes:
 ctdb/common/ctdb_io.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)


Changeset truncated at 500 lines:

diff --git a/ctdb/common/ctdb_io.c b/ctdb/common/ctdb_io.c
index bf8bc73b77d..9ac9b84a7fb 100644
--- a/ctdb/common/ctdb_io.c
+++ b/ctdb/common/ctdb_io.c
@@ -272,7 +272,7 @@ static void queue_dead(struct tevent_context *ev, struct tevent_immediate *im,
 /*
   called when an incoming connection is writeable
 */
-static void queue_io_write(struct ctdb_queue *queue)
+static bool queue_io_write(struct ctdb_queue *queue)
 {
 	while (queue->out_queue) {
 		struct ctdb_queue_pkt *pkt = queue->out_queue;
@@ -294,14 +294,14 @@ static void queue_io_write(struct ctdb_queue *queue)
 			queue->fd = -1;
 			tevent_schedule_immediate(queue->im, queue->ctdb->ev,
 						  queue_dead, queue);
-			return;
+			return false;
 		}
-		if (n <= 0) return;
+		if (n <= 0) return true;
 		
 		if (n != pkt->length) {
 			pkt->length -= n;
 			pkt->data += n;
-			return;
+			return true;
 		}
 
 		DLIST_REMOVE(queue->out_queue, pkt);
@@ -310,6 +310,8 @@ static void queue_io_write(struct ctdb_queue *queue)
 	}
 
 	TEVENT_FD_NOT_WRITEABLE(queue->fde);
+
+	return true;
 }
 
 /*
@@ -320,10 +322,13 @@ static void queue_io_handler(struct tevent_context *ev, struct tevent_fd *fde,
 {
 	struct ctdb_queue *queue = talloc_get_type(private_data, struct ctdb_queue);
 
+	if (flags & TEVENT_FD_WRITE) {
+		if (!queue_io_write(queue)) {
+			return;
+		}
+	}
 	if (flags & TEVENT_FD_READ) {
 		queue_io_read(queue);
-	} else {
-		queue_io_write(queue);
 	}
 }
 


-- 
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