From 991ca9fef80d2c41f27b35718d8ea71dff44eafa Mon Sep 17 00:00:00 2001
From: Craig Tiller <ctiller@google.com>
Date: Tue, 3 Mar 2015 09:59:22 -0800
Subject: [PATCH] Allow only one thread to complete ioreqs at once
Otherwise we can get a total-queue-ordering violation and complete some
ioreqs out-of-order. This leads to events being pushed to the completion
queue out-of-order, and that leads to applications believing streams are
completed before receiving the last message.
---
src/core/surface/call.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/src/core/surface/call.c b/src/core/surface/call.c
index 7cf3c0e4fd..b2033f3dc0 100644
--- a/src/core/surface/call.c
+++ b/src/core/surface/call.c
@@ -140,6 +140,8 @@ struct grpc_call {
gpr_uint8 have_alarm;
/* are we currently performing a send operation */
gpr_uint8 sending;
+ /* are we currently completing requests */
+ gpr_uint8 completing;
/* pairs with completed_requests */
gpr_uint8 num_completed_requests;
/* flag that we need to request more data */
@@ -357,7 +359,7 @@ static void lock(grpc_call *call) { gpr_mu_lock(&call->mu); }
static void unlock(grpc_call *call) {
send_action sa = SEND_NOTHING;
completed_request completed_requests[GRPC_IOREQ_OP_COUNT];
- int num_completed_requests = call->num_completed_requests;
+ int completing_requests = 0;
int need_more_data =
call->need_more_data &&
(call->write_state >= WRITE_STATE_STARTED || !call->is_client);
@@ -367,10 +369,12 @@ static void unlock(grpc_call *call) {
call->need_more_data = 0;
}
- if (num_completed_requests != 0) {
+ if (!call->completing && call->num_completed_requests != 0) {
+ completing_requests = call->num_completed_requests;
memcpy(completed_requests, call->completed_requests,
sizeof(completed_requests));
call->num_completed_requests = 0;
+ call->completing = 1;
}
if (!call->sending) {
@@ -391,9 +395,14 @@ static void unlock(grpc_call *call) {
enact_send_action(call, sa);
}
- for (i = 0; i < num_completed_requests; i++) {
- completed_requests[i].on_complete(call, completed_requests[i].status,
- completed_requests[i].user_data);
+ if (completing_requests > 0) {
+ for (i = 0; i < completing_requests; i++) {
+ completed_requests[i].on_complete(call, completed_requests[i].status,
+ completed_requests[i].user_data);
+ }
+ lock(call);
+ call->completing = 0;
+ unlock(call);
}
}
--
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