From e42ec63bfd7ada1087a00ca3ccc39c95679b7fab Mon Sep 17 00:00:00 2001
From: Andrey Kleshchev <117672381+akleshchev@users.noreply.github.com>
Date: Fri, 23 Jan 2026 22:51:27 +0200
Subject: #5046 Fix a long freeze when fetching inventory

---
 indra/llcommon/lleventcoro.cpp | 12 ++++++++++++
 indra/llcommon/lleventcoro.h   |  5 +++++
 indra/newview/llaisapi.cpp     |  7 ++++++-
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/indra/llcommon/lleventcoro.cpp b/indra/llcommon/lleventcoro.cpp
index e1fc4764f6..bb2cd4fb2e 100644
--- a/indra/llcommon/lleventcoro.cpp
+++ b/indra/llcommon/lleventcoro.cpp
@@ -137,6 +137,18 @@ void llcoro::suspendUntilTimeout(float seconds)
     suspendUntilEventOnWithTimeout(bogus, seconds, timedout);
 }
 
+void llcoro::suspendUntilNextFrame()
+{
+    LLCoros::checkStop();
+    LLCoros::TempStatus st("waiting for next frame");
+
+    // Listen for the next event on the "mainloop" event pump.
+    // Once per frame we get mainloop.post(newFrame);
+    LLEventPumpOrPumpName mainloop_pump("mainloop");
+    // Wait for the next event (the event data is ignored).
+    suspendUntilEventOn(mainloop_pump);
+}
+
 namespace
 {
 
diff --git a/indra/llcommon/lleventcoro.h b/indra/llcommon/lleventcoro.h
index 492563bb98..25a8a98e36 100644
--- a/indra/llcommon/lleventcoro.h
+++ b/indra/llcommon/lleventcoro.h
@@ -84,6 +84,11 @@ void suspend();
  */
 void suspendUntilTimeout(float seconds);
 
+/**
+ * Yield control from a coroutine until the next mainloop's newFrame event.
+ */
+void suspendUntilNextFrame();
+
 /**
  * Post specified LLSD event on the specified LLEventPump, then suspend for a
  * response on specified other LLEventPump. This is more than mere
diff --git a/indra/newview/llaisapi.cpp b/indra/newview/llaisapi.cpp
index 1da1647fe8..9c76f56ef3 100644
--- a/indra/newview/llaisapi.cpp
+++ b/indra/newview/llaisapi.cpp
@@ -1060,7 +1060,12 @@ void AISUpdate::checkTimeout()
 {
     if (mTimer.hasExpired())
     {
-        llcoro::suspend();
+        // If we are taking too long, don't starve other tasks,
+        // yield to mainloop.
+        // If we use normal suspend(), there will be a chance of
+        // waking up from other suspends, before main coro had
+        // a chance, so wait for a frame tick instead.
+        llcoro::suspendUntilNextFrame();
         LLCoros::checkStop();
         mTimer.setTimerExpirySec(AIS_EXPIRY_SECONDS);
     }
-- 
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