[PATCH xserver 5/8] mi: Grow event queue while reading events
Keith Packard
keithp at keithp.com
Wed Dec 9 15:12:39 PST 2015
Now that events are read at normal process time, we can use malloc to
grow the event queue instead of discarding events.
Signed-off-by: Keith Packard <keithp at keithp.com>
---
mi/mieq.c | 103 +++++++++++++++++++-------------------------------------------
1 file changed, 32 insertions(+), 71 deletions(-)
diff --git a/mi/mieq.c b/mi/mieq.c
index 8a67213..f2db5a6 100644
--- a/mi/mieq.c
+++ b/mi/mieq.c
@@ -119,7 +119,7 @@ mieqNumEnqueued(EventQueuePtr eventQueue)
return n_enqueued;
}
-/* Pre-condition: Called with miEventQueueMutex held */
+/* Pre-condition: Called with input_lock held */
static Bool
mieqGrowQueue(EventQueuePtr eventQueue, size_t new_nevents)
{
@@ -142,11 +142,6 @@ mieqGrowQueue(EventQueuePtr eventQueue, size_t new_nevents)
n_enqueued = mieqNumEnqueued(eventQueue);
- /* We lock input, so an mieqEnqueue does not
- * write to our queue as we are modifying it.
- */
- input_lock();
-
/* First copy the existing events */
first_hunk = eventQueue->nevents - eventQueue->head;
memcpy(new_events,
@@ -178,7 +173,6 @@ mieqGrowQueue(EventQueuePtr eventQueue, size_t new_nevents)
free(eventQueue->events);
eventQueue->events = new_events;
- input_unlock();
return TRUE;
}
@@ -188,8 +182,10 @@ mieqInit(void)
memset(&miEventQueue, 0, sizeof(miEventQueue));
miEventQueue.lastEventTime = GetTimeInMillis();
+ input_lock();
if (!mieqGrowQueue(&miEventQueue, QUEUE_INITIAL_SIZE))
FatalError("Could not allocate event queue.\n");
+ input_unlock();
SetInputCheck(&miEventQueue.head, &miEventQueue.tail);
return TRUE;
@@ -209,32 +205,9 @@ mieqFini(void)
free(miEventQueue.events);
}
-/* This function will determine if the given event is allowed to used the reserved
- * queue space.
- */
-static Bool
-mieqReservedCandidate(InternalEvent *e)
-{
- switch (e->any.type) {
- case ET_KeyRelease:
- case ET_ButtonRelease:
-#if XFreeXDGA
- case ET_DGAEvent:
-#endif
- case ET_RawKeyRelease:
- case ET_RawButtonRelease:
- case ET_XQuartz:
- return TRUE;
- default:
- return FALSE;
- }
-}
-
/*
* Must be reentrant with ProcessInputEvents. Assumption: mieqEnqueue
- * will never be interrupted. If this is called from both signal
- * handlers and regular code, make sure the signal is suspended when
- * called from regular code.
+ * will never be interrupted. Must be called with input_lock held
*/
void
@@ -263,36 +236,36 @@ mieqEnqueue(DeviceIntPtr pDev, InternalEvent *e)
oldtail != miEventQueue.head) {
oldtail = (oldtail - 1) % miEventQueue.nevents;
}
- else if ((n_enqueued + 1 == miEventQueue.nevents) ||
- ((n_enqueued + 1 >= miEventQueue.nevents - QUEUE_RESERVED_SIZE) &&
- !mieqReservedCandidate(e))) {
- /* Toss events which come in late. Usually this means your server's
- * stuck in an infinite loop somewhere, but SIGIO is still getting
- * handled.
- */
- miEventQueue.dropped++;
- if (miEventQueue.dropped == 1) {
- ErrorFSigSafe("[mi] EQ overflowing. Additional events will be "
- "discarded until existing events are processed.\n");
- xorg_backtrace();
- ErrorFSigSafe("[mi] These backtraces from mieqEnqueue may point to "
- "a culprit higher up the stack.\n");
- ErrorFSigSafe("[mi] mieq is *NOT* the cause. It is a victim.\n");
- }
- else if (miEventQueue.dropped % QUEUE_DROP_BACKTRACE_FREQUENCY == 0 &&
- miEventQueue.dropped / QUEUE_DROP_BACKTRACE_FREQUENCY <=
- QUEUE_DROP_BACKTRACE_MAX) {
- ErrorFSigSafe("[mi] EQ overflow continuing. %zu events have been "
- "dropped.\n", miEventQueue.dropped);
- if (miEventQueue.dropped / QUEUE_DROP_BACKTRACE_FREQUENCY ==
- QUEUE_DROP_BACKTRACE_MAX) {
- ErrorFSigSafe("[mi] No further overflow reports will be "
- "reported until the clog is cleared.\n");
+ else if (n_enqueued + 1 == miEventQueue.nevents) {
+ if (!mieqGrowQueue(&miEventQueue, miEventQueue.nevents << 1)) {
+ /* Toss events which come in late. Usually this means your server's
+ * stuck in an infinite loop somewhere, but SIGIO is still getting
+ * handled.
+ */
+ miEventQueue.dropped++;
+ if (miEventQueue.dropped == 1) {
+ ErrorFSigSafe("[mi] EQ overflowing. Additional events will be "
+ "discarded until existing events are processed.\n");
+ xorg_backtrace();
+ ErrorFSigSafe("[mi] These backtraces from mieqEnqueue may point to "
+ "a culprit higher up the stack.\n");
+ ErrorFSigSafe("[mi] mieq is *NOT* the cause. It is a victim.\n");
+ }
+ else if (miEventQueue.dropped % QUEUE_DROP_BACKTRACE_FREQUENCY == 0 &&
+ miEventQueue.dropped / QUEUE_DROP_BACKTRACE_FREQUENCY <=
+ QUEUE_DROP_BACKTRACE_MAX) {
+ ErrorFSigSafe("[mi] EQ overflow continuing. %zu events have been "
+ "dropped.\n", miEventQueue.dropped);
+ if (miEventQueue.dropped / QUEUE_DROP_BACKTRACE_FREQUENCY ==
+ QUEUE_DROP_BACKTRACE_MAX) {
+ ErrorFSigSafe("[mi] No further overflow reports will be "
+ "reported until the clog is cleared.\n");
+ }
+ xorg_backtrace();
}
- xorg_backtrace();
+ return;
}
-
- return;
+ oldtail = miEventQueue.tail;
}
evlen = e->any.length;
@@ -556,7 +529,6 @@ mieqProcessInputEvents(void)
ScreenPtr screen;
InternalEvent event;
DeviceIntPtr dev = NULL, master = NULL;
- size_t n_enqueued;
static Bool inProcessInputEvents = FALSE;
input_lock();
@@ -569,17 +541,6 @@ mieqProcessInputEvents(void)
BUG_WARN_MSG(inProcessInputEvents, "[mi] mieqProcessInputEvents() called recursively.\n");
inProcessInputEvents = TRUE;
- /* Grow our queue if we are reaching capacity: < 2 * QUEUE_RESERVED_SIZE remaining */
- n_enqueued = mieqNumEnqueued(&miEventQueue);
- if (n_enqueued >= (miEventQueue.nevents - (2 * QUEUE_RESERVED_SIZE)) &&
- miEventQueue.nevents < QUEUE_MAXIMUM_SIZE) {
- ErrorF("[mi] Increasing EQ size to %lu to prevent dropped events.\n",
- (unsigned long) (miEventQueue.nevents << 1));
- if (!mieqGrowQueue(&miEventQueue, miEventQueue.nevents << 1)) {
- ErrorF("[mi] Increasing the size of EQ failed.\n");
- }
- }
-
if (miEventQueue.dropped) {
ErrorF("[mi] EQ processing has resumed after %lu dropped events.\n",
(unsigned long) miEventQueue.dropped);
--
2.6.2
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