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mieq: Provide better adaptability and diagnostics during mieq overflow 

This patch changes from a static length event queue (512) to one that
starts at 128 and grows to 4096 as it overflows, logging each time it
grows.

This change also allows for multiple backtraces to be printed when the
server is wedged rather than just one.  This increased sampling should
help identify the true hog in cases where one backtrace might be
insufficient.

Signed-off-by: Jeremy Huddleston <jeremyhu@apple.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
This commit is contained in:
Jeremy Huddleston 2011-10-15 22:51:30 -07:00
parent 09eaa1f6f1
commit 7d153f25be
1 changed files with 128 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

165
mi/mieq.c
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@ -59,7 +59,11 @@ in this Software without prior written authorization from The Open Group.
# include <X11/extensions/dpmsconst.h>
#endif
#define QUEUE_SIZE 512
/* Maximum size should be initial size multiplied by a power of 2 */
#define QUEUE_INITIAL_SIZE 128
#define QUEUE_MAXIMUM_SIZE 4096
#define QUEUE_DROP_BACKTRACE_FREQUENCY 100
#define QUEUE_DROP_BACKTRACE_MAX 10
#define EnqueueScreen(dev) dev->spriteInfo->sprite->pEnqueueScreen
#define DequeueScreen(dev) dev->spriteInfo->sprite->pDequeueScreen
@ -74,7 +78,9 @@ typedef struct _EventQueue {
HWEventQueueType head, tail; /* long for SetInputCheck */
CARD32 lastEventTime; /* to avoid time running backwards */
int lastMotion; /* device ID if last event motion? */
EventRec events[QUEUE_SIZE]; /* static allocation for signals */
EventRec *events; /* our queue as an array */
size_t nevents; /* the number of buckets in our queue */
size_t dropped; /* counter for number of consecutive dropped events */
mieqHandler handlers[128]; /* custom event handler */
} EventQueueRec, *EventQueuePtr;
@ -99,25 +105,87 @@ static inline void wait_for_server_init(void) {
}
#endif
static size_t
mieqNumEnqueued(EventQueuePtr eventQueue) {
size_t n_enqueued = 0;
if (eventQueue->nevents) {
/* % is not well-defined with negative numbers... sigh */
n_enqueued = eventQueue->tail - eventQueue->head + eventQueue->nevents;
if (n_enqueued >= eventQueue->nevents)
n_enqueued -= eventQueue->nevents;
}
return n_enqueued;
}
/* Pre-condition: Called with miEventQueueMutex held */
static Bool
mieqGrowQueue(EventQueuePtr eventQueue, size_t new_nevents) {
size_t i, n_enqueued, first_hunk;
EventRec *new_events;
if (!eventQueue) {
ErrorF("[mi] mieqGrowQueue called with a NULL eventQueue\n");
return FALSE;
}
if (new_nevents <= eventQueue->nevents)
return FALSE;
new_events = calloc(new_nevents, sizeof(EventRec));
if (new_events == NULL) {
ErrorF("[mi] mieqGrowQueue memory allocation error.\n");
return FALSE;
}
n_enqueued = mieqNumEnqueued(eventQueue);
/* We block signals, so an mieqEnqueue triggered by SIGIO does not
* write to our queue as we are modifying it.
*/
OsBlockSignals();
/* First copy the existing events */
first_hunk = eventQueue->nevents - eventQueue->head;
memcpy(new_events,
&eventQueue->events[eventQueue->head],
first_hunk * sizeof(EventRec));
memcpy(&new_events[first_hunk],
eventQueue->events,
eventQueue->head * sizeof(EventRec));
/* Initialize the new portion */
for (i = eventQueue->nevents; i < new_nevents; i++) {
InternalEvent* evlist = InitEventList(1);
if (!evlist) {
size_t j;
for (j = 0; j < i; j++)
FreeEventList(new_events[j].events, 1);
free(new_events);
OsReleaseSignals();
return FALSE;
}
new_events[i].events = evlist;
}
/* And update our record */
eventQueue->tail = n_enqueued;
eventQueue->head = 0;
eventQueue->nevents = new_nevents;
free(eventQueue->events);
eventQueue->events = new_events;
OsReleaseSignals();
return TRUE;
}
Bool
mieqInit(void)
{
int i;
miEventQueue.head = miEventQueue.tail = 0;
memset(&miEventQueue, 0, sizeof(miEventQueue));
miEventQueue.lastEventTime = GetTimeInMillis ();
miEventQueue.lastMotion = FALSE;
for (i = 0; i < 128; i++)
miEventQueue.handlers[i] = NULL;
for (i = 0; i < QUEUE_SIZE; i++)
{
if (miEventQueue.events[i].events == NULL) {
InternalEvent* evlist = InitEventList(1);
if (!evlist)
FatalError("Could not allocate event queue.\n");
miEventQueue.events[i].events = evlist;
}
}
if(!mieqGrowQueue(&miEventQueue, QUEUE_INITIAL_SIZE))
FatalError("Could not allocate event queue.\n");
SetInputCheck(&miEventQueue.head, &miEventQueue.tail);
return TRUE;
@ -127,13 +195,14 @@ void
mieqFini(void)
{
int i;
for (i = 0; i < QUEUE_SIZE; i++)
for (i = 0; i < miEventQueue.nevents; i++)
{
if (miEventQueue.events[i].events != NULL) {
FreeEventList(miEventQueue.events[i].events, 1);
miEventQueue.events[i].events = NULL;
}
}
free(miEventQueue.events);
}
/*
@ -165,26 +234,31 @@ mieqEnqueue(DeviceIntPtr pDev, InternalEvent *e)
if (isMotion && isMotion == miEventQueue.lastMotion &&
oldtail != miEventQueue.head) {
oldtail = (oldtail - 1) % QUEUE_SIZE;
}
else {
static int stuck = 0;
oldtail = (oldtail - 1) % miEventQueue.nevents;
} else if (((oldtail + 1) % miEventQueue.nevents) == miEventQueue.head) {
/* Toss events which come in late. Usually this means your server's
* stuck in an infinite loop somewhere, but SIGIO is still getting
* handled. */
if (((oldtail + 1) % QUEUE_SIZE) == miEventQueue.head) {
if (!stuck) {
ErrorF("[mi] EQ overflowing. The server is probably stuck "
"in an infinite loop.\n");
xorg_backtrace();
stuck = 1;
* handled.
*/
miEventQueue.dropped++;
if (miEventQueue.dropped == 1) {
ErrorF("[mi] EQ overflowing. Additional events will be discarded until existing events are processed.\n");
xorg_backtrace();
ErrorF("[mi] These backtraces from mieqEnqueue may point to a culprit higher up the stack.\n");
ErrorF("[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) {
ErrorF("[mi] EQ overflow continuing. %lu events have been dropped.\n", miEventQueue.dropped);
if (miEventQueue.dropped / QUEUE_DROP_BACKTRACE_FREQUENCY == QUEUE_DROP_BACKTRACE_MAX) {
ErrorF("[mi] No further overflow reports will be reported until the clog is cleared.\n");
}
#ifdef XQUARTZ
pthread_mutex_unlock(&miEventQueueMutex);
#endif
return;
xorg_backtrace();
}
stuck = 0;
#ifdef XQUARTZ
pthread_mutex_unlock(&miEventQueueMutex);
#endif
return;
}
evlen = e->any.length;
@ -203,7 +277,7 @@ mieqEnqueue(DeviceIntPtr pDev, InternalEvent *e)
miEventQueue.events[oldtail].pDev = pDev;
miEventQueue.lastMotion = isMotion;
miEventQueue.tail = (oldtail + 1) % QUEUE_SIZE;
miEventQueue.tail = (oldtail + 1) % miEventQueue.nevents;
#ifdef XQUARTZ
pthread_mutex_unlock(&miEventQueueMutex);
#endif
@ -437,11 +511,28 @@ mieqProcessInputEvents(void)
static InternalEvent event;
DeviceIntPtr dev = NULL,
master = NULL;
size_t n_enqueued;
#ifdef XQUARTZ
pthread_mutex_lock(&miEventQueueMutex);
#endif
/* Grow our queue if we are reaching capacity: > 50% full */
n_enqueued = mieqNumEnqueued(&miEventQueue);
if (n_enqueued >= (miEventQueue.nevents >> 1) &&
miEventQueue.nevents < QUEUE_MAXIMUM_SIZE) {
ErrorF("[mi] Increasing EQ size to %lu to prevent dropped events.\n", 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", miEventQueue.dropped);
ErrorF("[mi] This may be caused my a misbehaving driver monopolizing the server's resources.\n");
miEventQueue.dropped = 0;
}
while (miEventQueue.head != miEventQueue.tail) {
e = &miEventQueue.events[miEventQueue.head];
@ -449,7 +540,7 @@ mieqProcessInputEvents(void)
dev = e->pDev;
screen = e->pScreen;
miEventQueue.head = (miEventQueue.head + 1) % QUEUE_SIZE;
miEventQueue.head = (miEventQueue.head + 1) % miEventQueue.nevents;
#ifdef XQUARTZ
pthread_mutex_unlock(&miEventQueueMutex);