Commit 9fc59c6e authored by sof's avatar sof
Browse files

[project @ 2003-09-12 16:16:43 by sof]

- awaitRequests() comments
- code reformatting

Merge to STABLE
parent 546e865b
......@@ -16,7 +16,7 @@
* Overview:
*
* Haskell code issue asynchronous I/O requests via the
* asyncRead# and asyncWrite# primops. These cause addIORequest()
* async{Read,Write,DoOp}# primops. These cause addIORequest()
* to be invoked, which forwards the request to the underlying
* asynchronous I/O subsystem. Each request is tagged with a unique
* ID.
......@@ -35,9 +35,9 @@
*/
typedef struct CompletedReq {
unsigned int reqID;
int len;
int errCode;
unsigned int reqID;
int len;
int errCode;
} CompletedReq;
#define MAX_REQUESTS 200
......@@ -57,30 +57,32 @@ onIOComplete(unsigned int reqID,
void* buf STG_UNUSED,
int errCode)
{
/* Deposit result of request in queue/table */
EnterCriticalSection(&queue_lock);
if (completed_hw == MAX_REQUESTS) {
/* Not likely */
fprintf(stderr, "Request table overflow (%d); dropping.\n", reqID);
fflush(stderr);
} else {
/* Deposit result of request in queue/table */
EnterCriticalSection(&queue_lock);
if (completed_hw == MAX_REQUESTS) {
/* Not likely */
fprintf(stderr, "Request table overflow (%d); dropping.\n", reqID);
fflush(stderr);
} else {
#if 0
fprintf(stderr, "onCompl: %d %d %d %d %d\n", reqID, len, errCode, issued_reqs, completed_hw); fflush(stderr);
fprintf(stderr, "onCompl: %d %d %d %d %d\n",
reqID, len, errCode, issued_reqs, completed_hw);
fflush(stderr);
#endif
completedTable[completed_hw].reqID = reqID;
completedTable[completed_hw].len = len;
completedTable[completed_hw].errCode = errCode;
completed_hw++;
issued_reqs--;
if (completed_hw == 1) {
/* The event is used to wake up the scheduler thread should it
* be blocked waiting for requests to complete. It reset once
* that thread has cleared out the request queue/table.
*/
SetEvent(completed_req_event);
completedTable[completed_hw].reqID = reqID;
completedTable[completed_hw].len = len;
completedTable[completed_hw].errCode = errCode;
completed_hw++;
issued_reqs--;
if (completed_hw == 1) {
/* The event is used to wake up the scheduler thread should it
* be blocked waiting for requests to complete. It reset once
* that thread has cleared out the request queue/table.
*/
SetEvent(completed_req_event);
}
}
}
LeaveCriticalSection(&queue_lock);
LeaveCriticalSection(&queue_lock);
}
unsigned int
......@@ -90,163 +92,196 @@ addIORequest(int fd,
int len,
char* buf)
{
EnterCriticalSection(&queue_lock);
issued_reqs++;
LeaveCriticalSection(&queue_lock);
EnterCriticalSection(&queue_lock);
issued_reqs++;
LeaveCriticalSection(&queue_lock);
#if 0
fprintf(stderr, "addIOReq: %d %d %d\n", fd, forWriting, len); fflush(stderr);
fprintf(stderr, "addIOReq: %d %d %d\n", fd, forWriting, len); fflush(stderr);
#endif
return AddIORequest(fd,forWriting,isSock,len,buf,onIOComplete);
return AddIORequest(fd,forWriting,isSock,len,buf,onIOComplete);
}
unsigned int
addDelayRequest(int msecs)
{
EnterCriticalSection(&queue_lock);
issued_reqs++;
LeaveCriticalSection(&queue_lock);
EnterCriticalSection(&queue_lock);
issued_reqs++;
LeaveCriticalSection(&queue_lock);
#if 0
fprintf(stderr, "addDelayReq: %d\n", msecs); fflush(stderr);
fprintf(stderr, "addDelayReq: %d\n", msecs); fflush(stderr);
#endif
return AddDelayRequest(msecs,onIOComplete);
return AddDelayRequest(msecs,onIOComplete);
}
unsigned int
addDoProcRequest(void* proc, void* param)
{
EnterCriticalSection(&queue_lock);
issued_reqs++;
LeaveCriticalSection(&queue_lock);
EnterCriticalSection(&queue_lock);
issued_reqs++;
LeaveCriticalSection(&queue_lock);
#if 0
fprintf(stderr, "addProcReq: %p %p\n", proc, param); fflush(stderr);
fprintf(stderr, "addProcReq: %p %p\n", proc, param); fflush(stderr);
#endif
return AddProcRequest(proc,param,onIOComplete);
return AddProcRequest(proc,param,onIOComplete);
}
int
startupAsyncIO()
{
if (!StartIOManager()) {
return 0;
}
InitializeCriticalSection(&queue_lock);
/* Create a pair of events:
*
* - completed_req_event -- signals the deposit of request result; manual reset.
* - abandon_req_wait -- external OS thread tells current RTS/Scheduler
* thread to abandon wait for IO request completion.
* Auto reset.
*/
completed_req_event = CreateEvent (NULL, TRUE, FALSE, NULL);
abandon_req_wait = CreateEvent (NULL, FALSE, FALSE, NULL);
wait_handles[0] = completed_req_event;
wait_handles[1] = abandon_req_wait;
completed_hw = 0;
return ( completed_req_event != INVALID_HANDLE_VALUE &&
abandon_req_wait != INVALID_HANDLE_VALUE );
if (!StartIOManager()) {
return 0;
}
InitializeCriticalSection(&queue_lock);
/* Create a pair of events:
*
* - completed_req_event -- signals the deposit of request result; manual reset.
* - abandon_req_wait -- external OS thread tells current RTS/Scheduler
* thread to abandon wait for IO request completion.
* Auto reset.
*/
completed_req_event = CreateEvent (NULL, TRUE, FALSE, NULL);
abandon_req_wait = CreateEvent (NULL, FALSE, FALSE, NULL);
wait_handles[0] = completed_req_event;
wait_handles[1] = abandon_req_wait;
completed_hw = 0;
return ( completed_req_event != INVALID_HANDLE_VALUE &&
abandon_req_wait != INVALID_HANDLE_VALUE );
}
void
shutdownAsyncIO()
{
CloseHandle(completed_req_event);
ShutdownIOManager();
CloseHandle(completed_req_event);
ShutdownIOManager();
}
/*
* Function: awaitRequests(wait)
*
* Check for the completion of external IO work requests. Worker
* threads signal completion of IO requests by depositing them
* in a table (completedTable). awaitRequests() matches up
* requests in that table with threads on the blocked_queue,
* making the threads whose IO requests have completed runnable
* again.
*
* awaitRequests() is called by the scheduler periodically _or_ if
* it is out of work, and need to wait for the completion of IO
* requests to make further progress. In the latter scenario,
* awaitRequests() will simply block waiting for worker threads
* to complete if the 'completedTable' is empty.
*/
int
awaitRequests(rtsBool wait)
{
start:
#if 0
fprintf(stderr, "awaitRequests: %d %d %d\n", issued_reqs, completed_hw, wait); fflush(stderr);
fprintf(stderr, "awaitRequests(): %d %d %d\n", issued_reqs, completed_hw, wait);
fflush(stderr);
#endif
EnterCriticalSection(&queue_lock);
/* Nothing immediately available & we won't wait */
if ((!wait && completed_hw == 0) ||
(issued_reqs == 0 && completed_hw == 0)) {
LeaveCriticalSection(&queue_lock);
return 0;
}
if (completed_hw == 0) {
/* empty table, drop lock and wait */
LeaveCriticalSection(&queue_lock);
if (wait) {
DWORD dwRes = WaitForMultipleObjects(2, wait_handles, FALSE, INFINITE);
switch (dwRes) {
case WAIT_OBJECT_0:
break;
case WAIT_OBJECT_0 + 1:
case WAIT_TIMEOUT:
EnterCriticalSection(&queue_lock);
/* Nothing immediately available & we won't wait */
if ((!wait && completed_hw == 0) ||
(issued_reqs == 0 && completed_hw == 0)) {
LeaveCriticalSection(&queue_lock);
return 0;
default:
fprintf(stderr, "awaitRequests: unexpected wait return code %lu\n", dwRes); fflush(stderr);
return 0;
}
} else {
return 0; /* cannot happen */
}
goto start;
} else {
int i;
StgTSO *tso, *prev;
for (i=0; i < completed_hw; i++) {
unsigned int rID = completedTable[i].reqID;
prev = NULL;
for(tso = blocked_queue_hd ; tso != END_TSO_QUEUE; prev = tso, tso = tso->link) {
switch(tso->why_blocked) {
case BlockedOnRead:
case BlockedOnWrite:
case BlockedOnDoProc:
if (tso->block_info.async_result->reqID == rID) {
/* Found the thread blocked waiting on request; stodgily fill
* in its result block.
if (completed_hw == 0) {
/* empty table, drop lock and wait */
LeaveCriticalSection(&queue_lock);
if ( wait && !interrupted ) {
DWORD dwRes = WaitForMultipleObjects(2, wait_handles, FALSE, INFINITE);
switch (dwRes) {
case WAIT_OBJECT_0:
break;
case WAIT_OBJECT_0 + 1:
case WAIT_TIMEOUT:
return 0;
default:
fprintf(stderr, "awaitRequests: unexpected wait return code %lu\n", dwRes); fflush(stderr);
return 0;
}
} else {
return 0; /* cannot happen */
}
goto start;
} else {
int i;
StgTSO *tso, *prev;
for (i=0; i < completed_hw; i++) {
/* For each of the completed requests, match up their Ids
* with those of the threads on the blocked_queue. If the
* thread that made the IO request has been subsequently
* killed (and removed from blocked_queue), no match will
* be found for that request Id.
*
* i.e., killing a Haskell thread doesn't attempt to cancel
* the IO request it is blocked on.
*
*/
tso->block_info.async_result->len = completedTable[i].len;
tso->block_info.async_result->errCode = completedTable[i].errCode;
/* Drop the matched TSO from blocked_queue */
if ( prev == NULL ) {
blocked_queue_hd = tso->link;
if (blocked_queue_tl == tso) {
blocked_queue_tl = END_TSO_QUEUE;
unsigned int rID = completedTable[i].reqID;
prev = NULL;
prev = NULL;
for(tso = blocked_queue_hd ; tso != END_TSO_QUEUE; prev = tso, tso = tso->link) {
switch(tso->why_blocked) {
case BlockedOnRead:
case BlockedOnWrite:
case BlockedOnDoProc:
if (tso->block_info.async_result->reqID == rID) {
/* Found the thread blocked waiting on request; stodgily fill
* in its result block.
*/
tso->block_info.async_result->len = completedTable[i].len;
tso->block_info.async_result->errCode = completedTable[i].errCode;
/* Drop the matched TSO from blocked_queue */
if (prev) {
prev->link = tso->link;
} else {
blocked_queue_hd = tso->link;
}
if (blocked_queue_tl == tso) {
blocked_queue_tl = prev;
}
/* Terminates the run queue + this inner for-loop. */
tso->link = END_TSO_QUEUE;
tso->why_blocked = NotBlocked;
PUSH_ON_RUN_QUEUE(tso);
break;
}
break;
default:
if (tso->why_blocked != NotBlocked) {
barf("awaitRequests: odd thread state");
}
break;
}
} else {
prev->link = tso->link;
if (blocked_queue_tl == tso) {
blocked_queue_tl = END_TSO_QUEUE;
}
}
/* Terminates the run queue + this inner for-loop. */
tso->link = END_TSO_QUEUE;
tso->why_blocked = NotBlocked;
PUSH_ON_RUN_QUEUE(tso);
break;
}
break;
default:
if (tso->why_blocked != NotBlocked) {
barf("awaitRequests: odd thread state");
}
break;
}
}
completed_hw = 0;
ResetEvent(completed_req_event);
LeaveCriticalSection(&queue_lock);
return 1;
}
completed_hw = 0;
ResetEvent(completed_req_event);
LeaveCriticalSection(&queue_lock);
return 1;
}
}
/*
* Function: abandonRequestWait()
*
* Wake up a thread that's blocked waiting for new IO requests
* to complete (via awaitRequests().)
*/
void
abandonRequestWait()
{
/* the event is auto-reset, but in case there's no thread
* already waiting on the event, we want to return it to
* a non-signalled state.
*/
PulseEvent(abandon_req_wait);
/* the event is auto-reset, but in case there's no thread
* already waiting on the event, we want to return it to
* a non-signalled state.
*/
PulseEvent(abandon_req_wait);
}
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment