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8265028: JDWP debug agent thread lookup can be made faster

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Reviewed-by: sspitsyn, amenkov
This commit is contained in:
Chris Plummer 2021-04-19 21:15:14 +00:00
parent 713483c77d
commit e0fd5fc069
1 changed files with 20 additions and 22 deletions
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42
src/jdk.jdwp.agent/share/native/libjdwp/threadControl.c
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@ -179,8 +179,8 @@ setThreadLocalStorage(jthread thread, ThreadNode *node)
error = JVMTI_FUNC_PTR(gdata->jvmti,SetThreadLocalStorage)
(gdata->jvmti, thread, (void*)node);
if ( error == JVMTI_ERROR_THREAD_NOT_ALIVE ) {
/* Just return, thread hasn't started yet */
if ( error == JVMTI_ERROR_THREAD_NOT_ALIVE && node == NULL) {
/* Just return. This can happen when clearing the TLS. */
return;
} else if ( error != JVMTI_ERROR_NONE ) {
/* The jthread object must be valid, so this must be a fatal error */
@ -244,25 +244,17 @@ findThread(ThreadList *list, jthread thread)
/* Get thread local storage for quick thread -> node access */
node = getThreadLocalStorage(thread);
/* In some rare cases we might get NULL, so we check the list manually for
* any threads that we could match.
*/
if ( node == NULL ) {
JNIEnv *env;
env = getEnv();
if ( list != NULL ) {
node = nonTlsSearch(env, list, thread);
} else {
node = nonTlsSearch(env, &runningThreads, thread);
if ( node == NULL ) {
node = nonTlsSearch(env, &otherThreads, thread);
}
}
if ( node != NULL ) {
/* Here we make another attempt to set TLS, it's ok if this fails */
setThreadLocalStorage(thread, (void*)node);
/*
* If the thread was not yet started when the ThreadNode was created, then it
* got added to the otherThreads list and its thread local storage was not set.
* Search for it in the otherThreads list.
*/
if ( list == NULL || list == &otherThreads ) {
node = nonTlsSearch(getEnv(), &otherThreads, thread);
}
/* A thread with no TLS should never be in the runningThreads list. */
JDI_ASSERT(!nonTlsSearch(getEnv(), &runningThreads, thread));
}
/* If a list is supplied, only return ones in this list */
@ -380,10 +372,14 @@ insertThread(JNIEnv *env, ThreadList *list, jthread thread)
#endif
/* Set thread local storage for quick thread -> node access.
* Some threads may not be in a state that allows setting of TLS,
* which is ok, see findThread, it deals with threads without TLS set.
* Threads that are not yet started do not allow setting of TLS. These
* threads go on the otherThreads list and have their TLS set
* when moved to the runningThreads list. findThread() knows to look
* on otherThreads when the TLS lookup fails.
*/
setThreadLocalStorage(node->thread, (void*)node);
if (list != &otherThreads) {
setThreadLocalStorage(node->thread, (void*)node);
}
}
return node;
@ -2111,6 +2107,8 @@ threadControl_onEventHandlerEntry(jbyte sessionID, EventInfo *evinfo, jobject cu
node = findThread(&otherThreads, thread);
if (node != NULL) {
moveNode(&otherThreads, &runningThreads, node);
/* Now that we know the thread has started, we can set its TLS.*/
setThreadLocalStorage(thread, (void*)node);
} else {
/*
* Get a thread node for the reporting thread. For thread start