From ce85e03620f64ce7e4cd0598f2e93090f52a9e99 Mon Sep 17 00:00:00 2001
From: Dmitry Vyukov <dvyukov@google.com>
Date: Tue, 19 Mar 2013 12:25:48 +0000
Subject: tsan: flush dead thread info earlier (when another thread is finished
 rather than new thread is created)

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@177394 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/sanitizer_common/sanitizer_thread_registry.cc | 51 ++++++++++++++---------
 1 file changed, 32 insertions(+), 19 deletions(-)

(limited to 'lib/sanitizer_common/sanitizer_thread_registry.cc')

diff --git a/lib/sanitizer_common/sanitizer_thread_registry.cc b/lib/sanitizer_common/sanitizer_thread_registry.cc
index 3d246feee..5b3dacc56 100644
--- a/lib/sanitizer_common/sanitizer_thread_registry.cc
+++ b/lib/sanitizer_common/sanitizer_thread_registry.cc
@@ -77,11 +77,11 @@ void ThreadContextBase::SetCreated(uptr _user_id, u64 _unique_id,
   OnCreated(arg);
 }
 
-void ThreadContextBase::Reset(void *arg) {
+void ThreadContextBase::Reset() {
   status = ThreadStatusInvalid;
   reuse_count++;
   SetName(0);
-  OnReset(arg);
+  OnReset();
 }
 
 // ThreadRegistry implementation.
@@ -102,6 +102,7 @@ ThreadRegistry::ThreadRegistry(ThreadContextFactory factory, u32 max_threads,
   threads_ = (ThreadContextBase **)MmapOrDie(max_threads_ * sizeof(threads_[0]),
                                              "ThreadRegistry");
   dead_threads_.clear();
+  invalid_threads_.clear();
 }
 
 void ThreadRegistry::GetNumberOfThreads(uptr *total, uptr *running,
@@ -121,25 +122,18 @@ u32 ThreadRegistry::CreateThread(uptr user_id, bool detached, u32 parent_tid,
                                  void *arg) {
   BlockingMutexLock l(&mtx_);
   u32 tid = kUnknownTid;
-  ThreadContextBase *tctx = 0;
-  if (dead_threads_.size() > thread_quarantine_size_ ||
-      n_contexts_ >= max_threads_) {
-    // Reusing old thread descriptor and tid.
-    if (dead_threads_.size() == 0) {
-      Report("%s: Thread limit (%u threads) exceeded. Dying.\n",
-             SanitizerToolName, max_threads_);
-      Die();
-    }
-    tctx = dead_threads_.front();
-    dead_threads_.pop_front();
-    CHECK_EQ(ThreadStatusDead, tctx->status);
-    tctx->Reset(arg);
+  ThreadContextBase *tctx = QuarantinePop();
+  if (tctx) {
     tid = tctx->tid;
-  } else {
+  } else if (n_contexts_ < max_threads_) {
     // Allocate new thread context and tid.
     tid = n_contexts_++;
     tctx = context_factory_(tid);
     threads_[tid] = tctx;
+  } else {
+    Report("%s: Thread limit (%u threads) exceeded. Dying.\n",
+           SanitizerToolName, max_threads_);
+    Die();
   }
   CHECK_NE(tctx, 0);
   CHECK_NE(tid, kUnknownTid);
@@ -207,7 +201,7 @@ void ThreadRegistry::DetachThread(u32 tid) {
   }
   if (tctx->status == ThreadStatusFinished) {
     tctx->SetDead();
-    dead_threads_.push_back(tctx);
+    QuarantinePush(tctx);
   } else {
     tctx->detached = true;
   }
@@ -223,7 +217,7 @@ void ThreadRegistry::JoinThread(u32 tid, void *arg) {
     return;
   }
   tctx->SetJoined(arg);
-  dead_threads_.push_back(tctx);
+  QuarantinePush(tctx);
 }
 
 void ThreadRegistry::FinishThread(u32 tid) {
@@ -239,7 +233,7 @@ void ThreadRegistry::FinishThread(u32 tid) {
   tctx->SetFinished();
   if (tctx->detached) {
     tctx->SetDead();
-    dead_threads_.push_back(tctx);
+    QuarantinePush(tctx);
   }
 }
 
@@ -253,4 +247,23 @@ void ThreadRegistry::StartThread(u32 tid, uptr os_id, void *arg) {
   tctx->SetStarted(os_id, arg);
 }
 
+void ThreadRegistry::QuarantinePush(ThreadContextBase *tctx) {
+  dead_threads_.push_back(tctx);
+  if (dead_threads_.size() <= thread_quarantine_size_)
+    return;
+  tctx = dead_threads_.front();
+  dead_threads_.pop_front();
+  CHECK_EQ(tctx->status, ThreadStatusDead);
+  tctx->Reset();
+  invalid_threads_.push_back(tctx);
+}
+
+ThreadContextBase *ThreadRegistry::QuarantinePop() {
+  if (invalid_threads_.size() == 0)
+    return 0;
+  ThreadContextBase *tctx = invalid_threads_.front();
+  invalid_threads_.pop_front();
+  return tctx;
+}
+
 }  // namespace __sanitizer
-- 
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