From: Amos Jeffries <squid3@treenet.co.nz>
Date: Tue, 2 Jun 2015 15:28:56 +0000 (-0700)
Subject: Convert Ipc::Queue to std::atomic
X-Git-Tag: merge-candidate-3-v1~72^2~3
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6c6a656afd32a3b3293ec87ce7ad42045d83c610;p=thirdparty%2Fsquid.git

Convert Ipc::Queue to std::atomic
---

diff --git a/src/DiskIO/IpcIo/IpcIoFile.cc b/src/DiskIO/IpcIo/IpcIoFile.cc
index 4b650ecd75..0297e06e63 100644
--- a/src/DiskIO/IpcIo/IpcIoFile.cc
+++ b/src/DiskIO/IpcIo/IpcIoFile.cc
@@ -113,8 +113,7 @@ IpcIoFile::open(int flags, mode_t mode, RefCount<IORequestor> callback)
             IpcIoFiles.insert(std::make_pair(diskId, this)).second;
         Must(inserted);
 
-        queue->localRateLimit() =
-            static_cast<Ipc::QueueReader::Rate::Value>(config.ioRate);
+        queue->localRateLimit().store(config.ioRate);
 
         Ipc::HereIamMessage ann(Ipc::StrandCoord(KidIdentifier, getpid()));
         ann.strand.tag = dbName;
@@ -396,7 +395,7 @@ IpcIoFile::canWait() const
     const int oldestWait = tvSubMsec(oldestIo.start, current_time);
 
     int rateWait = -1; // time in millisecons
-    const Ipc::QueueReader::Rate::Value ioRate = queue->rateLimit(diskId);
+    const int ioRate = queue->rateLimit(diskId).load();
     if (ioRate > 0) {
         // if there are N requests pending, the new one will wait at
         // least N/max-swap-rate seconds
@@ -750,7 +749,7 @@ IpcIoFile::DiskerHandleMoreRequests(void *source)
 bool
 IpcIoFile::WaitBeforePop()
 {
-    const Ipc::QueueReader::Rate::Value ioRate = queue->localRateLimit();
+    const int ioRate = queue->localRateLimit().load();
     const double maxRate = ioRate/1e3; // req/ms
 
     // do we need to enforce configured I/O rate?
diff --git a/src/MemStore.cc b/src/MemStore.cc
index 47c908e867..e9142c52f3 100644
--- a/src/MemStore.cc
+++ b/src/MemStore.cc
@@ -12,6 +12,7 @@
 #include "base/RunnersRegistry.h"
 #include "CollapsedForwarding.h"
 #include "HttpReply.h"
+#include "ipc/AtomicWord.h"
 #include "ipc/mem/Page.h"
 #include "ipc/mem/Pages.h"
 #include "MemObject.h"
diff --git a/src/ipc/Queue.cc b/src/ipc/Queue.cc
index 9e24870d07..853374e4de 100644
--- a/src/ipc/Queue.cc
+++ b/src/ipc/Queue.cc
@@ -44,7 +44,7 @@ ReadersId(String id)
 
 InstanceIdDefinitions(Ipc::QueueReader, "ipcQR");
 
-Ipc::QueueReader::QueueReader(): popBlocked(1), popSignal(0),
+Ipc::QueueReader::QueueReader(): popBlocked(true), popSignal(false),
     rateLimit(0), balance(0)
 {
     debugs(54, 7, HERE << "constructed " << id);
diff --git a/src/ipc/Queue.h b/src/ipc/Queue.h
index 310ba21d15..b6128de515 100644
--- a/src/ipc/Queue.h
+++ b/src/ipc/Queue.h
@@ -11,11 +11,12 @@
 
 #include "base/InstanceId.h"
 #include "Debug.h"
-#include "ipc/AtomicWord.h"
 #include "ipc/mem/FlexibleArray.h"
 #include "ipc/mem/Pointer.h"
 #include "util.h"
 
+#include <atomic>
+
 class String;
 
 namespace Ipc
@@ -29,31 +30,31 @@ public:
     QueueReader(); // the initial state is "blocked without a signal"
 
     /// whether the reader is waiting for a notification signal
-    bool blocked() const { return popBlocked == 1; }
+    bool blocked() const { return popBlocked.load(); }
 
     /// marks the reader as blocked, waiting for a notification signal
-    void block() { popBlocked.swap_if(0, 1); }
+    void block() { popBlocked.store(true); }
 
     /// removes the block() effects
-    void unblock() { popBlocked.swap_if(1, 0); }
+    void unblock() { popBlocked.store(false); }
 
     /// if reader is blocked and not notified, marks the notification signal
     /// as sent and not received, returning true; otherwise, returns false
-    bool raiseSignal() { return blocked() && popSignal.swap_if(0,1); }
+    bool raiseSignal() { return blocked() && !popSignal.exchange(true); }
 
     /// marks sent reader notification as received (also removes pop blocking)
-    void clearSignal() { unblock(); popSignal.swap_if(1,0); }
+    void clearSignal() { unblock(); popSignal.store(false); }
 
 private:
-    Atomic::Word popBlocked; ///< whether the reader is blocked on pop()
-    Atomic::Word popSignal; ///< whether writer has sent and reader has not received notification
+    std::atomic<bool> popBlocked; ///< whether the reader is blocked on pop()
+    std::atomic<bool> popSignal; ///< whether writer has sent and reader has not received notification
 
 public:
-    typedef Atomic::Word Rate; ///< pop()s per second
+    typedef std::atomic<int> Rate; ///< pop()s per second
     Rate rateLimit; ///< pop()s per second limit if positive
 
     // we need a signed atomic type because balance may get negative
-    typedef Atomic::WordT<int> AtomicSignedMsec;
+    typedef std::atomic<int> AtomicSignedMsec;
     typedef AtomicSignedMsec Balance;
     /// how far ahead the reader is compared to a perfect read/sec event rate
     Balance balance;
@@ -118,9 +119,9 @@ private:
     unsigned int theIn; ///< input index, used only in push()
     unsigned int theOut; ///< output index, used only in pop()
 
-    Atomic::Word theSize; ///< number of items in the queue
+    std::atomic<uint32_t> theSize; ///< number of items in the queue
     const unsigned int theMaxItemSize; ///< maximum item size
-    const int theCapacity; ///< maximum number of items, i.e. theBuffer size
+    const uint32_t theCapacity; ///< maximum number of items, i.e. theBuffer size
 
     char theBuffer[];
 };