Diff
Modified: releases/WebKitGTK/webkit-2.14/Source/bmalloc/ChangeLog (205599 => 205600)
--- releases/WebKitGTK/webkit-2.14/Source/bmalloc/ChangeLog 2016-09-08 07:50:43 UTC (rev 205599)
+++ releases/WebKitGTK/webkit-2.14/Source/bmalloc/ChangeLog 2016-09-08 07:56:05 UTC (rev 205600)
@@ -1,3 +1,26 @@
+2016-08-30 Geoffrey Garen <[email protected]>
+
+ bmalloc: speed up the lock slow path
+ https://bugs.webkit.org/show_bug.cgi?id=161058
+
+ Unreviewed roll-in - with regression fixed.
+
+ Revert to using yield() instead of swtch() because very low priority
+ background tasks can cause priority inversion and deadlock. In the
+ network process, that happened with com.apple.WebKit.Cache.Storage.serialBackground.
+
+ Still a big speedup on MallocBench.
+
+ * bmalloc.xcodeproj/project.pbxproj:
+ * bmalloc/ScopeExit.h: Added.
+ (bmalloc::ScopeExit::ScopeExit):
+ (bmalloc::ScopeExit::~ScopeExit):
+ (bmalloc::makeScopeExit):
+ * bmalloc/StaticMutex.cpp:
+ (bmalloc::StaticMutex::lockSlowCase):
+ * bmalloc/StaticMutex.h:
+ (bmalloc::StaticMutex::init):
+
2016-08-26 Geoffrey Garen <[email protected]>
Unreviewed build fix.
Copied: releases/WebKitGTK/webkit-2.14/Source/bmalloc/bmalloc/ScopeExit.h (from rev 205599, releases/WebKitGTK/webkit-2.14/Source/bmalloc/bmalloc/StaticMutex.cpp) (0 => 205600)
--- releases/WebKitGTK/webkit-2.14/Source/bmalloc/bmalloc/ScopeExit.h (rev 0)
+++ releases/WebKitGTK/webkit-2.14/Source/bmalloc/bmalloc/ScopeExit.h 2016-09-08 07:56:05 UTC (rev 205600)
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2016 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <type_traits>
+#include <utility>
+
+namespace bmalloc {
+
+template<typename ExitFunction>
+class ScopeExit {
+public:
+ explicit ScopeExit(ExitFunction&& exitFunction)
+ : m_exitFunction(exitFunction)
+ {
+ }
+
+ ~ScopeExit()
+ {
+ m_exitFunction();
+ }
+
+private:
+ ExitFunction m_exitFunction;
+};
+
+template<typename ExitFunction>
+ScopeExit<ExitFunction> makeScopeExit(ExitFunction&& exitFunction)
+{
+ return ScopeExit<ExitFunction>(std::forward<ExitFunction>(exitFunction));
+}
+
+} // namespace bmalloc
Modified: releases/WebKitGTK/webkit-2.14/Source/bmalloc/bmalloc/StaticMutex.cpp (205599 => 205600)
--- releases/WebKitGTK/webkit-2.14/Source/bmalloc/bmalloc/StaticMutex.cpp 2016-09-08 07:50:43 UTC (rev 205599)
+++ releases/WebKitGTK/webkit-2.14/Source/bmalloc/bmalloc/StaticMutex.cpp 2016-09-08 07:56:05 UTC (rev 205600)
@@ -23,6 +23,7 @@
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
+#include "ScopeExit.h"
#include "StaticMutex.h"
#include <thread>
@@ -30,6 +31,21 @@
void StaticMutex::lockSlowCase()
{
+ // The longest critical section in bmalloc is much shorter than the
+ // time it takes to make a system call to yield to the OS scheduler.
+ // So, we try again a lot before we yield.
+ static const size_t aLot = 256;
+
+ if (!m_isSpinning.test_and_set()) {
+ auto clear = makeScopeExit([&] { m_isSpinning.clear(); });
+
+ for (size_t i = 0; i < aLot; ++i) {
+ if (try_lock())
+ return;
+ }
+ }
+
+ // Avoid spinning pathologically.
while (!try_lock())
std::this_thread::yield();
}
Modified: releases/WebKitGTK/webkit-2.14/Source/bmalloc/bmalloc/StaticMutex.h (205599 => 205600)
--- releases/WebKitGTK/webkit-2.14/Source/bmalloc/bmalloc/StaticMutex.h 2016-09-08 07:50:43 UTC (rev 205599)
+++ releases/WebKitGTK/webkit-2.14/Source/bmalloc/bmalloc/StaticMutex.h 2016-09-08 07:56:05 UTC (rev 205600)
@@ -52,6 +52,7 @@
void lockSlowCase();
std::atomic_flag m_flag;
+ std::atomic_flag m_isSpinning;
};
static inline void sleep(
@@ -78,6 +79,7 @@
inline void StaticMutex::init()
{
m_flag.clear();
+ m_isSpinning.clear();
}
inline bool StaticMutex::try_lock()
Modified: releases/WebKitGTK/webkit-2.14/Source/bmalloc/bmalloc.xcodeproj/project.pbxproj (205599 => 205600)
--- releases/WebKitGTK/webkit-2.14/Source/bmalloc/bmalloc.xcodeproj/project.pbxproj 2016-09-08 07:50:43 UTC (rev 205599)
+++ releases/WebKitGTK/webkit-2.14/Source/bmalloc/bmalloc.xcodeproj/project.pbxproj 2016-09-08 07:56:05 UTC (rev 205600)
@@ -24,6 +24,7 @@
147DC6E31CA5B70B00724E8D /* Chunk.h in Headers */ = {isa = PBXBuildFile; fileRef = 147DC6E21CA5B70B00724E8D /* Chunk.h */; settings = {ATTRIBUTES = (Private, ); }; };
14895D911A3A319C0006235D /* Environment.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 14895D8F1A3A319C0006235D /* Environment.cpp */; };
14895D921A3A319C0006235D /* Environment.h in Headers */ = {isa = PBXBuildFile; fileRef = 14895D901A3A319C0006235D /* Environment.h */; settings = {ATTRIBUTES = (Private, ); }; };
+ 148EFAE81D6B953B008E721E /* ScopeExit.h in Headers */ = {isa = PBXBuildFile; fileRef = 148EFAE61D6B953B008E721E /* ScopeExit.h */; };
14C8992B1CC485E70027A057 /* Map.h in Headers */ = {isa = PBXBuildFile; fileRef = 14C8992A1CC485E70027A057 /* Map.h */; settings = {ATTRIBUTES = (Private, ); }; };
14C8992D1CC578330027A057 /* LargeRange.h in Headers */ = {isa = PBXBuildFile; fileRef = 14C8992C1CC578330027A057 /* LargeRange.h */; settings = {ATTRIBUTES = (Private, ); }; };
14C919C918FCC59F0028DB43 /* BPlatform.h in Headers */ = {isa = PBXBuildFile; fileRef = 14C919C818FCC59F0028DB43 /* BPlatform.h */; settings = {ATTRIBUTES = (Private, ); }; };
@@ -110,6 +111,7 @@
1485656018A43DBA00ED6942 /* ObjectType.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ObjectType.h; path = bmalloc/ObjectType.h; sourceTree = "<group>"; };
14895D8F1A3A319C0006235D /* Environment.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = Environment.cpp; path = bmalloc/Environment.cpp; sourceTree = "<group>"; };
14895D901A3A319C0006235D /* Environment.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = Environment.h; path = bmalloc/Environment.h; sourceTree = "<group>"; };
+ 148EFAE61D6B953B008E721E /* ScopeExit.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ScopeExit.h; path = bmalloc/ScopeExit.h; sourceTree = "<group>"; };
14B650C518F39F4800751968 /* Base.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; path = Base.xcconfig; sourceTree = "<group>"; };
14B650C618F39F4800751968 /* bmalloc.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; path = bmalloc.xcconfig; sourceTree = "<group>"; };
14B650C718F39F4800751968 /* DebugRelease.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; path = DebugRelease.xcconfig; sourceTree = "<group>"; };
@@ -262,6 +264,7 @@
14446A0717A61FA400F9EA1D /* PerProcess.h */,
144469FD17A61F1F00F9EA1D /* PerThread.h */,
145F6878179E3A4400D65598 /* Range.h */,
+ 148EFAE61D6B953B008E721E /* ScopeExit.h */,
143CB81A19022BC900B16A45 /* StaticMutex.cpp */,
143CB81B19022BC900B16A45 /* StaticMutex.h */,
1417F64F18B7280C0076FA3F /* Syscall.h */,
@@ -316,6 +319,7 @@
14895D921A3A319C0006235D /* Environment.h in Headers */,
1400274A18F89C2300115C97 /* VMHeap.h in Headers */,
1400274918F89C1300115C97 /* Heap.h in Headers */,
+ 148EFAE81D6B953B008E721E /* ScopeExit.h in Headers */,
140FA00319CE429C00FFD3C8 /* BumpRange.h in Headers */,
4426E2811C838EE0008EB042 /* Logging.h in Headers */,
14DD78C518F48D7500950702 /* Algorithm.h in Headers */,
