diff --git a/BUILD b/BUILD
index da9866df81aa7af5fbb74ba9aa712ea73431efdd..a375b04cb5d4347953d58409325e15bfb5b91df5 100644
--- a/BUILD
+++ b/BUILD
@@ -47,6 +47,7 @@ cc_library(
"src/core/support/env.h",
"src/core/support/file.h",
"src/core/support/murmur_hash.h",
+ "src/core/support/stack_lockfree.h",
"src/core/support/string.h",
"src/core/support/string_win32.h",
"src/core/support/thd_internal.h",
@@ -73,6 +74,7 @@ cc_library(
"src/core/support/murmur_hash.c",
"src/core/support/slice.c",
"src/core/support/slice_buffer.c",
+ "src/core/support/stack_lockfree.c",
"src/core/support/string.c",
"src/core/support/string_posix.c",
"src/core/support/string_win32.c",
@@ -873,6 +875,7 @@ objc_library(
"src/core/support/murmur_hash.c",
"src/core/support/slice.c",
"src/core/support/slice_buffer.c",
+ "src/core/support/stack_lockfree.c",
"src/core/support/string.c",
"src/core/support/string_posix.c",
"src/core/support/string_win32.c",
@@ -920,6 +923,7 @@ objc_library(
"src/core/support/env.h",
"src/core/support/file.h",
"src/core/support/murmur_hash.h",
+ "src/core/support/stack_lockfree.h",
"src/core/support/string.h",
"src/core/support/string_win32.h",
"src/core/support/thd_internal.h",
diff --git a/Makefile b/Makefile
index f1c99a909d7bf51ca89ba27a03ff6db46c1b2ed7..0b4c889fd873e8e3be5754e0bb7f38eca0a11f60 100644
--- a/Makefile
+++ b/Makefile
@@ -3100,6 +3100,7 @@ LIBGPR_SRC = \
src/core/support/murmur_hash.c \
src/core/support/slice.c \
src/core/support/slice_buffer.c \
+ src/core/support/stack_lockfree.c \
src/core/support/string.c \
src/core/support/string_posix.c \
src/core/support/string_win32.c \
diff --git a/build.json b/build.json
index 2a11275636a0ab80acd89cfde0d70c8d0ec6fc10..6b6a7866c971ef6b8396278e30d868e70f4d270c 100644
--- a/build.json
+++ b/build.json
@@ -373,6 +373,7 @@
"src/core/support/env.h",
"src/core/support/file.h",
"src/core/support/murmur_hash.h",
+ "src/core/support/stack_lockfree.h",
"src/core/support/string.h",
"src/core/support/string_win32.h",
"src/core/support/thd_internal.h"
@@ -401,6 +402,7 @@
"src/core/support/murmur_hash.c",
"src/core/support/slice.c",
"src/core/support/slice_buffer.c",
+ "src/core/support/stack_lockfree.c",
"src/core/support/string.c",
"src/core/support/string_posix.c",
"src/core/support/string_win32.c",
diff --git a/gRPC.podspec b/gRPC.podspec
index 921a4ab096fd1c8a27606373da69608276908034..2df6f5132ccd76c662c353299ccd047ea32ab334 100644
--- a/gRPC.podspec
+++ b/gRPC.podspec
@@ -64,6 +64,7 @@ Pod::Spec.new do |s|
ss.source_files = 'src/core/support/env.h',
'src/core/support/file.h',
'src/core/support/murmur_hash.h',
+ 'src/core/support/stack_lockfree.h',
'src/core/support/grpc_string.h',
'src/core/support/string_win32.h',
'src/core/support/thd_internal.h',
@@ -118,6 +119,7 @@ Pod::Spec.new do |s|
'src/core/support/murmur_hash.c',
'src/core/support/slice.c',
'src/core/support/slice_buffer.c',
+ 'src/core/support/stack_lockfree.c',
'src/core/support/string.c',
'src/core/support/string_posix.c',
'src/core/support/string_win32.c',
@@ -389,6 +391,7 @@ Pod::Spec.new do |s|
ss.private_header_files = 'src/core/support/env.h',
'src/core/support/file.h',
'src/core/support/murmur_hash.h',
+ 'src/core/support/stack_lockfree.h',
'src/core/support/string.h',
'src/core/support/string_win32.h',
'src/core/support/thd_internal.h',
diff --git a/src/core/support/stack_lockfree.c b/src/core/support/stack_lockfree.c
new file mode 100644
index 0000000000000000000000000000000000000000..4d6a75cd33469d78b271211d8de2e718b9c4ea89
--- /dev/null
+++ b/src/core/support/stack_lockfree.c
@@ -0,0 +1,130 @@
+/*
+ *
+ * Copyright 2015, Google 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:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * 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.
+ * * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "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 THE COPYRIGHT
+ * OWNER 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 "src/core/support/stack_lockfree.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include <grpc/support/port_platform.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/atm.h>
+#include <grpc/support/log.h>
+
+/* The lockfree node structure is a single architecture-level
+ word that allows for an atomic CAS to set it up. */
+struct lockfree_node_contents {
+ /* next thing to look at. Actual index for head, next index otherwise */
+ gpr_uint16 index;
+#ifdef GPR_ARCH_64
+ gpr_uint16 pad;
+ gpr_uint32 aba_ctr;
+#else
+#ifdef GPR_ARCH_32
+ gpr_uint16 aba_ctr;
+#else
+#error Unsupported bit width architecture
+#endif
+#endif
+};
+
+/* Use a union to make sure that these are in the same bits as an atm word */
+typedef union lockfree_node {
+ gpr_atm atm;
+ struct lockfree_node_contents contents;
+} lockfree_node;
+
+#define ENTRY_ALIGNMENT_BITS 3 /* make sure that entries aligned to 8-bytes */
+#define INVALID_ENTRY_INDEX ((1<<16)-1) /* reserve this entry as invalid */
+
+struct gpr_stack_lockfree {
+ lockfree_node *entries;
+ lockfree_node head; /* An atomic entry describing curr head */
+};
+
+gpr_stack_lockfree *gpr_stack_lockfree_create(int entries) {
+ gpr_stack_lockfree *stack;
+ stack = gpr_malloc(sizeof(*stack));
+ /* Since we only allocate 16 bits to represent an entry number,
+ * make sure that we are within the desired range */
+ /* Reserve the highest entry number as a dummy */
+ GPR_ASSERT(entries < INVALID_ENTRY_INDEX);
+ stack->entries = gpr_malloc_aligned(entries * sizeof(stack->entries[0]),
+ ENTRY_ALIGNMENT_BITS);
+ /* Clear out all entries */
+ memset(stack->entries, 0, entries * sizeof(stack->entries[0]));
+
+ /* Point the head at reserved dummy entry */
+ stack->head.contents.index = INVALID_ENTRY_INDEX;
+ return stack;
+}
+
+void gpr_stack_lockfree_destroy(gpr_stack_lockfree *stack) {
+ gpr_free_aligned(stack->entries);
+ gpr_free(stack);
+}
+
+void gpr_stack_lockfree_push(gpr_stack_lockfree *stack, int entry) {
+ lockfree_node head;
+ lockfree_node newhead;
+
+ /* First fill in the entry's index and aba ctr for new head */
+ newhead.contents.index = (gpr_uint16)entry;
+ /* Also post-increment the aba_ctr */
+ newhead.contents.aba_ctr = stack->entries[entry].contents.aba_ctr++;
+
+ do {
+ /* Atomically get the existing head value for use */
+ head.atm = gpr_atm_no_barrier_load(&(stack->head.atm));
+ /* Point to it */
+ stack->entries[entry].contents.index = head.contents.index;
+ } while (!gpr_atm_rel_cas(&(stack->head.atm),
+ head.atm, newhead.atm));
+ /* Use rel_cas above to make sure that entry index is set properly */
+}
+
+int gpr_stack_lockfree_pop(gpr_stack_lockfree *stack) {
+ lockfree_node head;
+ lockfree_node newhead;
+ do {
+ head.atm = gpr_atm_acq_load(&(stack->head.atm));
+ if (head.contents.index == INVALID_ENTRY_INDEX) {
+ return -1;
+ }
+ newhead.contents.index = stack->entries[head.contents.index].contents.index;
+
+ } while (!gpr_atm_no_barrier_cas(&(stack->head.atm),
+ head.atm,
+ newhead.atm));
+ return newhead.contents.index;
+}
diff --git a/src/core/support/stack_lockfree.h b/src/core/support/stack_lockfree.h
new file mode 100644
index 0000000000000000000000000000000000000000..7919ef38ccdc57c9ff26dc05565012b6b932742a
--- /dev/null
+++ b/src/core/support/stack_lockfree.h
@@ -0,0 +1,50 @@
+/*
+ *
+ * Copyright 2015, Google 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:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * 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.
+ * * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "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 THE COPYRIGHT
+ * OWNER 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.
+ *
+ */
+
+#ifndef GRPC_INTERNAL_CORE_SUPPORT_STACK_LOCKFREE_H
+#define GRPC_INTERNAL_CORE_SUPPORT_STACK_LOCKFREE_H
+
+typedef struct gpr_stack_lockfree gpr_stack_lockfree;
+
+/* This stack must specify the maximum number of entries to track.
+ The current implementation only allows up to 65534 entries */
+gpr_stack_lockfree *gpr_stack_lockfree_create(int entries);
+void gpr_stack_lockfree_destroy(gpr_stack_lockfree *);
+
+/* Pass in a valid entry number for the next stack entry */
+void gpr_stack_lockfree_push(gpr_stack_lockfree *, int entry);
+
+/* Returns -1 on empty or the actual entry number */
+int gpr_stack_lockfree_pop(gpr_stack_lockfree *);
+
+#endif /* GRPC_INTERNAL_CORE_SUPPORT_STACK_LOCKFREE_H */
diff --git a/tools/doxygen/Doxyfile.core.internal b/tools/doxygen/Doxyfile.core.internal
index ac411e3c02dc3d9a1d7d8d3e86a141bd274de9df..3e57dbdff1a24a1ece208b8ddc0a9801e8f12c47 100644
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@@ -1044,6 +1044,7 @@ include/grpc/support/useful.h \
src/core/support/env.h \
src/core/support/file.h \
src/core/support/murmur_hash.h \
+src/core/support/stack_lockfree.h \
src/core/support/string.h \
src/core/support/string_win32.h \
src/core/support/thd_internal.h \
@@ -1070,6 +1071,7 @@ src/core/support/log_win32.c \
src/core/support/murmur_hash.c \
src/core/support/slice.c \
src/core/support/slice_buffer.c \
+src/core/support/stack_lockfree.c \
src/core/support/string.c \
src/core/support/string_posix.c \
src/core/support/string_win32.c \
diff --git a/tools/run_tests/sources_and_headers.json b/tools/run_tests/sources_and_headers.json
index 3f13b7b9adb0f026b500785765c950f4f03fa2ed..9297a35d9aeac51f87d002ba20ac2e885dd390c8 100644
--- a/tools/run_tests/sources_and_headers.json
+++ b/tools/run_tests/sources_and_headers.json
@@ -8595,6 +8595,7 @@
"src/core/support/env.h",
"src/core/support/file.h",
"src/core/support/murmur_hash.h",
+ "src/core/support/stack_lockfree.h",
"src/core/support/string.h",
"src/core/support/string_win32.h",
"src/core/support/thd_internal.h"
@@ -8656,6 +8657,8 @@
"src/core/support/murmur_hash.h",
"src/core/support/slice.c",
"src/core/support/slice_buffer.c",
+ "src/core/support/stack_lockfree.c",
+ "src/core/support/stack_lockfree.h",
"src/core/support/string.c",
"src/core/support/string.h",
"src/core/support/string_posix.c",
diff --git a/vsprojects/gpr/gpr.vcxproj b/vsprojects/gpr/gpr.vcxproj
index 3e6bb2036e5ad2a70b0eb70c78b833379f2a3f86..32a08a232146d604a9f1c3ba24e02263ff6a2748 100644
--- a/vsprojects/gpr/gpr.vcxproj
+++ b/vsprojects/gpr/gpr.vcxproj
@@ -179,6 +179,7 @@
<ClInclude Include="..\..\src\core\support\env.h" />
<ClInclude Include="..\..\src\core\support\file.h" />
<ClInclude Include="..\..\src\core\support\murmur_hash.h" />
+ <ClInclude Include="..\..\src\core\support\stack_lockfree.h" />
<ClInclude Include="..\..\src\core\support\string.h" />
<ClInclude Include="..\..\src\core\support\string_win32.h" />
<ClInclude Include="..\..\src\core\support\thd_internal.h" />
@@ -230,6 +231,8 @@
</ClCompile>
<ClCompile Include="..\..\src\core\support\slice_buffer.c">
</ClCompile>
+ <ClCompile Include="..\..\src\core\support\stack_lockfree.c">
+ </ClCompile>
<ClCompile Include="..\..\src\core\support\string.c">
</ClCompile>
<ClCompile Include="..\..\src\core\support\string_posix.c">
diff --git a/vsprojects/gpr/gpr.vcxproj.filters b/vsprojects/gpr/gpr.vcxproj.filters
index a270902236c9620c752c9ffd25e78a9cb2c35857..ace549fa45e17fa227e6da841c2da552f5748320 100644
--- a/vsprojects/gpr/gpr.vcxproj.filters
+++ b/vsprojects/gpr/gpr.vcxproj.filters
@@ -70,6 +70,9 @@
<ClCompile Include="..\..\src\core\support\slice_buffer.c">
<Filter>src\core\support</Filter>
</ClCompile>
+ <ClCompile Include="..\..\src\core\support\stack_lockfree.c">
+ <Filter>src\core\support</Filter>
+ </ClCompile>
<ClCompile Include="..\..\src\core\support\string.c">
<Filter>src\core\support</Filter>
</ClCompile>
@@ -209,6 +212,9 @@
<ClInclude Include="..\..\src\core\support\murmur_hash.h">
<Filter>src\core\support</Filter>
</ClInclude>
+ <ClInclude Include="..\..\src\core\support\stack_lockfree.h">
+ <Filter>src\core\support</Filter>
+ </ClInclude>
<ClInclude Include="..\..\src\core\support\string.h">
<Filter>src\core\support</Filter>
</ClInclude>