Make ObjectCacheV2 reclaim in more effecient way using C++17

alibaba · Aug 7, 2024 · 008840e · 008840e
1 parent 2dd0075
commit 008840e
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Showing 4 changed files with 27 additions and 8 deletions.
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -16,7 +16,7 @@ include(CMake/build-from-src.cmake)
 find_package(PkgConfig REQUIRED)
 
 # Options
-set(PHOTON_CXX_STANDARD "14" CACHE STRING "C++ standard")
+set(PHOTON_CXX_STANDARD "17" CACHE STRING "C++ standard")
 option(PHOTON_BUILD_TESTING "enable build testing" OFF)
 option(PHOTON_BUILD_WITH_ASAN "build with asan" OFF)
 option(PHOTON_ENABLE_URING "enable io_uring function" OFF)

diff --git a/common/enumerable.h b/common/enumerable.h
@@ -42,7 +42,7 @@ struct Enumerable
             this->obj = nullptr;
         }
         using R = typename std::result_of<decltype(&T::get)(T)>::type;
-        R operator*() { return obj ? obj->get() : nullptr; }
+        R operator*() { return obj ? obj->get() : R{}; }
         bool operator==(const iterator& rhs) const { return obj == rhs.obj; }
         bool operator!=(const iterator& rhs) const { return !(*this == rhs); }
         iterator& operator++()

diff --git a/common/objectcachev2.h b/common/objectcachev2.h
@@ -63,7 +63,7 @@ class ObjectCacheV2 {
             std::swap(r, ref);
             return r;
         }
-        std::shared_ptr<V> clear(uint64_t ts = 0) {
+        std::shared_ptr<V> reset(uint64_t ts = 0) {
             return update({nullptr}, ts);
         }
         std::shared_ptr<V> reader() { return ref; }
@@ -116,7 +116,11 @@ class ObjectCacheV2 {
         return *box;
     }
     uint64_t __expire() {
+#if __cplusplus < 201703L
         std::vector<std::shared_ptr<V>> to_release;
+#else
+        intrusive_list<Box> to_release;
+#endif
         uint64_t now = photon::now;
         uint64_t reclaim_before = photon::sat_sub(now, lifespan);
         {
@@ -132,13 +136,27 @@ class ObjectCacheV2 {
                 if (x->rc == 0) {
                     // make vector holds those shared_ptr
                     // prevent object destroy in critical zone
-                    to_release.push_back(x->clear());
+#if __cplusplus < 201703L
+                    to_release.push_back(x->reset());
                     map.erase(*x);
+#else
+                    // Here is a hacked implementation
+                    auto node = map.extract(*x);
+                    to_release.push_back(&node.value());
+                    /// node_handle should be just key&val pointer
+                    // Force make it empty can prevent destroy object
+                    // when node_handle goes to destroy
+                    memset((void*)&node, 0, sizeof(node));
+#endif
                 }
                 x = lru_list.front();
             }
         }
+#if __cplusplus < 201703L
         to_release.clear();
+#else
+        to_release.delete_all();
+#endif
         return 0;
     }
 
@@ -162,7 +180,7 @@ class ObjectCacheV2 {
 
         ~Borrow() {
             if (_recycle) {
-                _box->clear();
+                _box->reset();
             }
             _box->release();
             if (_box->rc == 0) {
@@ -228,7 +246,8 @@ class ObjectCacheV2 {
 
     ~ObjectCacheV2() {
         _timer.stop();
-        SCOPED_LOCK(maplock);
+        // Should be no other access during dtor.
+        // modify lru_list do not need a lock.
         lru_list.node = nullptr;
     }
 };
diff --git a/common/ring.cpp b/common/ring.cpp
@@ -60,7 +60,7 @@ ssize_t RingBuffer::do_read(void *buf, size_t count)
 ssize_t RingBuffer::readv(const struct iovec *iov, int iovcnt)
 {
     ssize_t size = 0;
-    scoped_lock lock(m_read_lock);
+    photon::scoped_lock lock(m_read_lock);
     for (auto& x: ptr_array(iov, iovcnt))
     {
         auto ret = do_read(x.iov_base, x.iov_len);
@@ -110,7 +110,7 @@ ssize_t RingBuffer::do_write(const void* buf, size_t count)
 ssize_t RingBuffer::writev(const struct iovec *iov, int iovcnt)
 {
     ssize_t size = 0;
-    scoped_lock lock(m_write_lock);
+    photon::scoped_lock lock(m_write_lock);
     for (auto& x: ptr_array(iov, iovcnt))
     {
         auto ret = do_write(x.iov_base, x.iov_len);