[Lldb-commits] [lldb] [lldb-dap] Implement a MemoryMonitor for macOS & Linux (PR #129332)
Jonas Devlieghere via lldb-commits
lldb-commits at lists.llvm.org
Tue Mar 4 22:44:10 PST 2025
https://github.com/JDevlieghere updated https://github.com/llvm/llvm-project/pull/129332
>From c63350db79ac6bcc6f180cc84a37e829d1c8b2a8 Mon Sep 17 00:00:00 2001
From: Jonas Devlieghere <jonas at devlieghere.com>
Date: Fri, 28 Feb 2025 14:54:42 -0600
Subject: [PATCH 1/5] [lldb-dap] Implement a MemoryMonitor for macOS & Linux
This implements a memory monitor for macOS & Linux, and registers a
callback that invokes SBDebugger::MemoryPressureDetected() when a low
memory event is detected.
---
lldb/tools/lldb-dap/CMakeLists.txt | 1 +
lldb/tools/lldb-dap/MemoryMonitor.cpp | 114 ++++++++++++++++++++++++++
lldb/tools/lldb-dap/MemoryMonitor.h | 41 +++++++++
lldb/tools/lldb-dap/lldb-dap.cpp | 17 +++-
4 files changed, 171 insertions(+), 2 deletions(-)
create mode 100644 lldb/tools/lldb-dap/MemoryMonitor.cpp
create mode 100644 lldb/tools/lldb-dap/MemoryMonitor.h
diff --git a/lldb/tools/lldb-dap/CMakeLists.txt b/lldb/tools/lldb-dap/CMakeLists.txt
index 8b3c520ec4360..8db377e31c3c6 100644
--- a/lldb/tools/lldb-dap/CMakeLists.txt
+++ b/lldb/tools/lldb-dap/CMakeLists.txt
@@ -36,6 +36,7 @@ add_lldb_tool(lldb-dap
RunInTerminal.cpp
SourceBreakpoint.cpp
Watchpoint.cpp
+ MemoryMonitor.cpp
Handler/ResponseHandler.cpp
Handler/AttachRequestHandler.cpp
diff --git a/lldb/tools/lldb-dap/MemoryMonitor.cpp b/lldb/tools/lldb-dap/MemoryMonitor.cpp
new file mode 100644
index 0000000000000..da3da42fe9b0f
--- /dev/null
+++ b/lldb/tools/lldb-dap/MemoryMonitor.cpp
@@ -0,0 +1,114 @@
+//===-- MemoryMonitor.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "MemoryMonitor.h"
+#include "llvm/ADT/ScopeExit.h"
+#include <atomic>
+#include <cstdio>
+#include <cstring>
+#include <thread>
+
+#if defined(__APPLE__)
+#include <dispatch/dispatch.h>
+#endif
+
+#if defined(__linux__)
+#include <fcntl.h>
+#include <poll.h>
+#include <unistd.h>
+#endif
+
+using namespace lldb_dap;
+
+#if defined(__APPLE__)
+class MemoryMonitorDarwin : public MemoryMonitor {
+ using MemoryMonitor::MemoryMonitor;
+ void Start() override {
+ m_memory_pressure_source = dispatch_source_create(
+ DISPATCH_SOURCE_TYPE_MEMORYPRESSURE,
+ 0, // system-wide monitoring
+ DISPATCH_MEMORYPRESSURE_WARN | DISPATCH_MEMORYPRESSURE_CRITICAL,
+ dispatch_get_main_queue());
+
+ dispatch_source_set_event_handler(m_memory_pressure_source, ^{
+ dispatch_source_memorypressure_flags_t pressureLevel =
+ dispatch_source_get_data(m_memory_pressure_source);
+ if (pressureLevel &
+ (DISPATCH_MEMORYPRESSURE_WARN | DISPATCH_MEMORYPRESSURE_CRITICAL)) {
+ m_callback();
+ }
+ });
+ }
+
+ void Stop() override { dispatch_source_cancel(m_memory_pressure_source); }
+
+private:
+ dispatch_source_t m_memory_pressure_source;
+};
+#endif
+
+#if defined(__linux__)
+static void MonitorThread(std::atomic<bool> &done,
+ MemoryMonitor::Callback callback) {
+ struct pollfd fds;
+ fds.fd = open("/proc/pressure/memory", O_RDWR | O_NONBLOCK);
+ if (fds.fd < 0)
+ return;
+ fds.events = POLLPRI;
+
+ auto cleanup = llvm::make_scope_exit([&]() { close(fds.fd); });
+
+ // Detect a 50ms stall in a 2 second time window.
+ const char trig[] = "some 50000 2000000";
+ if (write(fds.fd, trig, strlen(trig) + 1) < 0)
+ return;
+
+ while (!done) {
+ int n = poll(&fds, 1, 1000);
+ if (n > 0) {
+ if (fds.revents & POLLERR)
+ return;
+ if (fds.revents & POLLPRI)
+ callback();
+ }
+ }
+}
+
+class MemoryMonitorLinux : public MemoryMonitor {
+public:
+ using MemoryMonitor::MemoryMonitor;
+
+ void Start() override {
+ m_memory_pressure_thread =
+ std::thread(MonitorThread, std::ref(m_done), m_callback);
+ }
+
+ void Stop() override {
+ if (m_memory_pressure_thread.joinable()) {
+ m_done = true;
+ m_memory_pressure_thread.join();
+ }
+ }
+
+private:
+ std::atomic<bool> m_done = false;
+ std::thread m_memory_pressure_thread;
+};
+#endif
+
+std::unique_ptr<MemoryMonitor> MemoryMonitor::Create(Callback callback) {
+#if defined(__APPLE__)
+ return std::make_unique<MemoryMonitorDarwin>(callback);
+#endif
+
+#if defined(__linux__)
+ return std::make_unique<MemoryMonitorLinux>(callback);
+#endif
+
+ return nullptr;
+}
diff --git a/lldb/tools/lldb-dap/MemoryMonitor.h b/lldb/tools/lldb-dap/MemoryMonitor.h
new file mode 100644
index 0000000000000..e07c3bde9e85c
--- /dev/null
+++ b/lldb/tools/lldb-dap/MemoryMonitor.h
@@ -0,0 +1,41 @@
+//===-- MemoryMonitor.h ---------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_TOOLS_LLDB_DAP_WATCHPOINT_H
+#define LLDB_TOOLS_LLDB_DAP_WATCHPOINT_H
+
+#include <functional>
+#include <memory>
+
+namespace lldb_dap {
+
+class MemoryMonitor {
+public:
+ using Callback = std::function<void()>;
+
+ MemoryMonitor(Callback callback) : m_callback(callback) {}
+ virtual ~MemoryMonitor() = default;
+
+ /// MemoryMonitor is not copyable.
+ /// @{
+ MemoryMonitor(const MemoryMonitor &) = delete;
+ MemoryMonitor &operator=(const MemoryMonitor &) = delete;
+ /// @}
+
+ static std::unique_ptr<MemoryMonitor> Create(Callback callback);
+
+ virtual void Start() = 0;
+ virtual void Stop() = 0;
+
+protected:
+ Callback m_callback;
+};
+
+} // namespace lldb_dap
+
+#endif
diff --git a/lldb/tools/lldb-dap/lldb-dap.cpp b/lldb/tools/lldb-dap/lldb-dap.cpp
index d005eccfae903..41405df548da2 100644
--- a/lldb/tools/lldb-dap/lldb-dap.cpp
+++ b/lldb/tools/lldb-dap/lldb-dap.cpp
@@ -9,7 +9,9 @@
#include "DAP.h"
#include "EventHelper.h"
#include "Handler/RequestHandler.h"
+#include "MemoryMonitor.h"
#include "RunInTerminal.h"
+#include "lldb/API/SBDebugger.h"
#include "lldb/API/SBStream.h"
#include "lldb/Host/Config.h"
#include "lldb/Host/File.h"
@@ -504,9 +506,20 @@ int main(int argc, char *argv[]) {
return EXIT_FAILURE;
}
+ // Create a memory monitor. This can return nullptr if the host platform is
+ // not supported.
+ std::unique_ptr<MemoryMonitor> memory_monitor = MemoryMonitor::Create(
+ []() { lldb::SBDebugger::MemoryPressureDetected(); });
+
+ if (memory_monitor)
+ memory_monitor->Start();
+
// Terminate the debugger before the C++ destructor chain kicks in.
- auto terminate_debugger =
- llvm::make_scope_exit([] { lldb::SBDebugger::Terminate(); });
+ auto terminate_debugger = llvm::make_scope_exit([&] {
+ if (memory_monitor)
+ memory_monitor->Stop();
+ lldb::SBDebugger::Terminate();
+ });
std::vector<std::string> pre_init_commands;
for (const std::string &arg :
>From 59594877e40c60c29832f37a8ff5f1eb495f69f9 Mon Sep 17 00:00:00 2001
From: Jonas Devlieghere <jonas at devlieghere.com>
Date: Fri, 28 Feb 2025 17:07:55 -0600
Subject: [PATCH 2/5] Use the dispatch_get_global_queue and call
dispatch_release
---
lldb/tools/lldb-dap/MemoryMonitor.cpp | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/lldb/tools/lldb-dap/MemoryMonitor.cpp b/lldb/tools/lldb-dap/MemoryMonitor.cpp
index da3da42fe9b0f..a9118a89a82ac 100644
--- a/lldb/tools/lldb-dap/MemoryMonitor.cpp
+++ b/lldb/tools/lldb-dap/MemoryMonitor.cpp
@@ -33,7 +33,10 @@ class MemoryMonitorDarwin : public MemoryMonitor {
DISPATCH_SOURCE_TYPE_MEMORYPRESSURE,
0, // system-wide monitoring
DISPATCH_MEMORYPRESSURE_WARN | DISPATCH_MEMORYPRESSURE_CRITICAL,
- dispatch_get_main_queue());
+ dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0));
+
+ if (!m_memory_pressure_source)
+ return;
dispatch_source_set_event_handler(m_memory_pressure_source, ^{
dispatch_source_memorypressure_flags_t pressureLevel =
@@ -45,7 +48,12 @@ class MemoryMonitorDarwin : public MemoryMonitor {
});
}
- void Stop() override { dispatch_source_cancel(m_memory_pressure_source); }
+ void Stop() override {
+ if (m_memory_pressure_source) {
+ dispatch_source_cancel(m_memory_pressure_source);
+ dispatch_release(m_memory_pressure_source);
+ }
+ }
private:
dispatch_source_t m_memory_pressure_source;
>From 05632355c720cb80891d13acc174d5a86ea0d823 Mon Sep 17 00:00:00 2001
From: Jonas Devlieghere <jonas at devlieghere.com>
Date: Mon, 3 Mar 2025 17:02:04 -0600
Subject: [PATCH 3/5] Move MemoryMonitor into Host
---
.../lldb/Host}/MemoryMonitor.h | 8 +--
lldb/source/Host/CMakeLists.txt | 3 +-
.../Host/common}/MemoryMonitor.cpp | 50 ++----------------
lldb/source/Host/macosx/objcxx/CMakeLists.txt | 1 +
.../Host/macosx/objcxx/MemoryMonitorMacOSX.mm | 51 +++++++++++++++++++
lldb/tools/lldb-dap/CMakeLists.txt | 1 -
lldb/tools/lldb-dap/lldb-dap.cpp | 7 +--
7 files changed, 66 insertions(+), 55 deletions(-)
rename lldb/{tools/lldb-dap => include/lldb/Host}/MemoryMonitor.h (87%)
rename lldb/{tools/lldb-dap => source/Host/common}/MemoryMonitor.cpp (60%)
create mode 100644 lldb/source/Host/macosx/objcxx/MemoryMonitorMacOSX.mm
diff --git a/lldb/tools/lldb-dap/MemoryMonitor.h b/lldb/include/lldb/Host/MemoryMonitor.h
similarity index 87%
rename from lldb/tools/lldb-dap/MemoryMonitor.h
rename to lldb/include/lldb/Host/MemoryMonitor.h
index e07c3bde9e85c..504f5f9cba96b 100644
--- a/lldb/tools/lldb-dap/MemoryMonitor.h
+++ b/lldb/include/lldb/Host/MemoryMonitor.h
@@ -6,13 +6,13 @@
//
//===----------------------------------------------------------------------===//
-#ifndef LLDB_TOOLS_LLDB_DAP_WATCHPOINT_H
-#define LLDB_TOOLS_LLDB_DAP_WATCHPOINT_H
+#ifndef LLDB_HOST_MEMORYMONITOR_H
+#define LLDB_HOST_MEMORYMONITOR_H
#include <functional>
#include <memory>
-namespace lldb_dap {
+namespace lldb_private {
class MemoryMonitor {
public:
@@ -36,6 +36,6 @@ class MemoryMonitor {
Callback m_callback;
};
-} // namespace lldb_dap
+} // namespace lldb_private
#endif
diff --git a/lldb/source/Host/CMakeLists.txt b/lldb/source/Host/CMakeLists.txt
index cdfb6184f2219..f4be151756b3b 100644
--- a/lldb/source/Host/CMakeLists.txt
+++ b/lldb/source/Host/CMakeLists.txt
@@ -27,6 +27,7 @@ add_host_subdirectory(common
common/LockFileBase.cpp
common/LZMA.cpp
common/MainLoopBase.cpp
+ common/MemoryMonitor.cpp
common/MonitoringProcessLauncher.cpp
common/NativeProcessProtocol.cpp
common/NativeRegisterContext.cpp
@@ -136,7 +137,7 @@ else()
elseif (CMAKE_SYSTEM_NAME MATCHES "AIX")
add_host_subdirectory(aix
aix/HostInfoAIX.cpp
- )
+ )
endif()
endif()
diff --git a/lldb/tools/lldb-dap/MemoryMonitor.cpp b/lldb/source/Host/common/MemoryMonitor.cpp
similarity index 60%
rename from lldb/tools/lldb-dap/MemoryMonitor.cpp
rename to lldb/source/Host/common/MemoryMonitor.cpp
index a9118a89a82ac..7fa774b638415 100644
--- a/lldb/tools/lldb-dap/MemoryMonitor.cpp
+++ b/lldb/source/Host/common/MemoryMonitor.cpp
@@ -6,59 +6,20 @@
//
//===----------------------------------------------------------------------===//
-#include "MemoryMonitor.h"
+#include "lldb/Host/MemoryMonitor.h"
#include "llvm/ADT/ScopeExit.h"
#include <atomic>
#include <cstdio>
#include <cstring>
#include <thread>
-#if defined(__APPLE__)
-#include <dispatch/dispatch.h>
-#endif
-
#if defined(__linux__)
#include <fcntl.h>
#include <poll.h>
#include <unistd.h>
#endif
-using namespace lldb_dap;
-
-#if defined(__APPLE__)
-class MemoryMonitorDarwin : public MemoryMonitor {
- using MemoryMonitor::MemoryMonitor;
- void Start() override {
- m_memory_pressure_source = dispatch_source_create(
- DISPATCH_SOURCE_TYPE_MEMORYPRESSURE,
- 0, // system-wide monitoring
- DISPATCH_MEMORYPRESSURE_WARN | DISPATCH_MEMORYPRESSURE_CRITICAL,
- dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0));
-
- if (!m_memory_pressure_source)
- return;
-
- dispatch_source_set_event_handler(m_memory_pressure_source, ^{
- dispatch_source_memorypressure_flags_t pressureLevel =
- dispatch_source_get_data(m_memory_pressure_source);
- if (pressureLevel &
- (DISPATCH_MEMORYPRESSURE_WARN | DISPATCH_MEMORYPRESSURE_CRITICAL)) {
- m_callback();
- }
- });
- }
-
- void Stop() override {
- if (m_memory_pressure_source) {
- dispatch_source_cancel(m_memory_pressure_source);
- dispatch_release(m_memory_pressure_source);
- }
- }
-
-private:
- dispatch_source_t m_memory_pressure_source;
-};
-#endif
+using namespace lldb_private;
#if defined(__linux__)
static void MonitorThread(std::atomic<bool> &done,
@@ -109,14 +70,11 @@ class MemoryMonitorLinux : public MemoryMonitor {
};
#endif
+#if !defined(__APPLE__)
std::unique_ptr<MemoryMonitor> MemoryMonitor::Create(Callback callback) {
-#if defined(__APPLE__)
- return std::make_unique<MemoryMonitorDarwin>(callback);
-#endif
-
#if defined(__linux__)
return std::make_unique<MemoryMonitorLinux>(callback);
#endif
-
return nullptr;
}
+#endif
diff --git a/lldb/source/Host/macosx/objcxx/CMakeLists.txt b/lldb/source/Host/macosx/objcxx/CMakeLists.txt
index 1e693bed12ce1..cda8269ca9efd 100644
--- a/lldb/source/Host/macosx/objcxx/CMakeLists.txt
+++ b/lldb/source/Host/macosx/objcxx/CMakeLists.txt
@@ -6,6 +6,7 @@ add_lldb_library(lldbHostMacOSXObjCXX NO_PLUGIN_DEPENDENCIES
Host.mm
HostInfoMacOSX.mm
HostThreadMacOSX.mm
+ MemoryMonitorMacOSX.mm
LINK_LIBS
lldbUtility
diff --git a/lldb/source/Host/macosx/objcxx/MemoryMonitorMacOSX.mm b/lldb/source/Host/macosx/objcxx/MemoryMonitorMacOSX.mm
new file mode 100644
index 0000000000000..cb6c2457df1e3
--- /dev/null
+++ b/lldb/source/Host/macosx/objcxx/MemoryMonitorMacOSX.mm
@@ -0,0 +1,51 @@
+//===-- MemoryMonitorMacOSX.mm --------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Host/MemoryMonitor.h"
+#include <cassert>
+#include <dispatch/dispatch.h>
+
+using namespace lldb_private;
+
+class MemoryMonitorMacOSX : public MemoryMonitor {
+ using MemoryMonitor::MemoryMonitor;
+ void Start() override {
+ m_memory_pressure_source = dispatch_source_create(
+ DISPATCH_SOURCE_TYPE_MEMORYPRESSURE, 0,
+ DISPATCH_MEMORYPRESSURE_WARN | DISPATCH_MEMORYPRESSURE_CRITICAL,
+ dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0));
+
+ if (!m_memory_pressure_source)
+ return;
+
+ dispatch_source_set_event_handler(m_memory_pressure_source, ^{
+ dispatch_source_memorypressure_flags_t pressureLevel =
+ dispatch_source_get_data(m_memory_pressure_source);
+ if (pressureLevel &
+ (DISPATCH_MEMORYPRESSURE_WARN | DISPATCH_MEMORYPRESSURE_CRITICAL)) {
+ m_callback();
+ }
+ });
+ dispatch_activate(m_memory_pressure_source);
+ printf("Started\n");
+ }
+
+ void Stop() override {
+ if (m_memory_pressure_source) {
+ dispatch_source_cancel(m_memory_pressure_source);
+ dispatch_release(m_memory_pressure_source);
+ }
+ }
+
+private:
+ dispatch_source_t m_memory_pressure_source;
+};
+
+std::unique_ptr<MemoryMonitor> MemoryMonitor::Create(Callback callback) {
+ return std::make_unique<MemoryMonitorMacOSX>(callback);
+}
diff --git a/lldb/tools/lldb-dap/CMakeLists.txt b/lldb/tools/lldb-dap/CMakeLists.txt
index 8db377e31c3c6..8b3c520ec4360 100644
--- a/lldb/tools/lldb-dap/CMakeLists.txt
+++ b/lldb/tools/lldb-dap/CMakeLists.txt
@@ -36,7 +36,6 @@ add_lldb_tool(lldb-dap
RunInTerminal.cpp
SourceBreakpoint.cpp
Watchpoint.cpp
- MemoryMonitor.cpp
Handler/ResponseHandler.cpp
Handler/AttachRequestHandler.cpp
diff --git a/lldb/tools/lldb-dap/lldb-dap.cpp b/lldb/tools/lldb-dap/lldb-dap.cpp
index 41405df548da2..95d0efb1eef91 100644
--- a/lldb/tools/lldb-dap/lldb-dap.cpp
+++ b/lldb/tools/lldb-dap/lldb-dap.cpp
@@ -9,7 +9,6 @@
#include "DAP.h"
#include "EventHelper.h"
#include "Handler/RequestHandler.h"
-#include "MemoryMonitor.h"
#include "RunInTerminal.h"
#include "lldb/API/SBDebugger.h"
#include "lldb/API/SBStream.h"
@@ -17,6 +16,7 @@
#include "lldb/Host/File.h"
#include "lldb/Host/MainLoop.h"
#include "lldb/Host/MainLoopBase.h"
+#include "lldb/Host/MemoryMonitor.h"
#include "lldb/Host/Socket.h"
#include "lldb/Utility/Status.h"
#include "lldb/Utility/UriParser.h"
@@ -508,8 +508,9 @@ int main(int argc, char *argv[]) {
// Create a memory monitor. This can return nullptr if the host platform is
// not supported.
- std::unique_ptr<MemoryMonitor> memory_monitor = MemoryMonitor::Create(
- []() { lldb::SBDebugger::MemoryPressureDetected(); });
+ std::unique_ptr<lldb_private::MemoryMonitor> memory_monitor =
+ lldb_private::MemoryMonitor::Create(
+ []() { lldb::SBDebugger::MemoryPressureDetected(); });
if (memory_monitor)
memory_monitor->Start();
>From 9209e108976bc1c321dfd9ce895d707d99b20fe5 Mon Sep 17 00:00:00 2001
From: Jonas Devlieghere <jonas at devlieghere.com>
Date: Mon, 3 Mar 2025 19:17:14 -0600
Subject: [PATCH 4/5] Use NativeThread and attempt a Windows implementation
---
lldb/source/Host/common/MemoryMonitor.cpp | 106 ++++++++++++++--------
1 file changed, 68 insertions(+), 38 deletions(-)
diff --git a/lldb/source/Host/common/MemoryMonitor.cpp b/lldb/source/Host/common/MemoryMonitor.cpp
index 7fa774b638415..9fced2684a85c 100644
--- a/lldb/source/Host/common/MemoryMonitor.cpp
+++ b/lldb/source/Host/common/MemoryMonitor.cpp
@@ -7,11 +7,16 @@
//===----------------------------------------------------------------------===//
#include "lldb/Host/MemoryMonitor.h"
+#include "lldb/Host/HostThread.h"
+#include "lldb/Host/ThreadLauncher.h"
+#include "lldb/Utility/LLDBLog.h"
+#include "lldb/Utility/Log.h"
#include "llvm/ADT/ScopeExit.h"
+#include "llvm/Support/Error.h"
#include <atomic>
+#include <cstddef>
#include <cstdio>
#include <cstring>
-#include <thread>
#if defined(__linux__)
#include <fcntl.h>
@@ -19,62 +24,87 @@
#include <unistd.h>
#endif
+#if defined(_WIN32)
+#include <memoryapi.h>
+#include <synchapi.h>
+#endif
+
using namespace lldb_private;
+class MemoryMonitorPoll : public MemoryMonitor {
+public:
+ using MemoryMonitor::MemoryMonitor;
+
+ lldb::thread_result_t MonitorThread() {
#if defined(__linux__)
-static void MonitorThread(std::atomic<bool> &done,
- MemoryMonitor::Callback callback) {
- struct pollfd fds;
- fds.fd = open("/proc/pressure/memory", O_RDWR | O_NONBLOCK);
- if (fds.fd < 0)
- return;
- fds.events = POLLPRI;
-
- auto cleanup = llvm::make_scope_exit([&]() { close(fds.fd); });
-
- // Detect a 50ms stall in a 2 second time window.
- const char trig[] = "some 50000 2000000";
- if (write(fds.fd, trig, strlen(trig) + 1) < 0)
- return;
-
- while (!done) {
- int n = poll(&fds, 1, 1000);
- if (n > 0) {
- if (fds.revents & POLLERR)
- return;
- if (fds.revents & POLLPRI)
- callback();
+ struct pollfd fds;
+ fds.fd = open("/proc/pressure/memory", O_RDWR | O_NONBLOCK);
+ if (fds.fd < 0)
+ return {};
+ fds.events = POLLPRI;
+
+ auto cleanup = llvm::make_scope_exit([&]() { close(fds.fd); });
+
+ // Detect a 50ms stall in a 2 second time window.
+ const char trig[] = "some 50000 2000000";
+ if (write(fds.fd, trig, strlen(trig) + 1) < 0)
+ return {};
+
+ while (!m_done) {
+ int n = poll(&fds, 1, g_timeout);
+ if (n > 0) {
+ if (fds.revents & POLLERR)
+ return {};
+ if (fds.revents & POLLPRI)
+ m_callback();
+ }
}
- }
-}
+#endif
-class MemoryMonitorLinux : public MemoryMonitor {
-public:
- using MemoryMonitor::MemoryMonitor;
+#if defined(_WIN32)
+ HANDLE low_memory_notification =
+ CreateMemoryResourceNotification(LowMemoryResourceNotification);
+ if (!low_memory_notification)
+ return {};
+
+ while (!m_done) {
+ if (WaitForSingleObject(low_memory_notification, g_timeout) ==
+ WAIT_OBJECT_0) {
+ m_callback();
+ }
+ }
+#endif
+
+ return {};
+ }
void Start() override {
- m_memory_pressure_thread =
- std::thread(MonitorThread, std::ref(m_done), m_callback);
+ llvm::Expected<HostThread> memory_monitor_thread =
+ ThreadLauncher::LaunchThread("lldb.debugger.memory-monitor",
+ [this] { return MonitorThread(); });
+ if (memory_monitor_thread) {
+ m_memory_monitor_thread = *memory_monitor_thread;
+ } else {
+ LLDB_LOG_ERROR(GetLog(LLDBLog::Host), memory_monitor_thread.takeError(),
+ "failed to launch host thread: {0}");
+ }
}
void Stop() override {
- if (m_memory_pressure_thread.joinable()) {
+ if (m_memory_monitor_thread.IsJoinable()) {
m_done = true;
- m_memory_pressure_thread.join();
+ m_memory_monitor_thread.Join(nullptr);
}
}
private:
+ static constexpr uint32_t g_timeout = 1000;
std::atomic<bool> m_done = false;
- std::thread m_memory_pressure_thread;
+ HostThread m_memory_monitor_thread;
};
-#endif
#if !defined(__APPLE__)
std::unique_ptr<MemoryMonitor> MemoryMonitor::Create(Callback callback) {
-#if defined(__linux__)
- return std::make_unique<MemoryMonitorLinux>(callback);
-#endif
- return nullptr;
+ return std::make_unique<MemoryMonitorPoll>(callback);
}
#endif
>From f42780863a9dfbf66716aecf1c4c5ae0c2de7f81 Mon Sep 17 00:00:00 2001
From: Jonas Devlieghere <jonas at devlieghere.com>
Date: Tue, 4 Mar 2025 22:43:50 -0800
Subject: [PATCH 5/5] Include windows.h instead of memoryapi.h and synchapi.h
---
lldb/source/Host/common/MemoryMonitor.cpp | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/lldb/source/Host/common/MemoryMonitor.cpp b/lldb/source/Host/common/MemoryMonitor.cpp
index 9fced2684a85c..932fa9c43a22c 100644
--- a/lldb/source/Host/common/MemoryMonitor.cpp
+++ b/lldb/source/Host/common/MemoryMonitor.cpp
@@ -25,8 +25,7 @@
#endif
#if defined(_WIN32)
-#include <memoryapi.h>
-#include <synchapi.h>
+#include <windows.h>
#endif
using namespace lldb_private;
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