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-rw-r--r--xpcom/base/nsMemoryImpl.cpp131
1 files changed, 131 insertions, 0 deletions
diff --git a/xpcom/base/nsMemoryImpl.cpp b/xpcom/base/nsMemoryImpl.cpp
new file mode 100644
index 0000000000..4996d27c7a
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+++ b/xpcom/base/nsMemoryImpl.cpp
@@ -0,0 +1,131 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsMemory.h"
+#include "nsThreadUtils.h"
+
+#include "nsIObserver.h"
+#include "nsIObserverService.h"
+#include "nsIRunnable.h"
+#include "nsISimpleEnumerator.h"
+
+#include "nsCOMPtr.h"
+#include "mozilla/Services.h"
+#include "mozilla/Atomics.h"
+
+#ifdef ANDROID
+# include <stdio.h>
+
+// Minimum memory threshold for a device to be considered
+// a low memory platform. This value has be in sync with
+// Java's equivalent threshold, defined in HardwareUtils.java
+# define LOW_MEMORY_THRESHOLD_KB (384 * 1024)
+#endif
+
+static mozilla::Atomic<bool> sIsFlushing;
+static PRIntervalTime sLastFlushTime = 0;
+
+// static
+bool nsMemory::IsLowMemoryPlatform() {
+#ifdef ANDROID
+ static int sLowMemory =
+ -1; // initialize to unknown, lazily evaluate to 0 or 1
+ if (sLowMemory == -1) {
+ sLowMemory = 0; // assume "not low memory" in case file operations fail
+
+ // check if MemTotal from /proc/meminfo is less than LOW_MEMORY_THRESHOLD_KB
+ FILE* fd = fopen("/proc/meminfo", "r");
+ if (!fd) {
+ return false;
+ }
+ uint64_t mem = 0;
+ int rv = fscanf(fd, "MemTotal: %" PRIu64 " kB", &mem);
+ if (fclose(fd)) {
+ return false;
+ }
+ if (rv != 1) {
+ return false;
+ }
+ sLowMemory = (mem < LOW_MEMORY_THRESHOLD_KB) ? 1 : 0;
+ }
+ return (sLowMemory == 1);
+#else
+ return false;
+#endif
+}
+
+static void RunFlushers(const char16_t* aReason) {
+ nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+ if (os) {
+ // Instead of:
+ // os->NotifyObservers(this, "memory-pressure", aReason);
+ // we are going to do this manually to see who/what is
+ // deallocating.
+
+ nsCOMPtr<nsISimpleEnumerator> e;
+ os->EnumerateObservers("memory-pressure", getter_AddRefs(e));
+
+ if (e) {
+ nsCOMPtr<nsIObserver> observer;
+ bool loop = true;
+
+ while (NS_SUCCEEDED(e->HasMoreElements(&loop)) && loop) {
+ nsCOMPtr<nsISupports> supports;
+ e->GetNext(getter_AddRefs(supports));
+
+ if (!supports) {
+ continue;
+ }
+
+ observer = do_QueryInterface(supports);
+ observer->Observe(observer, "memory-pressure", aReason);
+ }
+ }
+ }
+
+ sIsFlushing = false;
+}
+
+static nsresult FlushMemory(const char16_t* aReason, bool aImmediate) {
+ if (aImmediate) {
+ // They've asked us to run the flusher *immediately*. We've
+ // got to be on the UI main thread for us to be able to do
+ // that...are we?
+ if (!NS_IsMainThread()) {
+ NS_ERROR("can't synchronously flush memory: not on UI thread");
+ return NS_ERROR_FAILURE;
+ }
+ }
+
+ bool lastVal = sIsFlushing.exchange(true);
+ if (lastVal) {
+ return NS_OK;
+ }
+
+ PRIntervalTime now = PR_IntervalNow();
+
+ // Run the flushers immediately if we can; otherwise, proxy to the
+ // UI thread and run 'em asynchronously.
+ nsresult rv = NS_OK;
+ if (aImmediate) {
+ RunFlushers(aReason);
+ } else {
+ // Don't broadcast more than once every 1000ms to avoid being noisy
+ if (PR_IntervalToMicroseconds(now - sLastFlushTime) > 1000) {
+ nsCOMPtr<nsIRunnable> runnable(NS_NewRunnableFunction(
+ "FlushMemory",
+ [reason = aReason]() -> void { RunFlushers(reason); }));
+ NS_DispatchToMainThread(runnable.forget());
+ }
+ }
+
+ sLastFlushTime = now;
+ return rv;
+}
+
+nsresult nsMemory::HeapMinimize(bool aImmediate) {
+ return FlushMemory(u"heap-minimize", aImmediate);
+}