MediaMetrics: Move LimitProcessMemory to libmediautils

Eliminates the need for libmedia in media.metrics, cutting
RSS nearly in half.

Test: adb shell showmap '$(pgrep -f media.metrics)'
Test: adb shell showmap '$(pgrep -f media.extractor)'
Bug: 152256321
Change-Id: Id8aae66de84e712915888422b7372fd2b880570d
diff --git a/media/utils/LimitProcessMemory.cpp b/media/utils/LimitProcessMemory.cpp
new file mode 100644
index 0000000..623138f
--- /dev/null
+++ b/media/utils/LimitProcessMemory.cpp
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "MediaUtils"
+#define LOG_NDEBUG 0
+#include <utils/Log.h>
+
+#include <cutils/properties.h>
+#include <sys/resource.h>
+#include <unistd.h>
+
+#include <bionic/malloc.h>
+#include <mediautils/LimitProcessMemory.h>
+
+extern "C" void __scudo_set_rss_limit(size_t, int) __attribute__((weak));
+
+namespace android {
+
+void limitProcessMemory(const char *property, size_t numberOfBytes,
+                        size_t percentageOfTotalMem) {
+    long pageSize = sysconf(_SC_PAGESIZE);
+    long numPages = sysconf(_SC_PHYS_PAGES);
+    size_t maxMem = SIZE_MAX;
+
+    if (pageSize > 0 && numPages > 0) {
+        if (size_t(numPages) < SIZE_MAX / size_t(pageSize)) {
+            maxMem = size_t(numPages) * size_t(pageSize);
+        }
+        ALOGV("physMem: %zu", maxMem);
+        if (percentageOfTotalMem > 100) {
+            ALOGW("requested %zu%% of total memory, using 100%%", percentageOfTotalMem);
+            percentageOfTotalMem = 100;
+        }
+        maxMem = maxMem / 100 * percentageOfTotalMem;
+        if (numberOfBytes < maxMem) {
+            maxMem = numberOfBytes;
+        }
+        ALOGV("requested limit: %zu", maxMem);
+    } else {
+        ALOGW("couldn't determine total RAM");
+    }
+
+    int64_t propVal = property_get_int64(property, maxMem);
+    if (propVal > 0 && uint64_t(propVal) <= SIZE_MAX) {
+        maxMem = propVal;
+    }
+
+    // If Scudo is in use, enforce the hard RSS limit (in MB).
+    if (maxMem != SIZE_MAX && &__scudo_set_rss_limit != 0) {
+      __scudo_set_rss_limit(maxMem >> 20, 1);
+      ALOGV("Scudo hard RSS limit set to %zu MB", maxMem >> 20);
+      return;
+    }
+
+    if (!android_mallopt(M_SET_ALLOCATION_LIMIT_BYTES, &maxMem,
+                         sizeof(maxMem))) {
+      ALOGW("couldn't set allocation limit");
+    }
+}
+
+} // namespace android