Merge "Use /proc/pid/smaps_rollup when available" into oc-mr1-dev am: ea7a45eb43

am: 18479e859f

Change-Id: I5f4905341fa81361c1e0feb8a65944d93f840907

3 files changed, 77 insertions, 18 deletions

diff --git a/core/jni/android_os_Debug.cpp b/core/jni/android_os_Debug.cpp
index 2702d1d29e4c..a140b57268d1 100644
--- a/core/jni/android_os_Debug.cpp
+++ b/core/jni/android_os_Debug.cpp
@@ -29,6 +29,7 @@
 #include <time.h>
 #include <unistd.h>
 
+#include <atomic>
 #include <iomanip>
 #include <string>
 
@@ -44,16 +45,11 @@
 #include "jni.h"
 #include <memtrack/memtrack.h>
 #include <memunreachable/memunreachable.h>
+#include "android_os_Debug.h"
 
 namespace android
 {
 
-static void safeFclose(FILE* fp) {
-  if (fp) fclose(fp);
-}
-
-using UniqueFile = std::unique_ptr<FILE, decltype(&safeFclose)>;
-
 static inline UniqueFile MakeUniqueFile(const char* path, const char* mode) {
     return UniqueFile(fopen(path, mode), safeFclose);
 }
@@ -155,6 +151,14 @@ struct stats_t {
     int swappedOutPss;
 };
 
+enum pss_rollup_support {
+  PSS_ROLLUP_UNTRIED,
+  PSS_ROLLUP_SUPPORTED,
+  PSS_ROLLUP_UNSUPPORTED
+};
+
+static std::atomic<pss_rollup_support> g_pss_rollup_support;
+
 #define BINDER_STATS "/proc/binder/stats"
 
 static jlong android_os_Debug_getNativeHeapSize(JNIEnv *env, jobject clazz)
@@ -548,6 +552,33 @@ static void android_os_Debug_getDirtyPages(JNIEnv *env, jobject clazz, jobject o
     android_os_Debug_getDirtyPagesPid(env, clazz, getpid(), object);
 }
 
+UniqueFile OpenSmapsOrRollup(int pid)
+{
+    enum pss_rollup_support rollup_support =
+            g_pss_rollup_support.load(std::memory_order_relaxed);
+    if (rollup_support != PSS_ROLLUP_UNSUPPORTED) {
+        std::string smaps_rollup_path =
+                base::StringPrintf("/proc/%d/smaps_rollup", pid);
+        UniqueFile fp_rollup = MakeUniqueFile(smaps_rollup_path.c_str(), "re");
+        if (fp_rollup == nullptr && errno != ENOENT) {
+            return fp_rollup;  // Actual error, not just old kernel.
+        }
+        if (fp_rollup != nullptr) {
+            if (rollup_support == PSS_ROLLUP_UNTRIED) {
+                ALOGI("using rollup pss collection");
+                g_pss_rollup_support.store(PSS_ROLLUP_SUPPORTED,
+                                           std::memory_order_relaxed);
+            }
+            return fp_rollup;
+        }
+        g_pss_rollup_support.store(PSS_ROLLUP_UNSUPPORTED,
+                                   std::memory_order_relaxed);
+    }
+
+    std::string smaps_path = base::StringPrintf("/proc/%d/smaps", pid);
+    return MakeUniqueFile(smaps_path.c_str(), "re");
+}
+
 static jlong android_os_Debug_getPssPid(JNIEnv *env, jobject clazz, jint pid,
         jlongArray outUssSwapPss, jlongArray outMemtrack)
 {
@@ -563,12 +594,11 @@ static jlong android_os_Debug_getPssPid(JNIEnv *env, jobject clazz, jint pid,
     }
 
     {
-        std::string smaps_path = base::StringPrintf("/proc/%d/smaps", pid);
-        UniqueFile fp = MakeUniqueFile(smaps_path.c_str(), "re");
+        UniqueFile fp = OpenSmapsOrRollup(pid);
 
         if (fp != nullptr) {
             while (true) {
-                if (fgets(line, 1024, fp.get()) == NULL) {
+                if (fgets(line, sizeof (line), fp.get()) == NULL) {
                     break;
                 }
 
diff --git a/core/jni/android_os_Debug.h b/core/jni/android_os_Debug.h
new file mode 100644
index 000000000000..81270ca994bb
--- /dev/null
+++ b/core/jni/android_os_Debug.h
@@ -0,0 +1,34 @@
+/*
+ * 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.
+ */
+
+#ifndef ANDROID_OS_DEBUG_H
+#define ANDROID_OS_DEBUG_H
+
+#include <memory>
+#include <stdio.h>
+
+namespace android {
+
+inline void safeFclose(FILE* fp) {
+  if (fp) fclose(fp);
+}
+
+using UniqueFile = std::unique_ptr<FILE, decltype(&safeFclose)>;
+UniqueFile OpenSmapsOrRollup(int pid);
+
+}  // namespace android
+
+#endif  // ANDROID_OS_HW_BLOB_H
diff --git a/core/jni/android_util_Process.cpp b/core/jni/android_util_Process.cpp
index 44f15cd637ed..33c8304f2547 100644
--- a/core/jni/android_util_Process.cpp
+++ b/core/jni/android_util_Process.cpp
@@ -31,6 +31,7 @@
 
 #include "android_util_Binder.h"
 #include <nativehelper/JNIHelp.h>
+#include "android_os_Debug.h"
 
 #include <dirent.h>
 #include <fcntl.h>
@@ -1092,27 +1093,21 @@ static jlong android_os_Process_getElapsedCpuTime(JNIEnv* env, jobject clazz)
 
 static jlong android_os_Process_getPss(JNIEnv* env, jobject clazz, jint pid)
 {
-    char filename[64];
-
-    snprintf(filename, sizeof(filename), "/proc/%" PRId32 "/smaps", pid);
-
-    FILE * file = fopen(filename, "r");
-    if (!file) {
+    UniqueFile file = OpenSmapsOrRollup(pid);
+    if (file == nullptr) {
         return (jlong) -1;
     }
 
     // Tally up all of the Pss from the various maps
     char line[256];
     jlong pss = 0;
-    while (fgets(line, sizeof(line), file)) {
+    while (fgets(line, sizeof(line), file.get())) {
         jlong v;
         if (sscanf(line, "Pss: %" SCNd64 " kB", &v) == 1) {
             pss += v;
         }
     }
 
-    fclose(file);
-
     // Return the Pss value in bytes, not kilobytes
     return pss * 1024;
 }