Merge "Prevent double-counting of kernel stack size in dumpsys reports"

core/java/android/os/Debug.java

@@ -2526,4 +2526,12 @@ public final class Debug
      * @hide
      */
     public static native long getIonMappedSizeKb();
+
+    /**
+     * Return whether virtually-mapped kernel stacks are enabled (CONFIG_VMAP_STACK).
+     * Note: caller needs config_gz read sepolicy permission
+     *
+     * @hide
+     */
+    public static native boolean isVmapStack();
 }

core/java/com/android/internal/util/MemInfoReader.java

@@ -107,9 +107,12 @@ public final class MemInfoReader {
      * Amount of RAM that is in use by the kernel for actual allocations.
      */
     public long getKernelUsedSizeKb() {
-        return mInfos[Debug.MEMINFO_SHMEM] + mInfos[Debug.MEMINFO_SLAB_UNRECLAIMABLE]
-                + mInfos[Debug.MEMINFO_VM_ALLOC_USED] + mInfos[Debug.MEMINFO_PAGE_TABLES]
-                + mInfos[Debug.MEMINFO_KERNEL_STACK];
+        long size = mInfos[Debug.MEMINFO_SHMEM] + mInfos[Debug.MEMINFO_SLAB_UNRECLAIMABLE]
+                + mInfos[Debug.MEMINFO_VM_ALLOC_USED] + mInfos[Debug.MEMINFO_PAGE_TABLES];
+        if (!Debug.isVmapStack()) {
+            size += mInfos[Debug.MEMINFO_KERNEL_STACK];
+        }
+        return size;
     }
 
     public long getSwapTotalSizeKb() {

core/jni/android_os_Debug.cpp

@@ -50,6 +50,7 @@
 #include <memunreachable/memunreachable.h>
 #include <android-base/strings.h>
 #include "android_os_Debug.h"
+#include <vintf/VintfObject.h>
 
 namespace android
 {
@@ -833,6 +834,23 @@ static jlong android_os_Debug_getIonMappedSizeKb(JNIEnv* env, jobject clazz) {
     return ionPss;
 }
 
+static jboolean android_os_Debug_isVmapStack(JNIEnv *env, jobject clazz)
+{
+    static enum {
+        CONFIG_UNKNOWN,
+        CONFIG_SET,
+        CONFIG_UNSET,
+    } cfg_state = CONFIG_UNKNOWN;
+
+    if (cfg_state == CONFIG_UNKNOWN) {
+        const std::map<std::string, std::string> configs =
+            vintf::VintfObject::GetInstance()->getRuntimeInfo()->kernelConfigs();
+        std::map<std::string, std::string>::const_iterator it = configs.find("CONFIG_VMAP_STACK");
+        cfg_state = (it != configs.end() && it->second == "y") ? CONFIG_SET : CONFIG_UNSET;
+    }
+    return cfg_state == CONFIG_SET;
+}
+
 /*
  * JNI registration.
  */
@@ -882,6 +900,8 @@ static const JNINativeMethod gMethods[] = {
             (void*)android_os_Debug_getIonPoolsSizeKb },
     { "getIonMappedSizeKb", "()J",
             (void*)android_os_Debug_getIonMappedSizeKb },
+    { "isVmapStack", "()Z",
+            (void*)android_os_Debug_isVmapStack },
 };
 
 int register_android_os_Debug(JNIEnv *env)