Merge "set the extra_free_kbytes kernel vm tunable"

3 files changed, 39 insertions, 0 deletions

diff --git a/core/res/res/values/config.xml b/core/res/res/values/config.xml
index 7647917352b6..8e86950f68ad 100644
--- a/core/res/res/values/config.xml
+++ b/core/res/res/values/config.xml
@@ -152,6 +152,24 @@
          bucket, and scaled proportionally to the smaller buckets. 0 keeps the default. -->
     <integer name="config_lowMemoryKillerMinFreeKbytesAdjust">0</integer>
 
+    <!-- Device configuration setting the /proc/sys/vm/extra_free_kbytes tunable in the kernel
+         (if it exists).  A high value will increase the amount of memory that the kernel
+         tries to keep free, reducing allocation time and causing the lowmemorykiller to kill
+         earlier.  A low value allows more memory to be used by processes but may cause more
+         allocations to block waiting on disk I/O or lowmemorykiller.  Overrides the default
+         value chosen by ActivityManager based on screen size.  0 prevents keeping any extra
+         memory over what the kernel keeps by default.  -1 keeps the default. -->
+    <integer name="config_extraFreeKbytesAbsolute">-1</integer>
+
+    <!-- Device configuration adjusting the /proc/sys/vm/extra_free_kbytes tunable in the kernel
+         (if it exists).  0 uses the default value chosen by ActivityManager.  A positive value
+         will increase the amount of memory that the kernel tries to keep free, reducing
+         allocation time and causing the lowmemorykiller to kill earlier.  A negative value
+         allows more memory to be used by processes but may cause more allocations to block
+         waiting on disk I/O or lowmemorykiller.  Directly added to the default value chosen by
+         ActivityManager based on screen size. -->
+    <integer name="config_extraFreeKbytesAdjust">0</integer>
+
     <!-- The duration (in milliseconds) that the radio will scan for a signal
          when there's no network connection. If the scan doesn't timeout, use zero -->
     <integer name="config_radioScanningTimeout">0</integer>
diff --git a/core/res/res/values/symbols.xml b/core/res/res/values/symbols.xml
index f1eae82420a0..008c3340578a 100755
--- a/core/res/res/values/symbols.xml
+++ b/core/res/res/values/symbols.xml
@@ -283,6 +283,8 @@
   <java-symbol type="bool" name="config_useFixedVolume" />
 
   <java-symbol type="integer" name="config_cursorWindowSize" />
+  <java-symbol type="integer" name="config_extraFreeKbytesAdjust" />
+  <java-symbol type="integer" name="config_extraFreeKbytesAbsolute" />
   <java-symbol type="integer" name="config_longPressOnPowerBehavior" />
   <java-symbol type="integer" name="config_lowMemoryKillerMinFreeKbytesAdjust" />
   <java-symbol type="integer" name="config_lowMemoryKillerMinFreeKbytesAbsolute" />
diff --git a/services/java/com/android/server/am/ProcessList.java b/services/java/com/android/server/am/ProcessList.java
index 0642a6ca10be..ae5c65278de0 100644
--- a/services/java/com/android/server/am/ProcessList.java
+++ b/services/java/com/android/server/am/ProcessList.java
@@ -24,6 +24,7 @@ import com.android.server.wm.WindowManagerService;
 
 import android.content.res.Resources;
 import android.graphics.Point;
+import android.os.SystemProperties;
 import android.util.Slog;
 import android.view.Display;
 
@@ -237,10 +238,28 @@ final class ProcessList {
             memString.append((mOomMinFree[i]*1024)/PAGE_SIZE);
         }
 
+        // Ask the kernel to try to keep enough memory free to allocate 3 full
+        // screen 32bpp buffers without entering direct reclaim.
+        int reserve = displayWidth * displayHeight * 4 * 3 / 1024;
+        int reserve_adj = Resources.getSystem().getInteger(com.android.internal.R.integer.config_extraFreeKbytesAdjust);
+        int reserve_abs = Resources.getSystem().getInteger(com.android.internal.R.integer.config_extraFreeKbytesAbsolute);
+
+        if (reserve_abs >= 0) {
+            reserve = reserve_abs;
+        }
+
+        if (reserve_adj != 0) {
+            reserve += reserve_adj;
+            if (reserve < 0) {
+                reserve = 0;
+            }
+        }
+
         //Slog.i("XXXXXXX", "******************************* MINFREE: " + memString);
         if (write) {
             writeFile("/sys/module/lowmemorykiller/parameters/adj", adjString.toString());
             writeFile("/sys/module/lowmemorykiller/parameters/minfree", memString.toString());
+            SystemProperties.set("sys.sysctl.extra_free_kbytes", Integer.toString(reserve));
         }
         // GB: 2048,3072,4096,6144,7168,8192
         // HC: 8192,10240,12288,14336,16384,20480