Docs: Changes to source.android.com

  - 210393380 Devsite localized content from translation request 956020. by Android Partner Docs <noreply@android.com>
  - 210170698 Adding new image + minor text change (to force update) by Heidi von Markham <hvm@google.com>
  - 210148653 Clarify per-process and per-transaction HIDL limits. by Android Partner Docs <noreply@android.com>
  - 210104185 Devsite localized content from translation request 967290. by Android Partner Docs <noreply@android.com>
  - 210104178 Devsite localized content from translation request 965872. by Android Partner Docs <noreply@android.com>
  - 209982772 Publish August localized bulletins by Danielle Roberts <daroberts@google.com>
  - 209955311 Devsite localized content from translation request 965875. by Android Partner Docs <noreply@android.com>
  - 209955290 Devsite localized content from translation request 964300. by Android Partner Docs <noreply@android.com>
  - 209955273 Devsite localized content from translation request 965637. by Android Partner Docs <noreply@android.com>
  - 209953339 Add LMKD in Userspace post P release by Clay Murphy <claym@google.com>
  - 209942277 Update Secure Element by Kenneth Lau <kennethlau@google.com>
  - 209941970 Simplify first sentence of restore entry by Clay Murphy <claym@google.com>
  - 209832932 Devsite localized content from translation request 963844. by Android Partner Docs <noreply@android.com>
  - 209697578 Add better app widgets to P release notes by Clay Murphy <claym@google.com>
  - 209683102 Add Restore to lower APIs in P release notes by Clay Murphy <claym@google.com>
  - 209645764 Update Carrier Wi-Fi by Kenneth Lau <kennethlau@google.com>

PiperOrigin-RevId: 210393380
Change-Id: Ic22fce750987853d802698809207ac8172e2ba74

4 files changed, 252 insertions, 17 deletions

diff --git a/en/devices/_toc-performance.yaml b/en/devices/_toc-performance.yaml
index 83f31408..174534dd 100644
--- a/en/devices/_toc-performance.yaml
+++ b/en/devices/_toc-performance.yaml
@@ -11,6 +11,8 @@ toc:
   path: /devices/tech/perf/apk-caching
 - title: Boot Times
   path: /devices/tech/perf/boot-times
+- title: LMKD in Userspace
+  path: /devices/tech/perf/lmkd
 - title: Low RAM
   path: /devices/tech/perf/low-ram
 - title: Profile Guided Optimization (PGO)
diff --git a/en/devices/architecture/hidl/services.html b/en/devices/architecture/hidl/services.html
index c7ddd8f6..f441c8e2 100644
--- a/en/devices/architecture/hidl/services.html
+++ b/en/devices/architecture/hidl/services.html
@@ -168,14 +168,15 @@ or <code>oneway</code>. For an example, see "Asynchronous callbacks" in
 <code>inout</code> parameters.</p>
 
 <h3 id=limits>Per-transaction limits</h3>
-<p>Per-transaction limits may be imposed on the amount of data sent in HIDL
-methods and callbacks. The limits are yet to be determined but may be as small
-as 4K. Calls exceeding these limits return failure immediately. Another
-limitation is the resources available to the HIDL infrastructure to handle
-multiple simultaneous transactions. Multiple transactions can be in-flight
-simultaneously due to multiple threads or processes sending calls to a process
-or multiple <code>oneway</code> calls that are not handled quickly by the
-receiving process.</p>
+<p>Per-transaction limits are not imposed on the amount of data sent in HIDL
+methods and callbacks. However, calls exceeding 4KB per transaction are
+considered excessive. If this is seen, re-architecting the given HIDL interface
+is recommended. Another limitation is the resources available to the HIDL
+infrastructure to handle multiple simultaneous transactions. Multiple
+transactions can be in-flight simultaneously due to multiple threads or
+processes sending calls to a process or multiple <code>oneway</code> calls that
+are not handled quickly by the receiving process. The maximum total space
+available for all concurrent transactions is 1MB by default.</p>
 
 <p>In a well-designed interface, exceeding these resource limitations should not
 happen; if it does, the call which exceeded them may either block until
diff --git a/en/devices/tech/connect/carrier-wifi.md b/en/devices/tech/connect/carrier-wifi.md
index be25f4b9..9e96c391 100644
--- a/en/devices/tech/connect/carrier-wifi.md
+++ b/en/devices/tech/connect/carrier-wifi.md
@@ -34,15 +34,50 @@ Wi-Fi.
 
 ### Manufacturers
 
-In the carrier config manager, configure the following parameters, located in
-[`CarrierConfigManager.java`](https://android.googlesource.com/platform/frameworks/base/+/master/telephony/java/android/telephony/CarrierConfigManager.java){: .external},
-for each carrier:
-
-+   `KEY_CARRIER_WIFI_STRING_ARRAY`: Base64-encoded Wi-Fi SSID.
-+   `IMSI_KEY_AVAILABILITY_INT`: Identifies whether the key used for IMSI
-    encryption is available for WLAN or EPDG, or both.
-+   `IMSI_KEY_DOWNLOAD_URL_STRING`: URL from which the proto containing the
-    public key of the carrier used for IMSI encryption is downloaded.
+In the carrier config manager,  configure the following parameters for each
+carrier:
+
++  [`KEY_CARRIER_WIFI_STRING_ARRAY`](https://android.googlesource.com/platform/frameworks/base/+/master/telephony/java/android/telephony/CarrierConfigManager.java#1606){: .external}:
+    A string array where each string entry is a Base64-encoded Wi-Fi SSID and
+    an EAP type separated by a comma, where the EAP type is an integer (refer to
+    [https://www.iana.org/assignments/eap-numbers/eap-numbers.xhtml](https://www.iana.org/assignments/eap-numbers/eap-numbers.xhtml){: .external}).
+    For example, the following configuration is for *SOME_SSID_NAME* using
+    **EAP-AKA** and *Some_Other_SSID* using **EAP-SIM**:
+
+    ```
+    config {
+      key: "carrier_wifi_string_array"
+      text_array {
+        item: "U09NRV9TU0lEX05BTUUK,23"
+        item: "U29tZV9PdGhlcl9TU0lECg==,18"
+      }
+    }
+    ```
+
++  [`IMSI_KEY_AVAILABILITY_INT`](https://android.googlesource.com/platform/frameworks/base/+/master/telephony/java/android/telephony/CarrierConfigManager.java#1837){: .external}:
+    Identifies whether the key used for IMSI encryption is available for WLAN
+    (bit 1 is set), EPDG (bit 0 is set), or both (both bit 0 and bit 1 are
+    set). For example, the following configuration indicates that IMSI
+    encryption is available for WLAN but not for EPDG:
+
+    ```
+    config {
+      key: "imsi_key_availability_int"
+      int_value: 2
+    }
+    ```
+
++  [`IMSI_KEY_DOWNLOAD_URL_STRING`](https://android.googlesource.com/platform/frameworks/base/+/master/telephony/java/android/telephony/CarrierConfigManager.java#1830){: .external}:
+    URL from which the proto containing the public key of the carrier used for
+    IMSI encryption is downloaded. For example, the following configuration
+    provides a specific URL:
+
+    ```
+    config {
+      key: "imsi_key_download_url_string"
+      text_value: "https://www.some_company_name.com:5555/some_directory_name/"
+    }
+    ```
 
 ### Carriers
 
diff --git a/en/devices/tech/perf/lmkd.md b/en/devices/tech/perf/lmkd.md
new file mode 100644
index 00000000..72ff452b
--- /dev/null
+++ b/en/devices/tech/perf/lmkd.md
@@ -0,0 +1,197 @@
+Project: /_project.yaml
+Book: /_book.yaml
+
+{% include "_versions.html" %}
+
+<!--
+  Copyright 2018 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.
+-->
+
+# LMKD in Userspace
+
+This document describes the userspace lowmemorykiller daemon (`lmkd`) features
+added in Android {{ androidPVersionNumber }} and how to configure them.
+
+Historically, Android used in-kernel lowmemorykiller driver to handle memory
+pressure situations by killing non-essential processes. This mechanism is rigid
+and depends on hard-coded values. In addition, starting with kernel 4.12, the
+lowmemorykiller driver is excluded from the upstream kernel.
+
+The userspace `lmkd` process implements the same functionality but with already
+existing kernel mechanisms to detect and estimate memory pressure. It uses
+vmpressure events generated by the kernel to get notifications about memory
+pressure levels.  It also can use memory cgroup features to limit memory resources
+allocated to each process based on its importance.
+
+
+# How to switch to userspace lmkd
+
+Starting in Android {{ androidPVersionNumber }}, userspace `lmkd` activates if an
+in-kernel lowmemorykiller driver is not detected. Note that userspace `lmkd`
+requires kernel support for memory cgroups. Therefore, to switch to userspace
+`lmkd` the kernel should be compiled with the following configuration  settings:
+
+```
+CONFIG_ANDROID_LOW_MEMORY_KILLER=n
+CONFIG_MEMCG=y
+CONFIG_MEMCG_SWAP=y
+```
+
+# lmkd kill strategies
+
+`lmkd` supports new kill strategies based on vmpressure events, their severity,
+and other hints like swap utilization, as well as legacy mode in which `lmkd`
+makes kill decisions just as the kernel lowmemorykiller driver did.
+
+New kill strategies differ for low-memory vs high-performance devices. In cases
+of low-memory devices, the system should tolerate higher memory pressure as a
+normal mode of operation; on high-performance devices, memory pressure should be
+viewed as an abnormal situation that should be fixed before it affects overall
+performance. The `ro.config.low_ram` property allows for choosing one mode over
+the other. See [Low RAM Configuration](/devices/tech/perf/low-ram) for
+instructions on setting this property.
+
+In legacy mode, `lmkd` kill decisions are made based on free memory and file cache
+thresholds. This mode is enabled by setting the `ro.lmk.use_minfree_levels`
+property to `true`.
+
+
+# Configuring lmkd for specific device
+
+Configure `lmkd` with the following properties:
+
+<table>
+  <tr>
+   <th>Property</th>
+   <th>Use</th>
+   <th>Default Value</th>
+  </tr>
+  <tr>
+   <td><code>ro.config.low_ram</code>
+   </td>
+   <td>Choose between low-memory vs. high-performance device.
+   </td>
+   <td><code>false</code>
+   </td>
+  </tr>
+  <tr>
+   <td><code>ro.lmk.use_minfree_levels</code>
+   </td>
+   <td>Use free memory and file cache thresholds for making decisions when to
+   kill. This mode works the same way kernel lowmemorykiller driver used to
+   work.
+   </td>
+   <td><code>false</code>
+   </td>
+  </tr>
+  <tr>
+   <td><code>ro.lmk.low</code>
+   </td>
+   <td>The minimum oom_adj score for processes eligible to be killed at low
+   vmpressure level.
+   </td>
+   <td><code>1001</code><br>
+(disabled)
+   </td>
+  </tr>
+  <tr>
+   <td><code>ro.lmk.medium</code>
+   </td>
+   <td>The minimum oom_adj score for processes eligible to be killed at medium
+   vmpressure level.
+   </td>
+   <td><code>800</code><br>
+(cached or non-essential services)
+   </td>
+  </tr>
+  <tr>
+   <td><code>ro.lmk.critical</code>
+   </td>
+   <td>The minimum oom_adj score for processes eligible to be killed at critical
+   vmpressure level.
+   </td>
+   <td><code>0</code><br>
+(any process)
+   </td>
+  </tr>
+  <tr>
+   <td><code>ro.lmk.critical_upgrade</code>
+   </td>
+   <td>Enables upgrade to critical level.
+   </td>
+   <td><code>false</code>
+   </td>
+  </tr>
+  <tr>
+   <td><code>ro.lmk.upgrade_pressure</code>
+   </td>
+   <td>The maximum mem_pressure at which level will be upgraded because system
+   is swapping too much.
+   </td>
+   <td><code>100</code><br>
+(disabled)
+   </td>
+  </tr>
+  <tr>
+   <td><code>ro.lmk.downgrade_pressure</code>
+   </td>
+   <td>The minimum mem_pressure* at which vmpressure event will be ignored
+   because enough free memory is still available.
+   </td>
+   <td><code>100</code><br>
+(disabled)
+   </td>
+  </tr>
+  <tr>
+   <td><code>ro.lmk.kill_heaviest_task</code>
+   </td>
+   <td>Kill heaviest eligible task (best decision) vs. any eligible task (fast
+   decision).</td>
+   <td><code>true</code>
+   </td>
+  </tr>
+  <tr>
+   <td><code>ro.lmk.kill_timeout_ms</code>
+   </td>
+   <td>Duration in ms after a kill when no additional kill will be done.
+   </td>
+   <td><code>0</code><br>
+(disabled)
+   </td>
+  </tr>
+  <tr>
+   <td><code>ro.lmk.debug</code>
+   </td>
+   <td>Enable <code>lmkd</code> debug logs.
+   </td>
+   <td><code>false</code>
+   </td>
+  </tr>
+</table>
+
+*Note: *mem_pressure = RAM usage / RAM_and_swap usage in %
+
+Here is a device configuration example:
+
+```
+PRODUCT_PROPERTY_OVERRIDES += \
+    ro.lmk.low=1001 \
+    ro.lmk.medium=800 \
+    ro.lmk.critical=0 \
+    ro.lmk.critical_upgrade=false \
+    ro.lmk.upgrade_pressure=100 \
+    ro.lmk.downgrade_pressure=100 \
+    ro.lmk.kill_heaviest_task=true
+```