commit 35221b53381c8823e237c04a71d9c2549114c52f
author Suren Baghdasaryan <surenb@google.com> Fri Nov 20 17:08:51 2020 -0800
committer Suren Baghdasaryan <surenb@google.com> Mon Nov 23 22:08:41 2020 +0000
tree 048a1f6b1f97e1c745835f4db54d102d949035c5
parent 03f4504ffdd7dac6a51efba7c4d181c50d23a9df

libprocessgroup: Support per-API level task profiles

When task profiles changes happen, devices released under older API
levels might have to use the same profiles as before. This might be
due to for missing kernel features or some other reasons. Add support
for per-API task profiles to accommodate this scenario. With this
mechanism when ro.product.first_api_level is non-empty, the system
looks for /system/etc/profiles/task_profiles_<api level>.json file
and uses it if it exists. If ro.product.first_api_level is not defined
or per-API task profiles file does not exist the system falls back to
the default /system/etc/profiles/task_profiles.json file.
As before, these task profiles can be competely overwritten using
/vendor/etc/task_profiles.json if needed.

Bug: 172066799
Test: boot with per-API task profiles
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: I1671b341b3a0fb5e99d0b0788315c61088326b09

libprocessgroup/task_profiles.cpp

diff --git a/libprocessgroup/task_profiles.cpp b/libprocessgroup/task_profiles.cpp
index 4e767db..db44228 100644
--- a/libprocessgroup/task_profiles.cpp
+++ b/libprocessgroup/task_profiles.cpp
@@ -23,6 +23,7 @@
 
 #include <android-base/file.h>
 #include <android-base/logging.h>
+#include <android-base/properties.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
 #include <android-base/threads.h>
@@ -38,13 +39,17 @@
 #endif
 
 using android::base::GetThreadId;
+using android::base::GetUintProperty;
 using android::base::StringPrintf;
 using android::base::StringReplace;
 using android::base::unique_fd;
 using android::base::WriteStringToFile;
 
-#define TASK_PROFILE_DB_FILE "/etc/task_profiles.json"
-#define TASK_PROFILE_DB_VENDOR_FILE "/vendor/etc/task_profiles.json"
+static constexpr const char* TASK_PROFILE_DB_FILE = "/etc/task_profiles.json";
+static constexpr const char* TASK_PROFILE_DB_VENDOR_FILE = "/vendor/etc/task_profiles.json";
+
+static constexpr const char* TEMPLATE_TASK_PROFILE_API_FILE =
+        "/etc/task_profiles/task_profiles_%u.json";
 
 void ProfileAttribute::Reset(const CgroupController& controller, const std::string& file_name) {
     controller_ = controller;
@@ -386,9 +391,21 @@
 }
 
 TaskProfiles::TaskProfiles() {
+    unsigned int api_level = GetUintProperty<unsigned int>("ro.product.first_api_level", 0);
+    std::string sys_profiles_path = TASK_PROFILE_DB_FILE;
+
+    // load API-level specific system task profiles if available
+    if (api_level > 0) {
+        std::string api_profiles_path =
+                android::base::StringPrintf(TEMPLATE_TASK_PROFILE_API_FILE, api_level);
+        if (!access(api_profiles_path.c_str(), F_OK) || errno != ENOENT) {
+            sys_profiles_path = api_profiles_path;
+        }
+    }
+
     // load system task profiles
-    if (!Load(CgroupMap::GetInstance(), TASK_PROFILE_DB_FILE)) {
-        LOG(ERROR) << "Loading " << TASK_PROFILE_DB_FILE << " for [" << getpid() << "] failed";
+    if (!Load(CgroupMap::GetInstance(), sys_profiles_path)) {
+        LOG(ERROR) << "Loading " << sys_profiles_path << " for [" << getpid() << "] failed";
     }
 
     // load vendor task profiles if the file exists