commit 3468f55d442bf980af9c3e675e0edf2efe2cff11
author Rick Yiu <rickyiu@google.com> Fri Dec 27 16:01:05 2019 +0800
committer Rick Yiu <rickyiu@google.com> Mon Feb 03 06:55:45 2020 +0000
tree 0fd7750ee2714ff1af4d639576fb9793e9d6189e
parent f32883ec66f0bdedafb87a2c215154e94a44d9da

Refine set_sched_policy behavior

If a thread priority is greater than or equal to
ANDROID_PRIORITY_BACKGROUND, and the new priority is less than
ANDROID_PRIORITY_BACKGROUND, set the sched policy to its parent process.

Bug: 139521784
Bug: 18249098
Test: functionality verified
Change-Id: Id0632cb53825cd7d342610713e100c651994d78f

palette_android.cc

diff --git a/palette_android.cc b/palette_android.cc
index e2d0036..cb13720 100644
--- a/palette_android.cc
+++ b/palette_android.cc
@@ -29,9 +29,10 @@
 #include <android-base/logging.h>
 #include <android-base/macros.h>
 #include <cutils/ashmem.h>
-#include <cutils/sched_policy.h>
 #include <cutils/trace.h>
 #include <log/event_tag_map.h>
+#include <processgroup/processgroup.h>
+#include <processgroup/sched_policy.h>
 #include <tombstoned/tombstoned.h>
 #include <utils/Thread.h>
 
@@ -66,18 +67,21 @@
         return PaletteStatus::kInvalidArgument;
     }
     int new_nice = kNiceValues[managed_priority - art::palette::kMinManagedThreadPriority];
+    int curr_nice = getpriority(PRIO_PROCESS, tid);
 
-    // TODO: b/18249098 The code below is broken. It uses getpriority() as a proxy for whether a
-    // thread is already in the SP_FOREGROUND cgroup. This is not necessarily true for background
-    // processes, where all threads are in the SP_BACKGROUND cgroup. This means that callers will
-    // have to call setPriority twice to do what they want :
-    //
-    //     Thread.setPriority(Thread.MIN_PRIORITY);  // no-op wrt to cgroups
-    //     Thread.setPriority(Thread.MAX_PRIORITY);  // will actually change cgroups.
+    if (curr_nice == new_nice) {
+        return PaletteStatus::kOkay;
+    }
+
     if (new_nice >= ANDROID_PRIORITY_BACKGROUND) {
-        set_sched_policy(tid, SP_BACKGROUND);
-    } else if (getpriority(PRIO_PROCESS, tid) >= ANDROID_PRIORITY_BACKGROUND) {
-        set_sched_policy(tid, SP_FOREGROUND);
+        SetTaskProfiles(tid, {"SCHED_SP_BACKGROUND"}, true);
+    } else if (curr_nice >= ANDROID_PRIORITY_BACKGROUND) {
+        SchedPolicy policy;
+        // Change to the sched policy group of the process.
+        if (get_sched_policy(getpid(), &policy) != 0) {
+            policy = SP_FOREGROUND;
+        }
+        SetTaskProfiles(tid, {get_sched_policy_profile_name(policy)}, true);
     }
 
     if (setpriority(PRIO_PROCESS, tid, new_nice) != 0) {