commit d620a390daf48f122942ce5d08a40ff409bd6aa0
author David Stevens <stevensd@google.com> Tue Oct 20 15:00:41 2020 +0900
committer Sungtak Lee <taklee@google.com> Tue Dec 08 22:36:53 2020 +0000
tree 3126f42125f718f4f6286629a1aa5a96f1c94a3d
parent 9b95dd2f7e88bd1ddaf5b765ffe7845cabe6edbc

BufferPool: limit number of idle buffers in caches

Some systems have limits on the total number of graphics buffers that
can be allocated, not just the total size. When dealing with
particularly small buffers, the caches could end up retaining 1000s of
buffers.  This change adds an additional eviction trigger based on the
number of idle cached buffers.

Bug: 170702290
Test: android.video.cts.VideoEncoderDecoderTest on ARCVM
Change-Id: If3f4433ba1794ccb624b864a56619c8613a315f2
(cherry picked from commit 0f50e523ef1404f9afbaa7b919e2801e5d94012a)
Merged-In: If3f4433ba1794ccb624b864a56619c8613a315f2

media/bufferpool/2.0/AccessorImpl.cpp

diff --git a/media/bufferpool/2.0/AccessorImpl.cpp b/media/bufferpool/2.0/AccessorImpl.cpp
index 6111fea..1d2562e 100644
--- a/media/bufferpool/2.0/AccessorImpl.cpp
+++ b/media/bufferpool/2.0/AccessorImpl.cpp
@@ -39,6 +39,8 @@
 
     static constexpr size_t kMinAllocBytesForEviction = 1024*1024*15;
     static constexpr size_t kMinBufferCountForEviction = 25;
+    static constexpr size_t kMaxUnusedBufferCount = 64;
+    static constexpr size_t kUnusedBufferCountTarget = kMaxUnusedBufferCount - 16;
 
     static constexpr nsecs_t kEvictGranularityNs = 1000000000; // 1 sec
     static constexpr nsecs_t kEvictDurationNs = 5000000000; // 5 secs
@@ -724,9 +726,11 @@
 }
 
 void Accessor::Impl::BufferPool::cleanUp(bool clearCache) {
-    if (clearCache || mTimestampUs > mLastCleanUpUs + kCleanUpDurationUs) {
+    if (clearCache || mTimestampUs > mLastCleanUpUs + kCleanUpDurationUs ||
+            mStats.buffersNotInUse() > kMaxUnusedBufferCount) {
         mLastCleanUpUs = mTimestampUs;
-        if (mTimestampUs > mLastLogUs + kLogDurationUs) {
+        if (mTimestampUs > mLastLogUs + kLogDurationUs ||
+                mStats.buffersNotInUse() > kMaxUnusedBufferCount) {
             mLastLogUs = mTimestampUs;
             ALOGD("bufferpool2 %p : %zu(%zu size) total buffers - "
                   "%zu(%zu size) used buffers - %zu/%zu (recycle/alloc) - "
@@ -737,8 +741,9 @@
                   mStats.mTotalFetches, mStats.mTotalTransfers);
         }
         for (auto freeIt = mFreeBuffers.begin(); freeIt != mFreeBuffers.end();) {
-            if (!clearCache && (mStats.mSizeCached < kMinAllocBytesForEviction
-                    || mBuffers.size() < kMinBufferCountForEviction)) {
+            if (!clearCache && mStats.buffersNotInUse() <= kUnusedBufferCountTarget &&
+                    (mStats.mSizeCached < kMinAllocBytesForEviction ||
+                     mBuffers.size() < kMinBufferCountForEviction)) {
                 break;
             }
             auto it = mBuffers.find(*freeIt);