commit f2588a8172a8481e4989924098eafa08a145b5c1
author Cody Northrop <cnorthrop@google.com> Mon Mar 27 23:03:49 2023 -0600
committer Cody Northrop <cnorthrop@google.com> Mon Apr 03 15:05:48 2023 -0600
tree 3eca8330e2d880e2fb1bf1d5959f56739350870a
parent be16373f15a245b4c14ad4f84b20ff8e76741893

EGL BlobCache: Trim immediately on multifile overflow

While adding a fuzzer for this feature, discovered that
cache trimming wasn't happening right when the overflow
happened, but on the next iteration.

This CL updates the code to make it trim right away, since
we've already determined it needs to happen.

Also add a test to ensure trimming happens right away.

Test: /data/nativetest64/EGL_test/EGL_test
Bug: b/266725576
Change-Id: Ica1e9ca688268e7e746750c27acdfced04e74b06

opengl/libs/EGL/MultifileBlobCache.cpp

diff --git a/opengl/libs/EGL/MultifileBlobCache.cpp b/opengl/libs/EGL/MultifileBlobCache.cpp
index f1b7a5c..1c0c045 100644
--- a/opengl/libs/EGL/MultifileBlobCache.cpp
+++ b/opengl/libs/EGL/MultifileBlobCache.cpp
@@ -267,7 +267,7 @@
     // If we're going to be over the cache limit, kick off a trim to clear space
     if (getTotalSize() + fileSize > mMaxTotalSize) {
         ALOGV("SET: Cache is full, calling trimCache to clear space");
-        trimCache(mMaxTotalSize);
+        trimCache();
     }
 
     ALOGV("SET: Add %u to cache", entryHash);
@@ -589,7 +589,7 @@
         }
     }
 
-    ALOGV("LRU: Cache is emptry");
+    ALOGV("LRU: Cache is empty");
     return false;
 }
 
@@ -598,24 +598,15 @@
 constexpr uint32_t kCacheLimitDivisor = 2;
 
 // Calculate the cache size and remove old entries until under the limit
-void MultifileBlobCache::trimCache(size_t cacheByteLimit) {
-    // Start with the value provided by egl_cache
-    size_t limit = cacheByteLimit;
-
+void MultifileBlobCache::trimCache() {
     // Wait for all deferred writes to complete
     ALOGV("TRIM: Waiting for work to complete.");
     waitForWorkComplete();
 
-    size_t size = getTotalSize();
-
-    // If size is larger than the threshold, remove files using LRU
-    if (size > limit) {
-        ALOGV("TRIM: Multifile cache size is larger than %zu, removing old entries",
-              cacheByteLimit);
-        if (!applyLRU(limit / kCacheLimitDivisor)) {
-            ALOGE("Error when clearing multifile shader cache");
-            return;
-        }
+    ALOGV("TRIM: Reducing multifile cache size to %zu", mMaxTotalSize / kCacheLimitDivisor);
+    if (!applyLRU(mMaxTotalSize / kCacheLimitDivisor)) {
+        ALOGE("Error when clearing multifile shader cache");
+        return;
     }
 }