EGL: Close Multifile Blobcache files after mapping
When loading entries from disk, we don't need to keep the
files open after mapping their contents.
Per mmap documentation:
After the mmap() call has returned, the file descriptor, fd, can
be closed immediately without invalidating the mapping.
https://man7.org/linux/man-pages/man2/mmap.2.html
This will prevent consuming excessive file descriptors, which
are a limited resource.
Added new test that ensures file descriptors do not remain open.
Test: libEGL_test, EGL_test, restricted_trace_perf.py
Bug: b/286809755
Change-Id: I6317fdbce340a8e7cbf3020ad41386cf9915dd2d
diff --git a/opengl/libs/EGL/MultifileBlobCache.cpp b/opengl/libs/EGL/MultifileBlobCache.cpp
index 7ffdac7..ed3c616 100644
--- a/opengl/libs/EGL/MultifileBlobCache.cpp
+++ b/opengl/libs/EGL/MultifileBlobCache.cpp
@@ -48,9 +48,8 @@
void freeHotCacheEntry(android::MultifileHotCache& entry) {
if (entry.entryFd != -1) {
// If we have an fd, then this entry was added to hot cache via INIT or GET
- // We need to unmap and close the entry
+ // We need to unmap the entry
munmap(entry.entryBuffer, entry.entrySize);
- close(entry.entryFd);
} else {
// Otherwise, this was added to hot cache during SET, so it was never mapped
// and fd was only on the deferred thread.
@@ -143,6 +142,7 @@
if (result != sizeof(MultifileHeader)) {
ALOGE("Error reading MultifileHeader from cache entry (%s): %s",
fullPath.c_str(), std::strerror(errno));
+ close(fd);
return;
}
@@ -152,6 +152,7 @@
if (remove(fullPath.c_str()) != 0) {
ALOGE("Error removing %s: %s", fullPath.c_str(), std::strerror(errno));
}
+ close(fd);
continue;
}
@@ -161,6 +162,10 @@
// Memory map the file
uint8_t* mappedEntry = reinterpret_cast<uint8_t*>(
mmap(nullptr, fileSize, PROT_READ, MAP_PRIVATE, fd, 0));
+
+ // We can close the file now and the mmap will remain
+ close(fd);
+
if (mappedEntry == MAP_FAILED) {
ALOGE("Failed to mmap cacheEntry, error: %s", std::strerror(errno));
return;
@@ -206,13 +211,11 @@
if (!addToHotCache(entryHash, fd, mappedEntry, fileSize)) {
ALOGE("INIT Failed to add %u to hot cache", entryHash);
munmap(mappedEntry, fileSize);
- close(fd);
return;
}
} else {
// If we're not keeping it in hot cache, unmap it now
munmap(mappedEntry, fileSize);
- close(fd);
}
}
closedir(dir);
@@ -401,9 +404,12 @@
// Memory map the file
cacheEntry =
reinterpret_cast<uint8_t*>(mmap(nullptr, fileSize, PROT_READ, MAP_PRIVATE, fd, 0));
+
+ // We can close the file now and the mmap will remain
+ close(fd);
+
if (cacheEntry == MAP_FAILED) {
ALOGE("Failed to mmap cacheEntry, error: %s", std::strerror(errno));
- close(fd);
return 0;
}
diff --git a/opengl/libs/EGL/MultifileBlobCache_test.cpp b/opengl/libs/EGL/MultifileBlobCache_test.cpp
index dbee13b..1639be6 100644
--- a/opengl/libs/EGL/MultifileBlobCache_test.cpp
+++ b/opengl/libs/EGL/MultifileBlobCache_test.cpp
@@ -42,6 +42,8 @@
virtual void TearDown() { mMBC.reset(); }
+ int getFileDescriptorCount();
+
std::unique_ptr<TemporaryFile> mTempFile;
std::unique_ptr<MultifileBlobCache> mMBC;
};
@@ -216,4 +218,56 @@
ASSERT_EQ('y', buf[0]);
}
+int MultifileBlobCacheTest::getFileDescriptorCount() {
+ DIR* directory = opendir("/proc/self/fd");
+
+ int fileCount = 0;
+ struct dirent* entry;
+ while ((entry = readdir(directory)) != NULL) {
+ fileCount++;
+ // printf("File: %s\n", entry->d_name);
+ }
+
+ closedir(directory);
+ return fileCount;
+}
+
+TEST_F(MultifileBlobCacheTest, EnsureFileDescriptorsClosed) {
+ // Populate the cache with a bunch of entries
+ size_t kLargeNumberOfEntries = 1024;
+ for (int i = 0; i < kLargeNumberOfEntries; i++) {
+ // printf("Caching: %i", i);
+
+ // Use the index as the key and value
+ mMBC->set(&i, sizeof(i), &i, sizeof(i));
+
+ int result = 0;
+ ASSERT_EQ(sizeof(i), mMBC->get(&i, sizeof(i), &result, sizeof(result)));
+ ASSERT_EQ(i, result);
+ }
+
+ // Ensure we don't have a bunch of open fds
+ ASSERT_LT(getFileDescriptorCount(), kLargeNumberOfEntries / 2);
+
+ // Close the cache so everything writes out
+ mMBC->finish();
+ mMBC.reset();
+
+ // Now open it again and ensure we still don't have a bunch of open fds
+ mMBC.reset(
+ new MultifileBlobCache(kMaxKeySize, kMaxValueSize, kMaxTotalSize, &mTempFile->path[0]));
+
+ // Check after initialization
+ ASSERT_LT(getFileDescriptorCount(), kLargeNumberOfEntries / 2);
+
+ for (int i = 0; i < kLargeNumberOfEntries; i++) {
+ int result = 0;
+ ASSERT_EQ(sizeof(i), mMBC->get(&i, sizeof(i), &result, sizeof(result)));
+ ASSERT_EQ(i, result);
+ }
+
+ // And again after we've actually used it
+ ASSERT_LT(getFileDescriptorCount(), kLargeNumberOfEntries / 2);
+}
+
} // namespace android