ART: Discard generated image in a low-memory environment
In case the available memory after image generation is low,
discard the image and continue in interpreted mode to mitigate
low-mem issues.
Bug: 17975190
(cherry picked from commit e059b778a6a471455659eb8c3616858eb189fda8)
Change-Id: I9bbb5e52ffbf3570f85510efb76bcd7654e6951c
diff --git a/runtime/gc/space/image_space.cc b/runtime/gc/space/image_space.cc
index 6e1639c..f03ea31 100644
--- a/runtime/gc/space/image_space.cc
+++ b/runtime/gc/space/image_space.cc
@@ -17,6 +17,7 @@
#include "image_space.h"
#include <dirent.h>
+#include <sys/statvfs.h>
#include <sys/types.h>
#include <random>
@@ -376,6 +377,41 @@
return false;
}
+static constexpr uint64_t kLowSpaceValue = 50 * MB;
+static constexpr uint64_t kTmpFsSentinelValue = 384 * MB;
+
+// Read the free space of the cache partition and make a decision whether to keep the generated
+// image. This is to try to mitigate situations where the system might run out of space later.
+static bool CheckSpace(const std::string& cache_filename, std::string* error_msg) {
+ // Using statvfs vs statvfs64 because of b/18207376, and it is enough for all practical purposes.
+ struct statvfs buf;
+
+ int res = TEMP_FAILURE_RETRY(statvfs(cache_filename.c_str(), &buf));
+ if (res != 0) {
+ // Could not stat. Conservatively tell the system to delete the image.
+ *error_msg = "Could not stat the filesystem, assuming low-memory situation.";
+ return false;
+ }
+
+ uint64_t fs_overall_size = buf.f_bsize * static_cast<uint64_t>(buf.f_blocks);
+ // Zygote is privileged, but other things are not. Use bavail.
+ uint64_t fs_free_size = buf.f_bsize * static_cast<uint64_t>(buf.f_bavail);
+
+ // Take the overall size as an indicator for a tmpfs, which is being used for the decryption
+ // environment. We do not want to fail quickening the boot image there, as it is beneficial
+ // for time-to-UI.
+ if (fs_overall_size > kTmpFsSentinelValue) {
+ if (fs_free_size < kLowSpaceValue) {
+ *error_msg = StringPrintf("Low-memory situation: only %4.2f megabytes available after image"
+ " generation, need at least %" PRIu64 ".",
+ static_cast<double>(fs_free_size) / MB,
+ kLowSpaceValue / MB);
+ return false;
+ }
+ }
+ return true;
+}
+
ImageSpace* ImageSpace::Create(const char* image_location,
const InstructionSet image_isa,
std::string* error_msg) {
@@ -523,6 +559,13 @@
PruneDexCache(image_isa);
return nullptr;
} else {
+ // Check whether there is enough space left over after we have generated the image.
+ if (!CheckSpace(cache_filename, error_msg)) {
+ // No. Delete the generated image and try to run out of the dex files.
+ PruneDexCache(image_isa);
+ return nullptr;
+ }
+
// Note that we must not use the file descriptor associated with
// ScopedFlock::GetFile to Init the image file. We want the file
// descriptor (and the associated exclusive lock) to be released when
