Merge "Revert "Resend remaining VMAs on partial compaction due to failure"" into tm-dev am: 118798375d
Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18174406 Change-Id: I3283f3d367a775ae68e8378b266e37a9c042ef93 Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
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@@ -66,13 +66,13 @@ using android::base::unique_fd;
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// Defines the maximum amount of VMAs we can send per process_madvise syscall.
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// Currently this is set to UIO_MAXIOV which is the maximum segments allowed by
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// iovec implementation used by process_madvise syscall
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#define MAX_VMAS_PER_BATCH UIO_MAXIOV
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#define MAX_VMAS_PER_COMPACTION UIO_MAXIOV
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// Maximum bytes that we can send per process_madvise syscall once this limit
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// is reached we split the remaining VMAs into another syscall. The MAX_RW_COUNT
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// limit is imposed by iovec implementation. However, if you want to use a smaller
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// limit, it has to be a page aligned value.
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#define MAX_BYTES_PER_BATCH MAX_RW_COUNT
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// limit, it has to be a page aligned value, otherwise, compaction would fail.
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#define MAX_BYTES_PER_COMPACTION MAX_RW_COUNT
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// Selected a high enough number to avoid clashing with linux errno codes
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#define ERROR_COMPACTION_CANCELLED -1000
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@@ -83,181 +83,6 @@ namespace android {
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// before starting next VMA batch
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static std::atomic<bool> cancelRunningCompaction;
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// A VmaBatch represents a set of VMAs that can be processed
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// as VMAs are processed by client code it is expected that the
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// VMAs get consumed which means they are discarded as they are
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// processed so that the first element always is the next element
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// to be sent
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struct VmaBatch {
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struct iovec* vmas;
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// total amount of VMAs to reach the end of iovec
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int totalVmas;
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// total amount of bytes that are remaining within iovec
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uint64_t totalBytes;
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};
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// Advances the iterator by the specified amount of bytes.
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// This is used to remove already processed or no longer
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// needed parts of the batch.
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// Returns total bytes consumed
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int consumeBytes(VmaBatch& batch, uint64_t bytesToConsume) {
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int index = 0;
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if (CC_UNLIKELY(bytesToConsume) < 0) {
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LOG(ERROR) << "Cannot consume negative bytes for VMA batch !";
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return 0;
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}
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if (bytesToConsume > batch.totalBytes) {
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// Avoid consuming more bytes than available
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bytesToConsume = batch.totalBytes;
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}
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uint64_t bytesConsumed = 0;
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while (bytesConsumed < bytesToConsume) {
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if (CC_UNLIKELY(index >= batch.totalVmas)) {
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// reach the end of the batch
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return bytesConsumed;
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}
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if (CC_UNLIKELY(bytesConsumed + batch.vmas[index].iov_len > bytesToConsume)) {
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// this is the whole VMA that will be consumed
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break;
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}
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bytesConsumed += batch.vmas[index].iov_len;
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batch.totalBytes -= batch.vmas[index].iov_len;
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--batch.totalVmas;
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++index;
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}
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// Move pointer to consume all the whole VMAs
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batch.vmas = batch.vmas + index;
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// Consume the rest of the bytes partially at last VMA in batch
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uint64_t bytesLeftToConsume = bytesToConsume - bytesConsumed;
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bytesConsumed += bytesLeftToConsume;
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if (batch.totalVmas > 0) {
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batch.vmas[0].iov_base = (void*)((uint64_t)batch.vmas[0].iov_base + bytesLeftToConsume);
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}
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return bytesConsumed;
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}
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// given a source of vmas this class will act as a factory
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// of VmaBatch objects and it will allow generating batches
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// until there are no more left in the source vector.
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// Note: the class does not actually modify the given
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// vmas vector, instead it iterates on it until the end.
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class VmaBatchCreator {
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const std::vector<Vma>* sourceVmas;
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// This is the destination array where batched VMAs will be stored
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// it gets encapsulated into a VmaBatch which is the object
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// meant to be used by client code.
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struct iovec* destVmas;
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// Parameters to keep track of the iterator on the source vmas
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int currentIndex_;
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uint64_t currentOffset_;
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public:
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VmaBatchCreator(const std::vector<Vma>* vmasToBatch, struct iovec* destVmasVec)
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: sourceVmas(vmasToBatch), destVmas(destVmasVec), currentIndex_(0), currentOffset_(0) {}
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int currentIndex() { return currentIndex_; }
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uint64_t currentOffset() { return currentOffset_; }
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// Generates a batch and moves the iterator on the source vmas
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// past the last VMA in the batch.
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// Returns true on success, false on failure
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bool createNextBatch(VmaBatch& batch) {
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if (currentIndex_ >= MAX_VMAS_PER_BATCH && currentIndex_ >= sourceVmas->size()) {
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return false;
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}
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const std::vector<Vma>& vmas = *sourceVmas;
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batch.vmas = destVmas;
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uint64_t totalBytesInBatch = 0;
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int indexInBatch = 0;
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// Add VMAs to the batch up until we consumed all the VMAs or
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// reached any imposed limit of VMAs per batch.
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while (indexInBatch < MAX_VMAS_PER_BATCH && currentIndex_ < vmas.size()) {
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uint64_t vmaStart = vmas[currentIndex_].start + currentOffset_;
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uint64_t vmaSize = vmas[currentIndex_].end - vmaStart;
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if (CC_UNLIKELY(vmaSize == 0)) {
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// No more bytes to batch for this VMA, move to next one
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// this only happens if a batch partially consumed bytes
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// and offset landed at exactly the end of a vma
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continue;
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}
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batch.vmas[indexInBatch].iov_base = (void*)vmaStart;
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uint64_t bytesAvailableInBatch = MAX_BYTES_PER_BATCH - totalBytesInBatch;
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if (vmaSize >= bytesAvailableInBatch) {
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// VMA would exceed the max available bytes in batch
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// clamp with available bytes and finish batch.
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vmaSize = bytesAvailableInBatch;
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currentOffset_ += bytesAvailableInBatch;
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}
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batch.vmas[indexInBatch].iov_len = vmaSize;
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totalBytesInBatch += vmaSize;
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++indexInBatch;
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if (totalBytesInBatch >= MAX_BYTES_PER_BATCH) {
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// Reached max bytes quota so this marks
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// the end of the batch
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break;
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}
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// Fully finished current VMA, move to next one
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currentOffset_ = 0;
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++currentIndex_;
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}
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// Vmas where fully filled and we are past the last filled index.
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batch.totalVmas = indexInBatch;
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batch.totalBytes = totalBytesInBatch;
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return true;
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}
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};
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// Madvise a set of VMAs given in a batch for a specific process
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// The total number of bytes successfully madvised will be set on
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// outBytesProcessed.
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// Returns 0 on success and standard linux -errno code returned by
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// process_madvise on failure
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int madviseVmasFromBatch(unique_fd& pidfd, VmaBatch& batch, int madviseType,
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uint64_t* outBytesProcessed) {
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if (batch.totalVmas == 0) {
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// No VMAs in Batch, skip.
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*outBytesProcessed = 0;
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return 0;
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}
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ATRACE_BEGIN(StringPrintf("Madvise %d: %d VMAs", madviseType, batch.totalVmas).c_str());
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uint64_t bytesProcessedInSend =
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process_madvise(pidfd, batch.vmas, batch.totalVmas, madviseType, 0);
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ATRACE_END();
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if (CC_UNLIKELY(bytesProcessedInSend == -1)) {
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bytesProcessedInSend = 0;
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if (errno != EINVAL) {
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// Forward irrecoverable errors and bail out compaction
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*outBytesProcessed = 0;
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return -errno;
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}
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}
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if (bytesProcessedInSend < batch.totalBytes) {
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// Did not process all the bytes requested
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// skip last page which likely failed
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bytesProcessedInSend += PAGE_SIZE;
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}
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bytesProcessedInSend = consumeBytes(batch, bytesProcessedInSend);
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*outBytesProcessed = bytesProcessedInSend;
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return 0;
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}
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// Legacy method for compacting processes, any new code should
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// use compactProcess instead.
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static inline void compactProcessProcfs(int pid, const std::string& compactionType) {
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@@ -271,6 +96,8 @@ static inline void compactProcessProcfs(int pid, const std::string& compactionTy
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// If any VMA fails compaction due to -EINVAL it will be skipped and continue.
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// However, if it fails for any other reason, it will bail out and forward the error
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static int64_t compactMemory(const std::vector<Vma>& vmas, int pid, int madviseType) {
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static struct iovec vmasToKernel[MAX_VMAS_PER_COMPACTION];
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if (vmas.empty()) {
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return 0;
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}
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@@ -281,16 +108,13 @@ static int64_t compactMemory(const std::vector<Vma>& vmas, int pid, int madviseT
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return -errno;
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}
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struct iovec destVmas[MAX_VMAS_PER_BATCH];
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VmaBatch batch;
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VmaBatchCreator batcher(&vmas, destVmas);
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int64_t totalBytesProcessed = 0;
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while (batcher.createNextBatch(batch)) {
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uint64_t bytesProcessedInSend;
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do {
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int64_t vmaOffset = 0;
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for (int iVma = 0; iVma < vmas.size();) {
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uint64_t bytesSentToCompact = 0;
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int iVec = 0;
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while (iVec < MAX_VMAS_PER_COMPACTION && iVma < vmas.size()) {
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if (CC_UNLIKELY(cancelRunningCompaction.load())) {
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// There could be a significant delay between when a compaction
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// is requested and when it is handled during this time our
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@@ -300,13 +124,50 @@ static int64_t compactMemory(const std::vector<Vma>& vmas, int pid, int madviseT
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StringPrintf("Cancelled compaction for %d", pid).c_str());
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return ERROR_COMPACTION_CANCELLED;
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}
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int error = madviseVmasFromBatch(pidfd, batch, madviseType, &bytesProcessedInSend);
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if (error < 0) {
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// Returns standard linux errno code
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return error;
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uint64_t vmaStart = vmas[iVma].start + vmaOffset;
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uint64_t vmaSize = vmas[iVma].end - vmaStart;
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if (vmaSize == 0) {
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goto next_vma;
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}
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totalBytesProcessed += bytesProcessedInSend;
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} while (batch.totalBytes > 0);
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vmasToKernel[iVec].iov_base = (void*)vmaStart;
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if (vmaSize > MAX_BYTES_PER_COMPACTION - bytesSentToCompact) {
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// Exceeded the max bytes that could be sent, so clamp
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// the end to avoid exceeding limit and issue compaction
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vmaSize = MAX_BYTES_PER_COMPACTION - bytesSentToCompact;
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}
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vmasToKernel[iVec].iov_len = vmaSize;
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bytesSentToCompact += vmaSize;
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++iVec;
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if (bytesSentToCompact >= MAX_BYTES_PER_COMPACTION) {
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// Ran out of bytes within iovec, dispatch compaction.
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vmaOffset += vmaSize;
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break;
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}
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next_vma:
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// Finished current VMA, and have more bytes remaining
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vmaOffset = 0;
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++iVma;
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}
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ATRACE_BEGIN(StringPrintf("Compact %d VMAs", iVec).c_str());
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auto bytesProcessed = process_madvise(pidfd, vmasToKernel, iVec, madviseType, 0);
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ATRACE_END();
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if (CC_UNLIKELY(bytesProcessed == -1)) {
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if (errno == EINVAL) {
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// This error is somewhat common due to an unevictable VMA if this is
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// the case silently skip the bad VMA and continue compacting the rest.
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continue;
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} else {
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// Forward irrecoverable errors and bail out compaction
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return -errno;
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}
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}
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totalBytesProcessed += bytesProcessed;
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}
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return totalBytesProcessed;
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