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Optimize app compaction system reduce page faults

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This patch allows for amortizing the memory churn in compaction
over time by reusing the vector and its vmas as well as sending
a preassigned buffer to fill maps. Effectively, after a compaction
run we usually see no new allocations which also reduces the page
fault cost and the allocation cost.

Bug: 243976314
Test: am compact full <processname> <uid>

Change-Id: I36e96284b72b7b03d75171058def23b783f6c5cd
This commit is contained in:
Edgar Arriaga
2023-01-13 18:24:24 +00:00
committed by Edgar Arriaga García
parent 44a29da87e
commit 2b7a8e1883
1 changed files with 40 additions and 14 deletions
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54
services/core/jni/com_android_server_am_CachedAppOptimizer.cpp
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@@ -146,6 +146,7 @@ uint64_t consumeBytes(VmaBatch& batch, uint64_t bytesToConsume) {
// vmas vector, instead it iterates on it until the end.
class VmaBatchCreator {
const std::vector<Vma>* sourceVmas;
const int totalVmasInSource;
// This is the destination array where batched VMAs will be stored
// it gets encapsulated into a VmaBatch which is the object
// meant to be used by client code.
@@ -156,8 +157,13 @@ class VmaBatchCreator {
uint64_t currentOffset_;
public:
VmaBatchCreator(const std::vector<Vma>* vmasToBatch, struct iovec* destVmasVec)
: sourceVmas(vmasToBatch), destVmas(destVmasVec), currentIndex_(0), currentOffset_(0) {}
VmaBatchCreator(const std::vector<Vma>* vmasToBatch, struct iovec* destVmasVec,
int vmasInSource)
: sourceVmas(vmasToBatch),
totalVmasInSource(vmasInSource),
destVmas(destVmasVec),
currentIndex_(0),
currentOffset_(0) {}
int currentIndex() { return currentIndex_; }
uint64_t currentOffset() { return currentOffset_; }
@@ -177,7 +183,7 @@ public:
// Add VMAs to the batch up until we consumed all the VMAs or
// reached any imposed limit of VMAs per batch.
while (indexInBatch < MAX_VMAS_PER_BATCH && currentIndex_ < vmas.size()) {
while (indexInBatch < MAX_VMAS_PER_BATCH && currentIndex_ < totalVmasInSource) {
uint64_t vmaStart = vmas[currentIndex_].start + currentOffset_;
uint64_t vmaSize = vmas[currentIndex_].end - vmaStart;
uint64_t bytesAvailableInBatch = MAX_BYTES_PER_BATCH - totalBytesInBatch;
@@ -272,8 +278,9 @@ static inline void compactProcessProcfs(int pid, const std::string& compactionTy
//
// If any VMA fails compaction due to -EINVAL it will be skipped and continue.
// However, if it fails for any other reason, it will bail out and forward the error
static int64_t compactMemory(const std::vector<Vma>& vmas, int pid, int madviseType) {
if (vmas.empty()) {
static int64_t compactMemory(const std::vector<Vma>& vmas, int pid, int madviseType,
int totalVmas) {
if (totalVmas == 0) {
return 0;
}
@@ -286,7 +293,7 @@ static int64_t compactMemory(const std::vector<Vma>& vmas, int pid, int madviseT
struct iovec destVmas[MAX_VMAS_PER_BATCH];
VmaBatch batch;
VmaBatchCreator batcher(&vmas, destVmas);
VmaBatchCreator batcher(&vmas, destVmas, totalVmas);
int64_t totalBytesProcessed = 0;
while (batcher.createNextBatch(batch)) {
@@ -346,34 +353,53 @@ static int getAnyPageAdvice(const Vma& vma) {
// Returns the total number of bytes compacted on success. On error
// returns process_madvise errno code or if compaction was cancelled
// it returns ERROR_COMPACTION_CANCELLED.
//
// Not thread safe. We reuse vectors so we assume this is called only
// on one thread at most.
static int64_t compactProcess(int pid, VmaToAdviseFunc vmaToAdviseFunc) {
cancelRunningCompaction.store(false);
static std::string mapsBuffer;
ATRACE_BEGIN("CollectVmas");
ProcMemInfo meminfo(pid);
std::vector<Vma> pageoutVmas, coldVmas;
auto vmaCollectorCb = [&coldVmas,&pageoutVmas,&vmaToAdviseFunc](const Vma& vma) {
static std::vector<Vma> pageoutVmas(2000), coldVmas(2000);
int coldVmaIndex = 0;
int pageoutVmaIndex = 0;
auto vmaCollectorCb = [&vmaToAdviseFunc, &pageoutVmaIndex, &coldVmaIndex](const Vma& vma) {
int advice = vmaToAdviseFunc(vma);
switch (advice) {
case MADV_COLD:
coldVmas.push_back(vma);
if (coldVmaIndex < coldVmas.size()) {
coldVmas[coldVmaIndex] = vma;
} else {
coldVmas.push_back(vma);
}
++coldVmaIndex;
break;
case MADV_PAGEOUT:
pageoutVmas.push_back(vma);
if (pageoutVmaIndex < pageoutVmas.size()) {
pageoutVmas[pageoutVmaIndex] = vma;
} else {
pageoutVmas.push_back(vma);
}
++pageoutVmaIndex;
break;
}
};
meminfo.ForEachVmaFromMaps(vmaCollectorCb);
meminfo.ForEachVmaFromMaps(vmaCollectorCb, mapsBuffer);
ATRACE_END();
#ifdef DEBUG_COMPACTION
ALOGE("Total VMAs sent for compaction anon=%d file=%d", pageoutVmaIndex,
coldVmaIndex);
#endif
int64_t pageoutBytes = compactMemory(pageoutVmas, pid, MADV_PAGEOUT);
int64_t pageoutBytes = compactMemory(pageoutVmas, pid, MADV_PAGEOUT, pageoutVmaIndex);
if (pageoutBytes < 0) {
// Error, just forward it.
cancelRunningCompaction.store(false);
return pageoutBytes;
}
int64_t coldBytes = compactMemory(coldVmas, pid, MADV_COLD);
int64_t coldBytes = compactMemory(coldVmas, pid, MADV_COLD, coldVmaIndex);
if (coldBytes < 0) {
// Error, just forward it.
cancelRunningCompaction.store(false);