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Fix side effect of Remove operation. #2851

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Fix side effect of Remove operation. #2851

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49 changes: 30 additions & 19 deletions src/common/arc_cache.h
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Original file line number Diff line number Diff line change
Expand Up @@ -37,7 +37,7 @@ class ARCCache : public LRUCacheInterface<K, V> {
public:
ARCCache(int64_t max_count,
std::shared_ptr<CacheMetrics> cacheMetrics = nullptr)
: c_(max_count/2), p_(0), cacheMetrics_(cacheMetrics) {}
: c_(max_count), p_(0), cacheMetrics_(cacheMetrics) {}

void Put(const K& key, const V& value);
bool Put(const K& key, const V& value, V* eliminated);
Expand Down Expand Up @@ -158,7 +158,7 @@ class ARCCache : public LRUCacheInterface<K, V> {
map.erase(map_iter);
}

int Count() const { return map.size(); }
int64_t Count() const { return map.size(); }
};

struct T {
Expand Down Expand Up @@ -238,7 +238,7 @@ class ARCCache : public LRUCacheInterface<K, V> {
map_iter->second.list_iter = --list.end();
}

int Count() const { return map.size(); }
int64_t Count() const { return map.size(); }

tmap_iter GetLRU() const { return list.begin()->map_iter; }
};
Expand All @@ -262,6 +262,15 @@ class ARCCache : public LRUCacheInterface<K, V> {
return true;
}

bool IsCacheFull() const {
return t1_.count() + t2_.count() == c_;
}

void SetP(int64_t p) {
if (IsCacheFull())
p_ = p;
}

bool Replace(const K& k, V* eliminated);

::curve::common::RWLock lock_;
Expand Down Expand Up @@ -324,34 +333,22 @@ bool ARCCache<K, V, KeyTraits, ValueTraits>::Put(const K& key, const V& value,

bmap_iter b_it;
if (b1_.Find(key, &b_it)) {
if (b1_.Count() >= b2_.Count()) {
p_ += 1;
} else {
p_ += b2_.Count() / b1_.Count();
}
if (p_ > c_) p_ = c_;

SetP(std::min(c_, p_ + std::max(b2_.Count()/b1_.Count(), 1)));
ret = Replace(key, eliminated);
b1_.Remove(std::move(b_it), cacheMetrics_.get());
t2_.Insert(key, value, cacheMetrics_.get());
return ret;
}

if (b2_.Find(key, &b_it)) {
if (b2_.Count() >= b1_.Count()) {
p_ -= 1;
} else {
p_ -= b1_.Count() / b2_.Count();
}
if (p_ < 0) p_ = 0;

SetP(std::max(0, p_ - std::max(b1_.Count()/b2_.Count(), 1)));
ret = Replace(key, eliminated);
b2_.Remove(std::move(b_it), cacheMetrics_.get());
t2_.Insert(key, value, cacheMetrics_.get());
return ret;
}

if (t1_.Count() + b1_.Count() == c_) {
if (IsCacheFull() && t1_.Count() + b1_.Count() == c_) {
if (t1_.Count() < c_) {
b1_.RemoveLRU(cacheMetrics_.get());
ret = Replace(key, eliminated);
Expand All @@ -372,11 +369,16 @@ bool ARCCache<K, V, KeyTraits, ValueTraits>::Put(const K& key, const V& value,
template <typename K, typename V, typename KeyTraits, typename ValueTraits>
bool ARCCache<K, V, KeyTraits, ValueTraits>::Replace(const K& k,
V* eliminated) {
if (!IsCacheFull()) {
return false;
}
if (t1_.Count() != 0 &&
((t1_.Count() > p_) || (b2_.Find(k, nullptr) && t1_.Count() == p_))) {
return Move_T_B(&t1_, &b1_, eliminated);
} else {
} else if (t2_.Count() > 0) {
return Move_T_B(&t2_, &b2_, eliminated);
} else {
return Move_T_B(&t1_, &b1_, eliminated);
}
}

Expand All @@ -386,6 +388,7 @@ uint64_t ARCCache<K, V, KeyTraits, ValueTraits>::Size() {
return t1_.Count() + t2_.Count();
}

// This operation Detach the key from cache
template <typename K, typename V, typename KeyTraits, typename ValueTraits>
void ARCCache<K, V, KeyTraits, ValueTraits>::Remove(const K& key) {
::curve::common::WriteLockGuard guard(lock_);
Expand All @@ -397,6 +400,14 @@ void ARCCache<K, V, KeyTraits, ValueTraits>::Remove(const K& key) {
return;
}
}
B* bs[]{&b1_, &b2_};
for (auto b : bs) {
bmap_iter it;
if (b->Find(key, &it)) {
b->Remove(std::move(it), cacheMetrics_.get());
return;
}
}
}

template <typename K, typename V, typename KeyTraits, typename ValueTraits>
Expand Down