validate canons without yatest_common

24 files changed, 2216 insertions, 0 deletions

diff --git a/library/cpp/yt/containers/sharded_set-inl.h b/library/cpp/yt/containers/sharded_set-inl.h
new file mode 100644
index 00000000000..67d5be58c62
--- /dev/null
+++ b/library/cpp/yt/containers/sharded_set-inl.h
@@ -0,0 +1,217 @@
+#ifndef SHARDED_SET_INL_H_
+#error "Direct inclusion of this file is not allowed, include sharded_set.h"
+// For the sake of sane code completion.
+#include "sharded_set.h"
+#endif
+
+#include <library/cpp/yt/assert/assert.h>
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+template <class T, int N, class F, class S>
+class TShardedSet<T, N, F, S>::const_iterator
+{
+private:
+    friend class TShardedSet<T, N, F, S>;
+
+    using TOwner = TShardedSet<T, N, F, S>;
+    using TShardIterator = typename S::const_iterator;
+
+    const TOwner* const Owner_;
+
+    int ShardIndex_;
+    TShardIterator ShardIterator_;
+
+    const_iterator(
+        const TOwner* owner,
+        int shardIndex,
+        TShardIterator shardIterator)
+        : Owner_(owner)
+        , ShardIndex_(shardIndex)
+        , ShardIterator_(shardIterator)
+    { }
+
+    bool IsValid() const
+    {
+        return ShardIterator_ != Owner_->Shards_[ShardIndex_].end();
+    }
+
+    void FastForward()
+    {
+        while (ShardIndex_ != N - 1 && !IsValid()) {
+            ++ShardIndex_;
+            ShardIterator_ = Owner_->Shards_[ShardIndex_].begin();
+        }
+    }
+
+public:
+    using difference_type = typename std::iterator_traits<TShardIterator>::difference_type;
+    using value_type = typename std::iterator_traits<TShardIterator>::value_type;
+    using pointer = typename std::iterator_traits<TShardIterator>::pointer;
+    using reference = typename std::iterator_traits<TShardIterator>::reference;
+    using iterator_category = std::forward_iterator_tag;
+
+    const_iterator& operator++()
+    {
+        ++ShardIterator_;
+        FastForward();
+
+        return *this;
+    }
+
+    const_iterator operator++(int)
+    {
+        auto result = *this;
+
+        ++ShardIterator_;
+        FastForward();
+
+        return result;
+    }
+
+    bool operator==(const const_iterator& rhs) const
+    {
+        return
+            ShardIndex_ == rhs.ShardIndex_ &&
+            ShardIterator_ == rhs.ShardIterator_;
+    }
+
+    bool operator!=(const const_iterator& rhs) const
+    {
+        return !(*this == rhs);
+    }
+
+    const T& operator*() const
+    {
+        return *ShardIterator_;
+    }
+
+    const T* operator->() const
+    {
+        return &operator*();
+    }
+};
+
+////////////////////////////////////////////////////////////////////////////////
+
+template <class T, int N, class F, class S>
+TShardedSet<T, N, F, S>::TShardedSet(F elementToShard)
+    : ElementToShard_(elementToShard)
+{ }
+
+template <class T, int N, class F, class S>
+bool TShardedSet<T, N, F, S>::empty() const
+{
+    return size() == 0;
+}
+
+template <class T, int N, class F, class S>
+typename TShardedSet<T, N, F, S>::size_type TShardedSet<T, N, F, S>::size() const
+{
+    size_type result = 0;
+    for (const auto& shard : Shards_) {
+        result += shard.size();
+    }
+
+    return result;
+}
+
+template <class T, int N, class F, class S>
+const T& TShardedSet<T, N, F, S>::front() const
+{
+    return *begin();
+}
+
+template <class T, int N, class F, class S>
+typename TShardedSet<T, N, F, S>::size_type TShardedSet<T, N, F, S>::count(const T& value) const
+{
+    return GetShard(value).count(value);
+}
+
+template <class T, int N, class F, class S>
+bool TShardedSet<T, N, F, S>::contains(const T& value) const
+{
+    return GetShard(value).contains(value);
+}
+
+template <class T, int N, class F, class S>
+std::pair<typename TShardedSet<T, N, F, S>::const_iterator, bool> TShardedSet<T, N, F, S>::insert(const T& value)
+{
+    auto shardIndex = ElementToShard_(value);
+    auto& shard = Shards_[shardIndex];
+    auto [shardIterator, inserted] = shard.insert(value);
+
+    const_iterator iterator(this, shardIndex, shardIterator);
+    return {iterator, inserted};
+}
+
+template <class T, int N, class F, class S>
+bool TShardedSet<T, N, F, S>::erase(const T& value)
+{
+    return GetShard(value).erase(value);
+}
+
+template <class T, int N, class F, class S>
+void TShardedSet<T, N, F, S>::clear()
+{
+    for (auto& shard : Shards_) {
+        shard.clear();
+    }
+}
+
+template <class T, int N, class F, class S>
+typename TShardedSet<T, N, F, S>::const_iterator TShardedSet<T, N, F, S>::begin() const
+{
+    const_iterator iterator(this, /*shardIndex*/ 0, /*shardIterator*/ Shards_[0].begin());
+    iterator.FastForward();
+
+    return iterator;
+}
+
+template <class T, int N, class F, class S>
+typename TShardedSet<T, N, F, S>::const_iterator TShardedSet<T, N, F, S>::cbegin() const
+{
+    return begin();
+}
+
+template <class T, int N, class F, class S>
+typename TShardedSet<T, N, F, S>::const_iterator TShardedSet<T, N, F, S>::end() const
+{
+    return const_iterator(this, /*shardIndex*/ N - 1, /*shardIterator*/ Shards_[N - 1].end());
+}
+
+template <class T, int N, class F, class S>
+typename TShardedSet<T, N, F, S>::const_iterator TShardedSet<T, N, F, S>::cend() const
+{
+    return end();
+}
+
+template <class T, int N, class F, class S>
+const S& TShardedSet<T, N, F, S>::Shard(int shardIndex) const
+{
+    return Shards_[shardIndex];
+}
+
+template <class T, int N, class F, class S>
+S& TShardedSet<T, N, F, S>::MutableShard(int shardIndex)
+{
+    return Shards_[shardIndex];
+}
+
+template <class T, int N, class F, class S>
+S& TShardedSet<T, N, F, S>::GetShard(const T& value)
+{
+    return Shards_[ElementToShard_(value)];
+}
+
+template <class T, int N, class F, class S>
+const S& TShardedSet<T, N, F, S>::GetShard(const T& value) const
+{
+    return Shards_[ElementToShard_(value)];
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
diff --git a/library/cpp/yt/containers/sharded_set.h b/library/cpp/yt/containers/sharded_set.h
new file mode 100644
index 00000000000..fa24893aa44
--- /dev/null
+++ b/library/cpp/yt/containers/sharded_set.h
@@ -0,0 +1,69 @@
+#pragma once
+
+#include <util/generic/hash_set.h>
+
+#include <array>
+#include <cstddef>
+#include <utility>
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+//! A set that stores elements divided into fixed amount of shards.
+//! Provides access to whole set and particular shards.
+//! The interface is pretty minimalistic, feel free to extend it when needed.
+template <class T, int N, class F, class S = THashSet<T>>
+class TShardedSet
+{
+public:
+    using size_type = size_t;
+    using difference_type = ptrdiff_t;
+
+    using value_type = T;
+
+    class const_iterator;
+
+    explicit TShardedSet(F elementToShard = F());
+
+    [[nodiscard]] bool empty() const;
+
+    size_type size() const;
+
+    const T& front() const;
+
+    size_type count(const T& value) const;
+
+    bool contains(const T& value) const;
+
+    std::pair<const_iterator, bool> insert(const T& value);
+
+    bool erase(const T& value);
+
+    void clear();
+
+    const_iterator begin() const;
+    const_iterator cbegin() const;
+
+    const_iterator end() const;
+    const_iterator cend() const;
+
+    const S& Shard(int shardIndex) const;
+    S& MutableShard(int shardIndex);
+
+private:
+    std::array<S, N> Shards_;
+
+    const F ElementToShard_;
+
+    S& GetShard(const T& value);
+    const S& GetShard(const T& value) const;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
+
+#define SHARDED_SET_INL_H_
+#include "sharded_set-inl.h"
+#undef SHARDED_SET_INL_H_
diff --git a/library/cpp/yt/containers/unittests/sharded_set_ut.cpp b/library/cpp/yt/containers/unittests/sharded_set_ut.cpp
new file mode 100644
index 00000000000..2c4f8c59356
--- /dev/null
+++ b/library/cpp/yt/containers/unittests/sharded_set_ut.cpp
@@ -0,0 +1,121 @@
+#include <library/cpp/yt/containers/sharded_set.h>
+
+#include <library/cpp/testing/gtest/gtest.h>
+
+#include <random>
+
+namespace NYT {
+namespace {
+
+////////////////////////////////////////////////////////////////////////////////
+
+struct TIntToShard
+{
+    int operator()(int value) const
+    {
+        return value % 16;
+    }
+};
+
+using TSet = TShardedSet<int, 16, TIntToShard>;
+
+////////////////////////////////////////////////////////////////////////////////
+
+TEST(CompactSetTest, Insert)
+{
+    TSet set;
+
+    for (int i = 0; i < 4; i++) {
+        set.insert(i);
+    }
+
+    for (int i = 0; i < 4; i++) {
+        set.insert(i);
+    }
+
+    EXPECT_EQ(4u, set.size());
+
+    for (int i = 0; i < 4; i++)
+    EXPECT_EQ(1u, set.count(i));
+
+    EXPECT_EQ(0u, set.count(4));
+}
+
+TEST(CompactSetTest, Erase)
+{
+    TSet set;
+
+    for (int i = 0; i < 8; i++) {
+        set.insert(i);
+    }
+
+    EXPECT_EQ(8u, set.size());
+
+    // Remove elements one by one and check if all other elements are still there.
+    for (int i = 0; i < 8; i++) {
+        EXPECT_EQ(1u, set.count(i));
+        EXPECT_TRUE(set.erase(i));
+        EXPECT_EQ(0u, set.count(i));
+        EXPECT_EQ(8u - i - 1, set.size());
+        for (int j = i + 1; j < 8; j++) {
+            EXPECT_EQ(1u, set.count(j));
+        }
+    }
+
+    EXPECT_EQ(0u, set.count(8));
+}
+
+TEST(CompactSetTest, StressTest)
+{
+    TSet set;
+
+    constexpr int Iterations = 1'000'000;
+    constexpr int Values = 128;
+
+    THashSet<int> values;
+
+    auto checkEverything = [&] {
+        EXPECT_EQ(values.size(), set.size());
+        EXPECT_EQ(values.empty(), set.empty());
+        EXPECT_EQ(values, THashSet<int>(set.begin(), set.end()));
+
+        std::array<THashSet<int>, 16> shards;
+        for (int value : values) {
+            shards[value % 16].insert(value);
+        }
+        for (int shardIndex = 0; shardIndex < 16; ++shardIndex) {
+            EXPECT_EQ(shards[shardIndex], set.Shard(shardIndex));
+        }
+
+        for (int value = 0; value < Values; ++value) {
+            EXPECT_EQ(values.contains(value), set.contains(value));
+            EXPECT_EQ(values.count(value), set.count(value));
+        }
+    };
+
+    std::mt19937_64 rng(42);
+
+    for (int iteration = 0; iteration < Iterations; ++iteration) {
+        if (rng() % 100 == 0) {
+            set.clear();
+            values.clear();
+            checkEverything();
+        }
+
+        int value = rng() % Values;
+        if (rng() % 2 == 0) {
+            set.insert(value);
+            values.insert(value);
+        } else {
+            set.erase(value);
+            values.erase(value);
+        }
+
+        checkEverything();
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace
+} // namespace NYT
diff --git a/library/cpp/yt/cpu_clock/benchmark/benchmark.cpp b/library/cpp/yt/cpu_clock/benchmark/benchmark.cpp
new file mode 100644
index 00000000000..e326da68379
--- /dev/null
+++ b/library/cpp/yt/cpu_clock/benchmark/benchmark.cpp
@@ -0,0 +1,32 @@
+#include "benchmark/benchmark.h"
+#include <benchmark/benchmark.h>
+
+#include <library/cpp/yt/cpu_clock/clock.h>
+
+namespace NYT {
+namespace {
+
+////////////////////////////////////////////////////////////////////////////////
+
+void BenchmarkCpuTime(benchmark::State& state)
+{
+    for (auto _ : state) {
+        benchmark::DoNotOptimize(GetCpuInstant());
+    }
+}
+
+BENCHMARK(BenchmarkCpuTime);
+
+void BenchmarkInstantNow(benchmark::State& state)
+{
+    for (auto _ : state) {
+        benchmark::DoNotOptimize(TInstant::Now());
+    }
+}
+
+BENCHMARK(BenchmarkInstantNow);
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace
+} // namespace NYT
diff --git a/library/cpp/yt/cpu_clock/unittests/clock_ut.cpp b/library/cpp/yt/cpu_clock/unittests/clock_ut.cpp
new file mode 100644
index 00000000000..bd9cb6d4be1
--- /dev/null
+++ b/library/cpp/yt/cpu_clock/unittests/clock_ut.cpp
@@ -0,0 +1,46 @@
+#include <gtest/gtest.h>
+
+#include <library/cpp/yt/cpu_clock/clock.h>
+
+namespace NYT {
+namespace {
+
+////////////////////////////////////////////////////////////////////////////////
+
+template <class T>
+i64 DiffMS(T a, T b)
+{
+    return a >= b
+        ? static_cast<i64>(a.MilliSeconds()) - static_cast<i64>(b.MilliSeconds())
+        : DiffMS(b, a);
+}
+
+TEST(TTimingTest, GetInstant)
+{
+    GetInstant();
+
+    EXPECT_LE(DiffMS(GetInstant(), TInstant::Now()), 10);
+}
+
+TEST(TTimingTest, InstantVSCpuInstant)
+{
+    auto instant1 = TInstant::Now();
+    auto cpuInstant = InstantToCpuInstant(instant1);
+    auto instant2 = CpuInstantToInstant(cpuInstant);
+    EXPECT_LE(DiffMS(instant1, instant2), 10);
+}
+
+TEST(TTimingTest, DurationVSCpuDuration)
+{
+    auto cpuInstant1 = GetCpuInstant();
+    constexpr auto duration1 = TDuration::MilliSeconds(100);
+    Sleep(duration1);
+    auto cpuInstant2 = GetCpuInstant();
+    auto duration2 = CpuDurationToDuration(cpuInstant2 - cpuInstant1);
+    EXPECT_LE(DiffMS(duration1, duration2), 10);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace
+} // namespace NYT
diff --git a/library/cpp/yt/farmhash/farm_hash.h b/library/cpp/yt/farmhash/farm_hash.h
new file mode 100644
index 00000000000..fe4c8193a0a
--- /dev/null
+++ b/library/cpp/yt/farmhash/farm_hash.h
@@ -0,0 +1,63 @@
+#pragma once
+
+#include <contrib/libs/farmhash/farmhash.h>
+
+#include <util/system/types.h>
+
+#include <util/generic/strbuf.h>
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+using TFingerprint = ui64;
+
+static inline TFingerprint FarmHash(ui64 value)
+{
+    return ::util::Fingerprint(value);
+}
+
+static inline TFingerprint FarmHash(const void* buf, size_t len)
+{
+    return ::util::Hash64(static_cast<const char*>(buf), len);
+}
+
+static inline TFingerprint FarmHash(const void* buf, size_t len, ui64 seed)
+{
+    return ::util::Hash64WithSeed(static_cast<const char*>(buf), len, seed);
+}
+
+static inline TFingerprint FarmFingerprint(ui64 value)
+{
+    return ::util::Fingerprint(value);
+}
+
+static inline TFingerprint FarmFingerprint(const void* buf, size_t len)
+{
+    return ::util::Fingerprint64(static_cast<const char*>(buf), len);
+}
+
+static inline TFingerprint FarmFingerprint(TStringBuf buf)
+{
+    return FarmFingerprint(buf.Data(), buf.Size());
+}
+
+static inline TFingerprint FarmFingerprint(ui64 first, ui64 second)
+{
+    return ::util::Fingerprint(::util::Uint128(first, second));
+}
+
+// Forever-fixed Google FarmHash fingerprint.
+template <class T>
+TFingerprint FarmFingerprint(const T* begin, const T* end)
+{
+    ui64 result = 0xdeadc0de;
+    for (const auto* value = begin; value < end; ++value) {
+        result = FarmFingerprint(result, FarmFingerprint(*value));
+    }
+    return result ^ (end - begin);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
diff --git a/library/cpp/yt/logging/logger-inl.h b/library/cpp/yt/logging/logger-inl.h
new file mode 100644
index 00000000000..6118aa00476
--- /dev/null
+++ b/library/cpp/yt/logging/logger-inl.h
@@ -0,0 +1,296 @@
+#ifndef LOGGER_INL_H_
+#error "Direct inclusion of this file is not allowed, include logger.h"
+// For the sake of sane code completion.
+#include "logger.h"
+#endif
+#undef LOGGER_INL_H_
+
+#include <library/cpp/yt/yson_string/convert.h>
+#include <library/cpp/yt/yson_string/string.h>
+
+namespace NYT::NLogging {
+
+////////////////////////////////////////////////////////////////////////////////
+
+inline bool TLogger::IsAnchorUpToDate(const TLoggingAnchor& position) const
+{
+    return
+        !Category_ ||
+        position.CurrentVersion == Category_->ActualVersion->load(std::memory_order::relaxed);
+}
+
+template <class... TArgs>
+void TLogger::AddTag(const char* format, TArgs&&... args)
+{
+    AddRawTag(Format(format, std::forward<TArgs>(args)...));
+}
+
+template <class TType>
+void TLogger::AddStructuredTag(TStringBuf key, TType value)
+{
+    StructuredTags_.emplace_back(key, NYson::ConvertToYsonString(value));
+}
+
+template <class... TArgs>
+TLogger TLogger::WithTag(const char* format, TArgs&&... args) const
+{
+    auto result = *this;
+    result.AddTag(format, std::forward<TArgs>(args)...);
+    return result;
+}
+
+template <class TType>
+TLogger TLogger::WithStructuredTag(TStringBuf key, TType value) const
+{
+    auto result = *this;
+    result.AddStructuredTag(key, value);
+    return result;
+}
+
+Y_FORCE_INLINE bool TLogger::IsLevelEnabled(ELogLevel level) const
+{
+    // This is the first check which is intended to be inlined next to
+    // logging invocation point. Check below is almost zero-cost due
+    // to branch prediction (which requires inlining for proper work).
+    if (level < MinLevel_) {
+        return false;
+    }
+
+    // Next check is heavier and requires full log manager definition which
+    // is undesirable in -inl.h header file. This is why we extract it
+    // to a separate method which is implemented in cpp file.
+    return IsLevelEnabledHeavy(level);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+namespace NDetail {
+
+struct TMessageStringBuilderContext
+{
+    TSharedMutableRef Chunk;
+};
+
+struct TMessageBufferTag
+{ };
+
+class TMessageStringBuilder
+    : public TStringBuilderBase
+{
+public:
+    TSharedRef Flush();
+
+    // For testing only.
+    static void DisablePerThreadCache();
+
+protected:
+    void DoReset() override;
+    void DoReserve(size_t newLength) override;
+
+private:
+    struct TPerThreadCache
+    {
+        ~TPerThreadCache();
+
+        TSharedMutableRef Chunk;
+        size_t ChunkOffset = 0;
+    };
+
+    TSharedMutableRef Buffer_;
+
+    static thread_local TPerThreadCache* Cache_;
+    static thread_local bool CacheDestroyed_;
+    static TPerThreadCache* GetCache();
+
+    static constexpr size_t ChunkSize = 128_KB - 64;
+};
+
+inline bool HasMessageTags(
+    const TLoggingContext& loggingContext,
+    const TLogger& logger)
+{
+    if (logger.GetTag()) {
+        return true;
+    }
+    if (loggingContext.TraceLoggingTag) {
+        return true;
+    }
+    return false;
+}
+
+inline void AppendMessageTags(
+    TStringBuilderBase* builder,
+    const TLoggingContext& loggingContext,
+    const TLogger& logger)
+{
+    bool printComma = false;
+    if (const auto& loggerTag = logger.GetTag()) {
+        builder->AppendString(loggerTag);
+        printComma = true;
+    }
+    if (auto traceLoggingTag = loggingContext.TraceLoggingTag) {
+        if (printComma) {
+            builder->AppendString(TStringBuf(", "));
+        }
+        builder->AppendString(traceLoggingTag);
+    }
+}
+
+inline void AppendLogMessage(
+    TStringBuilderBase* builder,
+    const TLoggingContext& loggingContext,
+    const TLogger& logger,
+    TRef message)
+{
+    if (HasMessageTags(loggingContext, logger)) {
+        if (message.Size() >= 1 && message[message.Size() - 1] == ')') {
+            builder->AppendString(TStringBuf(message.Begin(), message.Size() - 1));
+            builder->AppendString(TStringBuf(", "));
+        } else {
+            builder->AppendString(TStringBuf(message.Begin(), message.Size()));
+            builder->AppendString(TStringBuf(" ("));
+        }
+        AppendMessageTags(builder, loggingContext, logger);
+        builder->AppendChar(')');
+    } else {
+        builder->AppendString(TStringBuf(message.Begin(), message.Size()));
+    }
+}
+
+template <class... TArgs>
+void AppendLogMessageWithFormat(
+    TStringBuilderBase* builder,
+    const TLoggingContext& loggingContext,
+    const TLogger& logger,
+    TStringBuf format,
+    TArgs&&... args)
+{
+    if (HasMessageTags(loggingContext, logger)) {
+        if (format.size() >= 2 && format[format.size() - 1] == ')') {
+            builder->AppendFormat(format.substr(0, format.size() - 1), std::forward<TArgs>(args)...);
+            builder->AppendString(TStringBuf(", "));
+        } else {
+            builder->AppendFormat(format, std::forward<TArgs>(args)...);
+            builder->AppendString(TStringBuf(" ("));
+        }
+        AppendMessageTags(builder, loggingContext, logger);
+        builder->AppendChar(')');
+    } else {
+        builder->AppendFormat(format, std::forward<TArgs>(args)...);
+    }
+}
+
+struct TLogMessage
+{
+    TSharedRef MessageRef;
+    TStringBuf Anchor;
+};
+
+template <size_t Length, class... TArgs>
+TLogMessage BuildLogMessage(
+    const TLoggingContext& loggingContext,
+    const TLogger& logger,
+    const char (&format)[Length],
+    TArgs&&... args)
+{
+    TMessageStringBuilder builder;
+    AppendLogMessageWithFormat(&builder, loggingContext, logger, format, std::forward<TArgs>(args)...);
+    return {builder.Flush(), format};
+}
+
+template <class T>
+TLogMessage BuildLogMessage(
+    const TLoggingContext& loggingContext,
+    const TLogger& logger,
+    const T& obj)
+{
+    TMessageStringBuilder builder;
+    FormatValue(&builder, obj, TStringBuf());
+    if (HasMessageTags(loggingContext, logger)) {
+        builder.AppendString(TStringBuf(" ("));
+        AppendMessageTags(&builder, loggingContext, logger);
+        builder.AppendChar(')');
+    }
+    return {builder.Flush(), TStringBuf()};
+}
+
+inline TLogMessage BuildLogMessage(
+    const TLoggingContext& loggingContext,
+    const TLogger& logger,
+    TStringBuf message)
+{
+    TMessageStringBuilder builder;
+    builder.AppendString(message);
+    if (HasMessageTags(loggingContext, logger)) {
+        builder.AppendString(TStringBuf(" ("));
+        AppendMessageTags(&builder, loggingContext, logger);
+        builder.AppendChar(')');
+    }
+    return {builder.Flush(), message};
+}
+
+template <size_t Length>
+TLogMessage BuildLogMessage(
+    const TLoggingContext& loggingContext,
+    const TLogger& logger,
+    const char (&message)[Length])
+{
+    return BuildLogMessage(
+        loggingContext,
+        logger,
+        TStringBuf(message));
+}
+
+inline TLogMessage BuildLogMessage(
+    const TLoggingContext& loggingContext,
+    const TLogger& logger,
+    TSharedRef&& message)
+{
+    if (HasMessageTags(loggingContext, logger)) {
+        TMessageStringBuilder builder;
+        AppendLogMessage(&builder, loggingContext, logger, message);
+        return {builder.Flush(), TStringBuf()};
+    } else {
+        return {std::move(message), TStringBuf()};
+    }
+}
+
+inline TLogEvent CreateLogEvent(
+    const TLoggingContext& loggingContext,
+    const TLogger& logger,
+    ELogLevel level)
+{
+    TLogEvent event;
+    event.Instant = loggingContext.Instant;
+    event.Category = logger.GetCategory();
+    event.Essential = logger.IsEssential();
+    event.Level = level;
+    event.ThreadId = loggingContext.ThreadId;
+    event.ThreadName = loggingContext.ThreadName;
+    event.FiberId = loggingContext.FiberId;
+    event.TraceId = loggingContext.TraceId;
+    event.RequestId = loggingContext.RequestId;
+    return event;
+}
+
+inline void LogEventImpl(
+    const TLoggingContext& loggingContext,
+    const TLogger& logger,
+    ELogLevel level,
+    ::TSourceLocation sourceLocation,
+    TSharedRef message)
+{
+    auto event = CreateLogEvent(loggingContext, logger, level);
+    event.MessageKind = ELogMessageKind::Unstructured;
+    event.MessageRef = std::move(message);
+    event.Family = ELogFamily::PlainText;
+    event.SourceFile = sourceLocation.File;
+    event.SourceLine = sourceLocation.Line;
+    logger.Write(std::move(event));
+}
+
+} // namespace NDetail
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT::NLogging
diff --git a/library/cpp/yt/logging/logger.cpp b/library/cpp/yt/logging/logger.cpp
new file mode 100644
index 00000000000..7f6f217d860
--- /dev/null
+++ b/library/cpp/yt/logging/logger.cpp
@@ -0,0 +1,249 @@
+#include "logger.h"
+
+#include <library/cpp/yt/assert/assert.h>
+
+#include <library/cpp/yt/cpu_clock/clock.h>
+
+#include <util/system/compiler.h>
+#include <util/system/thread.h>
+
+namespace NYT::NLogging {
+
+////////////////////////////////////////////////////////////////////////////////
+
+namespace NDetail {
+
+TSharedRef TMessageStringBuilder::Flush()
+{
+    return Buffer_.Slice(0, GetLength());
+}
+
+void TMessageStringBuilder::DisablePerThreadCache()
+{
+    Cache_ = nullptr;
+    CacheDestroyed_ = true;
+}
+
+void TMessageStringBuilder::DoReset()
+{
+    Buffer_.Reset();
+}
+
+void TMessageStringBuilder::DoReserve(size_t newCapacity)
+{
+    auto oldLength = GetLength();
+    newCapacity = FastClp2(newCapacity);
+
+    auto newChunkSize = std::max(ChunkSize, newCapacity);
+    // Hold the old buffer until the data is copied.
+    auto oldBuffer = std::move(Buffer_);
+    auto* cache = GetCache();
+    if (Y_LIKELY(cache)) {
+        auto oldCapacity = End_ - Begin_;
+        auto deltaCapacity = newCapacity - oldCapacity;
+        if (End_ == cache->Chunk.Begin() + cache->ChunkOffset &&
+            cache->ChunkOffset + deltaCapacity <= cache->Chunk.Size())
+        {
+            // Resize inplace.
+            Buffer_ = cache->Chunk.Slice(cache->ChunkOffset - oldCapacity, cache->ChunkOffset + deltaCapacity);
+            cache->ChunkOffset += deltaCapacity;
+            End_ = Begin_ + newCapacity;
+            return;
+        }
+
+        if (Y_UNLIKELY(cache->ChunkOffset + newCapacity > cache->Chunk.Size())) {
+            cache->Chunk = TSharedMutableRef::Allocate<TMessageBufferTag>(newChunkSize, {.InitializeStorage = false});
+            cache->ChunkOffset = 0;
+        }
+
+        Buffer_ = cache->Chunk.Slice(cache->ChunkOffset, cache->ChunkOffset + newCapacity);
+        cache->ChunkOffset += newCapacity;
+    } else {
+        Buffer_ = TSharedMutableRef::Allocate<TMessageBufferTag>(newChunkSize, {.InitializeStorage = false});
+        newCapacity = newChunkSize;
+    }
+    if (oldLength > 0) {
+        ::memcpy(Buffer_.Begin(), Begin_, oldLength);
+    }
+    Begin_ = Buffer_.Begin();
+    End_ = Begin_ + newCapacity;
+}
+
+TMessageStringBuilder::TPerThreadCache* TMessageStringBuilder::GetCache()
+{
+    if (Y_LIKELY(Cache_)) {
+        return Cache_;
+    }
+    if (CacheDestroyed_) {
+        return nullptr;
+    }
+    static thread_local TPerThreadCache Cache;
+    Cache_ = &Cache;
+    return Cache_;
+}
+
+TMessageStringBuilder::TPerThreadCache::~TPerThreadCache()
+{
+    TMessageStringBuilder::DisablePerThreadCache();
+}
+
+thread_local TMessageStringBuilder::TPerThreadCache* TMessageStringBuilder::Cache_;
+thread_local bool TMessageStringBuilder::CacheDestroyed_;
+
+} // namespace NDetail
+
+////////////////////////////////////////////////////////////////////////////////
+
+Y_WEAK TLoggingContext GetLoggingContext()
+{
+    return {
+        .Instant = GetCpuInstant(),
+        .ThreadId = TThread::CurrentThreadId(),
+        .ThreadName = GetLoggingThreadName(),
+    };
+}
+
+Y_WEAK ILogManager* GetDefaultLogManager()
+{
+    return nullptr;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+TLoggingThreadName GetLoggingThreadName()
+{
+    static thread_local TLoggingThreadName loggingThreadName;
+    if (loggingThreadName.Length == 0) {
+        if (auto name = TThread::CurrentThreadName()) {
+            auto length = std::min(TLoggingThreadName::BufferCapacity - 1, static_cast<int>(name.length()));
+            loggingThreadName.Length = length;
+            ::memcpy(loggingThreadName.Buffer.data(), name.data(), length);
+        }
+    }
+    return loggingThreadName;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+TLogger::TLogger(ILogManager* logManager, TStringBuf categoryName)
+    : LogManager_(logManager)
+    , Category_(LogManager_ ? LogManager_->GetCategory(categoryName) : nullptr)
+    , MinLevel_(LogManager_ ? LoggerDefaultMinLevel : NullLoggerMinLevel)
+{ }
+
+TLogger::TLogger(TStringBuf categoryName)
+    : TLogger(GetDefaultLogManager(), categoryName)
+{ }
+
+TLogger::operator bool() const
+{
+    return LogManager_;
+}
+
+const TLoggingCategory* TLogger::GetCategory() const
+{
+    return Category_;
+}
+
+bool TLogger::IsLevelEnabledHeavy(ELogLevel level) const
+{
+    // Note that we managed to reach this point, i.e. level >= MinLevel_,
+    // which implies that MinLevel_ != ELogLevel::Maximum, so this logger was not
+    // default constructed, thus it has non-trivial category.
+    YT_ASSERT(Category_);
+
+    if (Category_->CurrentVersion != Category_->ActualVersion->load(std::memory_order::relaxed)) {
+        LogManager_->UpdateCategory(const_cast<TLoggingCategory*>(Category_));
+    }
+
+    return level >= Category_->MinPlainTextLevel;
+}
+
+bool TLogger::GetAbortOnAlert() const
+{
+    return LogManager_->GetAbortOnAlert();
+}
+
+bool TLogger::IsEssential() const
+{
+    return Essential_;
+}
+
+void TLogger::UpdateAnchor(TLoggingAnchor* anchor) const
+{
+    LogManager_->UpdateAnchor(anchor);
+}
+
+void TLogger::RegisterStaticAnchor(TLoggingAnchor* anchor, ::TSourceLocation sourceLocation, TStringBuf message) const
+{
+    LogManager_->RegisterStaticAnchor(anchor, sourceLocation, message);
+}
+
+void TLogger::Write(TLogEvent&& event) const
+{
+    LogManager_->Enqueue(std::move(event));
+}
+
+void TLogger::AddRawTag(const TString& tag)
+{
+    if (!Tag_.empty()) {
+        Tag_ += ", ";
+    }
+    Tag_ += tag;
+}
+
+TLogger TLogger::WithRawTag(const TString& tag) const
+{
+    auto result = *this;
+    result.AddRawTag(tag);
+    return result;
+}
+
+TLogger TLogger::WithEssential(bool essential) const
+{
+    auto result = *this;
+    result.Essential_ = essential;
+    return result;
+}
+
+TLogger TLogger::WithMinLevel(ELogLevel minLevel) const
+{
+    auto result = *this;
+    if (result) {
+        result.MinLevel_ = minLevel;
+    }
+    return result;
+}
+
+const TString& TLogger::GetTag() const
+{
+    return Tag_;
+}
+
+const TLogger::TStructuredTags& TLogger::GetStructuredTags() const
+{
+    return StructuredTags_;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+void LogStructuredEvent(
+    const TLogger& logger,
+    NYson::TYsonString message,
+    ELogLevel level)
+{
+    YT_VERIFY(message.GetType() == NYson::EYsonType::MapFragment);
+    auto loggingContext = GetLoggingContext();
+    auto event = NDetail::CreateLogEvent(
+        loggingContext,
+        logger,
+        level);
+    event.MessageKind = ELogMessageKind::Structured;
+    event.MessageRef = message.ToSharedRef();
+    event.Family = ELogFamily::Structured;
+    logger.Write(std::move(event));
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT::NLogging
diff --git a/library/cpp/yt/logging/logger.h b/library/cpp/yt/logging/logger.h
new file mode 100644
index 00000000000..26b415a6b66
--- /dev/null
+++ b/library/cpp/yt/logging/logger.h
@@ -0,0 +1,345 @@
+#pragma once
+
+#include "public.h"
+
+#include <library/cpp/yt/string/format.h>
+
+#include <library/cpp/yt/memory/ref.h>
+
+#include <library/cpp/yt/cpu_clock/public.h>
+
+#include <library/cpp/yt/yson_string/string.h>
+
+#include <library/cpp/yt/misc/guid.h>
+
+#include <library/cpp/yt/memory/leaky_singleton.h>
+
+#include <util/system/src_location.h>
+
+#include <util/generic/size_literals.h>
+
+#include <atomic>
+
+namespace NYT::NLogging {
+
+////////////////////////////////////////////////////////////////////////////////
+
+struct TLoggingCategory
+{
+    TString Name;
+    //! This value is used for early dropping of plaintext events in order
+    //! to reduce load on logging thread for events which are definitely going
+    //! to be dropped due to rule setup.
+    //! NB: this optimization is used only for plaintext events since structured
+    //! logging rate is negligible comparing to the plaintext logging rate.
+    std::atomic<ELogLevel> MinPlainTextLevel;
+    std::atomic<int> CurrentVersion;
+    std::atomic<int>* ActualVersion;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+
+struct TLoggingAnchor
+{
+    std::atomic<bool> Registered = false;
+    ::TSourceLocation SourceLocation = {TStringBuf{}, 0};
+    TString AnchorMessage;
+    TLoggingAnchor* NextAnchor = nullptr;
+
+    std::atomic<int> CurrentVersion = 0;
+    std::atomic<bool> Enabled = false;
+
+    struct TCounter
+    {
+        std::atomic<i64> Current = 0;
+        i64 Previous = 0;
+    };
+
+    TCounter MessageCounter;
+    TCounter ByteCounter;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+
+struct TLoggingThreadName
+{
+    static constexpr int BufferCapacity = 16; // including zero terminator
+    std::array<char, BufferCapacity> Buffer; // zero-terminated
+    int Length; // not including zero terminator
+};
+
+TLoggingThreadName GetLoggingThreadName();
+
+////////////////////////////////////////////////////////////////////////////////
+// Declare some type aliases to avoid circular dependencies.
+using TThreadId = size_t;
+using TFiberId = size_t;
+using TTraceId = TGuid;
+using TRequestId = TGuid;
+
+////////////////////////////////////////////////////////////////////////////////
+
+DEFINE_ENUM(ELogMessageKind,
+    (Unstructured)
+    (Structured)
+);
+
+struct TLogEvent
+{
+    const TLoggingCategory* Category = nullptr;
+    ELogLevel Level = ELogLevel::Minimum;
+    ELogFamily Family = ELogFamily::PlainText;
+    bool Essential = false;
+
+    ELogMessageKind MessageKind = ELogMessageKind::Unstructured;
+    TSharedRef MessageRef;
+
+    TCpuInstant Instant = 0;
+
+    TThreadId ThreadId = {};
+    TLoggingThreadName ThreadName = {};
+
+    TFiberId FiberId = {};
+
+    TTraceId TraceId;
+    TRequestId RequestId;
+
+    TStringBuf SourceFile;
+    int SourceLine = -1;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+
+struct ILogManager
+{
+    virtual ~ILogManager() = default;
+
+    virtual void RegisterStaticAnchor(
+        TLoggingAnchor* position,
+        ::TSourceLocation sourceLocation,
+        TStringBuf anchorMessage) = 0;
+    virtual void UpdateAnchor(TLoggingAnchor* position) = 0;
+
+    virtual void Enqueue(TLogEvent&& event) = 0;
+
+    virtual const TLoggingCategory* GetCategory(TStringBuf categoryName) = 0;
+    virtual void UpdateCategory(TLoggingCategory* category) = 0;
+
+    virtual bool GetAbortOnAlert() const = 0;
+};
+
+ILogManager* GetDefaultLogManager();
+
+////////////////////////////////////////////////////////////////////////////////
+
+struct TLoggingContext
+{
+    TCpuInstant Instant;
+    TThreadId ThreadId;
+    TLoggingThreadName ThreadName;
+    TFiberId FiberId;
+    TTraceId TraceId;
+    TRequestId RequestId;
+    TStringBuf TraceLoggingTag;
+};
+
+TLoggingContext GetLoggingContext();
+
+////////////////////////////////////////////////////////////////////////////////
+
+static constexpr auto NullLoggerMinLevel = ELogLevel::Maximum;
+
+// Min level for non-null logger depends on whether we are in debug or release build.
+// - For release mode default behavior is to omit trace logging,
+//   this is done by setting logger min level to Debug by default.
+// - For debug mode logger min level is set to trace by default, so that trace logging is
+//   allowed by logger, but still may be discarded by category min level.
+#ifdef NDEBUG
+static constexpr auto LoggerDefaultMinLevel = ELogLevel::Debug;
+#else
+static constexpr auto LoggerDefaultMinLevel = ELogLevel::Trace;
+#endif
+
+class TLogger
+{
+public:
+    using TStructuredTag = std::pair<TString, NYson::TYsonString>;
+    // TODO(max42): switch to TCompactVector after YT-15430.
+    using TStructuredTags = std::vector<TStructuredTag>;
+
+    TLogger() = default;
+    TLogger(const TLogger& other) = default;
+    TLogger& operator=(const TLogger& other) = default;
+
+    TLogger(ILogManager* logManager, TStringBuf categoryName);
+    explicit TLogger(TStringBuf categoryName);
+
+    explicit operator bool() const;
+
+    const TLoggingCategory* GetCategory() const;
+
+    //! Validate that level is admitted by logger's own min level
+    //! and by category's min level.
+    bool IsLevelEnabled(ELogLevel level) const;
+
+    bool GetAbortOnAlert() const;
+
+    bool IsEssential() const;
+
+    bool IsAnchorUpToDate(const TLoggingAnchor& anchor) const;
+    void UpdateAnchor(TLoggingAnchor* anchor) const;
+    void RegisterStaticAnchor(TLoggingAnchor* anchor, ::TSourceLocation sourceLocation, TStringBuf message) const;
+
+    void Write(TLogEvent&& event) const;
+
+    void AddRawTag(const TString& tag);
+    template <class... TArgs>
+    void AddTag(const char* format, TArgs&&... args);
+
+    template <class TType>
+    void AddStructuredTag(TStringBuf key, TType value);
+
+    TLogger WithRawTag(const TString& tag) const;
+    template <class... TArgs>
+    TLogger WithTag(const char* format, TArgs&&... args) const;
+
+    template <class TType>
+    TLogger WithStructuredTag(TStringBuf key, TType value) const;
+
+    TLogger WithMinLevel(ELogLevel minLevel) const;
+
+    TLogger WithEssential(bool essential = true) const;
+
+    const TString& GetTag() const;
+    const TStructuredTags& GetStructuredTags() const;
+
+protected:
+    // These fields are set only during logger creation, so they are effectively const
+    // and accessing them is thread-safe.
+    ILogManager* LogManager_ = nullptr;
+    const TLoggingCategory* Category_ = nullptr;
+    bool Essential_ = false;
+    ELogLevel MinLevel_ = NullLoggerMinLevel;
+    TString Tag_;
+    TStructuredTags StructuredTags_;
+
+private:
+    //! This method checks level against category's min level.
+    //! Refer to comment in TLogger::IsLevelEnabled for more details.
+    bool IsLevelEnabledHeavy(ELogLevel level) const;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+
+void LogStructuredEvent(
+    const TLogger& logger,
+    NYson::TYsonString message,
+    ELogLevel level);
+
+////////////////////////////////////////////////////////////////////////////////
+
+#ifdef YT_ENABLE_TRACE_LOGGING
+#define YT_LOG_TRACE(...)                      YT_LOG_EVENT(Logger, ::NYT::NLogging::ELogLevel::Trace, __VA_ARGS__)
+#define YT_LOG_TRACE_IF(condition, ...)        if (condition)    YT_LOG_TRACE(__VA_ARGS__)
+#define YT_LOG_TRACE_UNLESS(condition, ...)    if (!(condition)) YT_LOG_TRACE(__VA_ARGS__)
+#else
+#define YT_LOG_UNUSED(...)                     if (true) { } else { YT_LOG_DEBUG(__VA_ARGS__); }
+#define YT_LOG_TRACE(...)                      YT_LOG_UNUSED(__VA_ARGS__)
+#define YT_LOG_TRACE_IF(condition, ...)        YT_LOG_UNUSED(__VA_ARGS__)
+#define YT_LOG_TRACE_UNLESS(condition, ...)    YT_LOG_UNUSED(__VA_ARGS__)
+#endif
+
+#define YT_LOG_DEBUG(...)                      YT_LOG_EVENT(Logger, ::NYT::NLogging::ELogLevel::Debug, __VA_ARGS__)
+#define YT_LOG_DEBUG_IF(condition, ...)        if (condition)    YT_LOG_DEBUG(__VA_ARGS__)
+#define YT_LOG_DEBUG_UNLESS(condition, ...)    if (!(condition)) YT_LOG_DEBUG(__VA_ARGS__)
+
+#define YT_LOG_INFO(...)                       YT_LOG_EVENT(Logger, ::NYT::NLogging::ELogLevel::Info, __VA_ARGS__)
+#define YT_LOG_INFO_IF(condition, ...)         if (condition)    YT_LOG_INFO(__VA_ARGS__)
+#define YT_LOG_INFO_UNLESS(condition, ...)     if (!(condition)) YT_LOG_INFO(__VA_ARGS__)
+
+#define YT_LOG_WARNING(...)                    YT_LOG_EVENT(Logger, ::NYT::NLogging::ELogLevel::Warning, __VA_ARGS__)
+#define YT_LOG_WARNING_IF(condition, ...)      if (condition)    YT_LOG_WARNING(__VA_ARGS__)
+#define YT_LOG_WARNING_UNLESS(condition, ...)  if (!(condition)) YT_LOG_WARNING(__VA_ARGS__)
+
+#define YT_LOG_ERROR(...)                      YT_LOG_EVENT(Logger, ::NYT::NLogging::ELogLevel::Error, __VA_ARGS__)
+#define YT_LOG_ERROR_IF(condition, ...)        if (condition)    YT_LOG_ERROR(__VA_ARGS__)
+#define YT_LOG_ERROR_UNLESS(condition, ...)    if (!(condition)) YT_LOG_ERROR(__VA_ARGS__)
+
+#define YT_LOG_ALERT(...) \
+    do { \
+        YT_LOG_EVENT(Logger, ::NYT::NLogging::ELogLevel::Alert, __VA_ARGS__); \
+        YT_VERIFY(!Logger.GetAbortOnAlert()); \
+    } while(false)
+#define YT_LOG_ALERT_IF(condition, ...)        if (condition)    YT_LOG_ALERT(__VA_ARGS__)
+#define YT_LOG_ALERT_UNLESS(condition, ...)    if (!(condition)) YT_LOG_ALERT(__VA_ARGS__)
+
+#define YT_LOG_FATAL(...) \
+    do { \
+        YT_LOG_EVENT(Logger, ::NYT::NLogging::ELogLevel::Fatal, __VA_ARGS__); \
+        YT_ABORT(); \
+    } while(false)
+#define YT_LOG_FATAL_IF(condition, ...)        if (Y_UNLIKELY(condition)) YT_LOG_FATAL(__VA_ARGS__)
+#define YT_LOG_FATAL_UNLESS(condition, ...)    if (!Y_LIKELY(condition)) YT_LOG_FATAL(__VA_ARGS__)
+
+#define YT_LOG_EVENT(logger, level, ...) \
+    YT_LOG_EVENT_WITH_ANCHOR(logger, level, nullptr, __VA_ARGS__)
+
+#define YT_LOG_EVENT_WITH_ANCHOR(logger, level, anchor, ...) \
+    do { \
+        const auto& logger__##__LINE__ = (logger); \
+        auto level__##__LINE__ = (level); \
+        \
+        if (!logger__##__LINE__.IsLevelEnabled(level__##__LINE__)) { \
+            break; \
+        } \
+        \
+        auto location__##__LINE__ = __LOCATION__; \
+        \
+        ::NYT::NLogging::TLoggingAnchor* anchor__##__LINE__ = (anchor); \
+        if (!anchor__##__LINE__) { \
+            static ::NYT::TLeakyStorage<::NYT::NLogging::TLoggingAnchor> staticAnchor__##__LINE__; \
+            anchor__##__LINE__ = staticAnchor__##__LINE__.Get(); \
+        } \
+        \
+        bool anchorUpToDate__##__LINE__ = logger__##__LINE__.IsAnchorUpToDate(*anchor__##__LINE__); \
+        if (anchorUpToDate__##__LINE__ && !anchor__##__LINE__->Enabled.load(std::memory_order::relaxed)) { \
+            break; \
+        } \
+        \
+        auto loggingContext__##__LINE__ = ::NYT::NLogging::GetLoggingContext(); \
+        auto message__##__LINE__ = ::NYT::NLogging::NDetail::BuildLogMessage(loggingContext__##__LINE__, logger__##__LINE__, __VA_ARGS__); \
+        \
+        if (!anchorUpToDate__##__LINE__) { \
+            logger__##__LINE__.RegisterStaticAnchor(anchor__##__LINE__, location__##__LINE__, message__##__LINE__.Anchor); \
+            logger__##__LINE__.UpdateAnchor(anchor__##__LINE__); \
+        } \
+        \
+        if (!anchor__##__LINE__->Enabled.load(std::memory_order::relaxed)) { \
+            break; \
+        } \
+        \
+        static thread_local i64 localByteCounter__##__LINE__; \
+        static thread_local ui8 localMessageCounter__##__LINE__; \
+        \
+        localByteCounter__##__LINE__ += message__##__LINE__.MessageRef.Size(); \
+        if (Y_UNLIKELY(++localMessageCounter__##__LINE__ == 0)) { \
+            anchor__##__LINE__->MessageCounter.Current += 256; \
+            anchor__##__LINE__->ByteCounter.Current += localByteCounter__##__LINE__; \
+            localByteCounter__##__LINE__ = 0; \
+        } \
+        \
+        ::NYT::NLogging::NDetail::LogEventImpl( \
+            loggingContext__##__LINE__, \
+            logger__##__LINE__, \
+            level__##__LINE__, \
+            location__##__LINE__, \
+            std::move(message__##__LINE__.MessageRef)); \
+    } while (false)
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT::NLogging
+
+#define LOGGER_INL_H_
+#include "logger-inl.h"
+#undef LOGGER_INL_H_
diff --git a/library/cpp/yt/logging/public.h b/library/cpp/yt/logging/public.h
new file mode 100644
index 00000000000..1e2b59ca0d3
--- /dev/null
+++ b/library/cpp/yt/logging/public.h
@@ -0,0 +1,39 @@
+#pragma once
+
+#include <library/cpp/yt/misc/enum.h>
+
+namespace NYT::NLogging {
+
+////////////////////////////////////////////////////////////////////////////////
+
+// Any change to this enum must be also propagated to FormatLevel.
+DEFINE_ENUM(ELogLevel,
+    (Minimum)
+    (Trace)
+    (Debug)
+    (Info)
+    (Warning)
+    (Error)
+    (Alert)
+    (Fatal)
+    (Maximum)
+);
+
+DEFINE_ENUM(ELogFamily,
+    (PlainText)
+    (Structured)
+);
+
+////////////////////////////////////////////////////////////////////////////////
+
+struct TLoggingCategory;
+struct TLoggingAnchor;
+struct TLogEvent;
+struct TLoggingContext;
+
+class TLogger;
+struct ILogManager;
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT::NLogging
diff --git a/library/cpp/yt/logging/unittests/logger_ut.cpp b/library/cpp/yt/logging/unittests/logger_ut.cpp
new file mode 100644
index 00000000000..7696ea4a83b
--- /dev/null
+++ b/library/cpp/yt/logging/unittests/logger_ut.cpp
@@ -0,0 +1,38 @@
+#include <library/cpp/testing/gtest/gtest.h>
+
+#include <library/cpp/yt/logging/logger.h>
+
+namespace NYT::NLogging {
+namespace {
+
+////////////////////////////////////////////////////////////////////////////////
+
+TEST(TLogger, NullByDefault)
+{
+    {
+        TLogger logger;
+        EXPECT_FALSE(logger);
+        EXPECT_FALSE(logger.IsLevelEnabled(ELogLevel::Fatal));
+    }
+    {
+        TLogger logger{"Category"};
+        EXPECT_FALSE(logger);
+        EXPECT_FALSE(logger.IsLevelEnabled(ELogLevel::Fatal));
+    }
+}
+
+TEST(TLogger, CopyOfNullLogger)
+{
+    TLogger nullLogger{/*logManager*/ nullptr, "Category"};
+    ASSERT_FALSE(nullLogger);
+
+    auto logger = nullLogger.WithMinLevel(ELogLevel::Debug);
+
+    EXPECT_FALSE(logger);
+    EXPECT_FALSE(logger.IsLevelEnabled(ELogLevel::Fatal));
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace
+} // namespace NYT::NLogging
diff --git a/library/cpp/yt/memory/leaky_ref_counted_singleton-inl.h b/library/cpp/yt/memory/leaky_ref_counted_singleton-inl.h
new file mode 100644
index 00000000000..1fba63c427a
--- /dev/null
+++ b/library/cpp/yt/memory/leaky_ref_counted_singleton-inl.h
@@ -0,0 +1,43 @@
+#ifndef LEAKY_REF_COUNTED_SINGLETON_INL_H_
+#error "Direct inclusion of this file is not allowed, include leaky_ref_counted_singleton.h"
+// For the sake of sane code completion.
+#include "leaky_ref_counted_singleton.h"
+#endif
+
+#include "new.h"
+
+#include <atomic>
+#include <mutex>
+
+#include <util/system/compiler.h>
+#include <util/system/sanitizers.h>
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+template <class T, class... TArgs>
+TIntrusivePtr<T> LeakyRefCountedSingleton(TArgs&&... args)
+{
+    static std::atomic<T*> Ptr;
+    auto* ptr = Ptr.load(std::memory_order::acquire);
+    if (Y_LIKELY(ptr)) {
+        return ptr;
+    }
+
+    static std::once_flag Initialized;
+    std::call_once(Initialized, [&] {
+        auto ptr = New<T>(std::forward<TArgs>(args)...);
+        Ref(ptr.Get());
+        Ptr.store(ptr.Get());
+#if defined(_asan_enabled_)
+        NSan::MarkAsIntentionallyLeaked(ptr.Get());
+#endif
+    });
+
+    return Ptr.load();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
diff --git a/library/cpp/yt/memory/leaky_ref_counted_singleton.h b/library/cpp/yt/memory/leaky_ref_counted_singleton.h
new file mode 100644
index 00000000000..4ad5b5f0528
--- /dev/null
+++ b/library/cpp/yt/memory/leaky_ref_counted_singleton.h
@@ -0,0 +1,18 @@
+#pragma once
+
+#include "intrusive_ptr.h"
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+template <class T, class... TArgs>
+TIntrusivePtr<T> LeakyRefCountedSingleton(TArgs&&... args);
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
+
+#define LEAKY_REF_COUNTED_SINGLETON_INL_H_
+#include "leaky_ref_counted_singleton-inl.h"
+#undef LEAKY_REF_COUNTED_SINGLETON_INL_H_
diff --git a/library/cpp/yt/misc/property.h b/library/cpp/yt/misc/property.h
new file mode 100644
index 00000000000..bef8024ae15
--- /dev/null
+++ b/library/cpp/yt/misc/property.h
@@ -0,0 +1,289 @@
+#pragma once
+
+////////////////////////////////////////////////////////////////////////////////
+
+//! Declares a trivial public read-write property that is passed by reference.
+#define DECLARE_BYREF_RW_PROPERTY(type, name) \
+public: \
+    type& name(); \
+    const type& name() const;
+
+//! Defines a trivial public read-write property that is passed by reference.
+//! All arguments after name are used as default value (via braced-init-list).
+#define DEFINE_BYREF_RW_PROPERTY(type, name, ...) \
+protected: \
+    type name##_ { __VA_ARGS__ }; \
+    \
+public: \
+    Y_FORCE_INLINE type& name() \
+    { \
+        return name##_; \
+    } \
+    \
+    Y_FORCE_INLINE const type& name() const \
+    { \
+        return name##_; \
+    }
+
+//! Defines a trivial public read-write property that is passed by reference
+//! and is not inline-initialized.
+#define DEFINE_BYREF_RW_PROPERTY_NO_INIT(type, name) \
+protected: \
+    type name##_; \
+    \
+public: \
+    Y_FORCE_INLINE type& name() \
+    { \
+        return name##_; \
+    } \
+    \
+    Y_FORCE_INLINE const type& name() const \
+    { \
+        return name##_; \
+    }
+
+//! Forwards a trivial public read-write property that is passed by reference.
+#define DELEGATE_BYREF_RW_PROPERTY(declaringType, type, name, delegateTo) \
+    type& declaringType::name() \
+    { \
+        return (delegateTo).name(); \
+    } \
+    \
+    const type& declaringType::name() const \
+    { \
+        return (delegateTo).name(); \
+    }
+
+////////////////////////////////////////////////////////////////////////////////
+
+//! Declares a trivial public read-only property that is passed by reference.
+#define DECLARE_BYREF_RO_PROPERTY(type, name) \
+public: \
+    const type& name() const;
+
+//! Defines a trivial public read-only property that is passed by reference.
+//! All arguments after name are used as default value (via braced-init-list).
+#define DEFINE_BYREF_RO_PROPERTY(type, name, ...) \
+protected: \
+    type name##_ { __VA_ARGS__ }; \
+    \
+public: \
+    Y_FORCE_INLINE const type& name() const \
+    { \
+        return name##_; \
+    }
+
+//! Defines a trivial public read-only property that is passed by reference
+//! and is not inline-initialized.
+#define DEFINE_BYREF_RO_PROPERTY_NO_INIT(type, name) \
+protected: \
+    type name##_; \
+    \
+public: \
+    Y_FORCE_INLINE const type& name() const \
+    { \
+        return name##_; \
+    }
+
+//! Forwards a trivial public read-only property that is passed by reference.
+#define DELEGATE_BYREF_RO_PROPERTY(declaringType, type, name, delegateTo) \
+    const type& declaringType::name() const \
+    { \
+        return (delegateTo).name(); \
+    }
+
+////////////////////////////////////////////////////////////////////////////////
+
+//! Declares a trivial public read-write property that is passed by value.
+#define DECLARE_BYVAL_RW_PROPERTY(type, name) \
+public: \
+    type Get##name() const; \
+    void Set##name(type value);
+
+//! Defines a trivial public read-write property that is passed by value.
+//! All arguments after name are used as default value (via braced-init-list).
+#define DEFINE_BYVAL_RW_PROPERTY(type, name, ...) \
+protected: \
+    type name##_ { __VA_ARGS__ }; \
+    \
+public: \
+    Y_FORCE_INLINE type Get##name() const \
+    { \
+        return name##_; \
+    } \
+    \
+    Y_FORCE_INLINE void Set##name(type value) \
+    { \
+        name##_ = value; \
+    } \
+
+//! Defines a trivial public read-write property that is passed by value.
+//! All arguments after name are used as default value (via braced-init-list).
+#define DEFINE_BYVAL_RW_PROPERTY_WITH_FLUENT_SETTER(declaringType, type, name, ...) \
+protected: \
+    type name##_ { __VA_ARGS__ }; \
+    \
+public: \
+    Y_FORCE_INLINE type Get##name() const \
+    { \
+        return name##_; \
+    } \
+    \
+    Y_FORCE_INLINE void Set##name(type value) &\
+    { \
+        name##_ = value; \
+    } \
+    \
+    Y_FORCE_INLINE declaringType&& Set##name(type value) &&\
+    { \
+        name##_ = value; \
+        return std::move(*this); \
+    } \
+
+//! Defines a trivial public read-write property that is passed by value
+//! and is not inline-initialized.
+#define DEFINE_BYVAL_RW_PROPERTY_NO_INIT(type, name, ...) \
+protected: \
+    type name##_; \
+    \
+public: \
+    Y_FORCE_INLINE type Get##name() const \
+    { \
+        return name##_; \
+    } \
+    \
+    Y_FORCE_INLINE void Set##name(type value) \
+    { \
+        name##_ = value; \
+    } \
+
+//! Forwards a trivial public read-write property that is passed by value.
+#define DELEGATE_BYVAL_RW_PROPERTY(declaringType, type, name, delegateTo) \
+    type declaringType::Get##name() const \
+    { \
+        return (delegateTo).Get##name(); \
+    } \
+    \
+    void declaringType::Set##name(type value) \
+    { \
+        (delegateTo).Set##name(value); \
+    }
+
+////////////////////////////////////////////////////////////////////////////////
+
+//! Declares a trivial public read-only property that is passed by value.
+#define DECLARE_BYVAL_RO_PROPERTY(type, name) \
+public: \
+    type Get##name() const;
+
+//! Defines a trivial public read-only property that is passed by value.
+//! All arguments after name are used as default value (via braced-init-list).
+#define DEFINE_BYVAL_RO_PROPERTY(type, name, ...) \
+protected: \
+    type name##_ { __VA_ARGS__ }; \
+    \
+public: \
+    Y_FORCE_INLINE type Get##name() const \
+    { \
+        return name##_; \
+    }
+
+
+//! Defines a trivial public read-only property that is passed by value
+//! and is not inline-initialized.
+#define DEFINE_BYVAL_RO_PROPERTY_NO_INIT(type, name) \
+protected: \
+    type name##_; \
+    \
+public: \
+    Y_FORCE_INLINE type Get##name() const \
+    { \
+        return name##_; \
+    }
+
+//! Forwards a trivial public read-only property that is passed by value.
+#define DELEGATE_BYVAL_RO_PROPERTY(declaringType, type, name, delegateTo) \
+    type declaringType::Get##name() \
+    { \
+        return (delegateTo).Get##name(); \
+    }
+
+////////////////////////////////////////////////////////////////////////////////
+
+//! Below are macro helpers for extra properties.
+//! Extra properties should be used for lazy memory allocation for properties that
+//! hold default values for the majority of objects.
+
+//! Initializes extra property holder if it is not initialized.
+#define INITIALIZE_EXTRA_PROPERTY_HOLDER(holder) \
+    if (!holder##_) { \
+        holder##_.reset(new decltype(holder##_)::element_type()); \
+    }
+
+//! Declares an extra property holder. Holder contains extra properties values.
+//! Holder is not created until some property is set with a non-default value.
+//! If there is no holder property getter returns default value.
+#define DECLARE_EXTRA_PROPERTY_HOLDER(type, holder) \
+public: \
+    Y_FORCE_INLINE bool HasCustom##holder() const \
+    { \
+        return static_cast<bool>(holder##_); \
+    } \
+    Y_FORCE_INLINE const type* GetCustom##holder() const \
+    { \
+        return holder##_.get(); \
+    } \
+    Y_FORCE_INLINE type* GetCustom##holder() \
+    { \
+        return holder##_.get(); \
+    } \
+    Y_FORCE_INLINE void InitializeCustom##holder() \
+    { \
+        INITIALIZE_EXTRA_PROPERTY_HOLDER(holder) \
+    } \
+private: \
+    std::unique_ptr<type> holder##_; \
+    static const type Default##holder##_;
+
+//! Defines a storage for extra properties default values.
+#define DEFINE_EXTRA_PROPERTY_HOLDER(class, type, holder) \
+    const type class::Default##holder##_;
+
+//! Defines a public read-write extra property that is passed by value.
+#define DEFINE_BYVAL_RW_EXTRA_PROPERTY(holder, name) \
+public: \
+    Y_FORCE_INLINE decltype(holder##_->name) Get##name() const \
+    { \
+        if (!holder##_) { \
+            return Default##holder##_.name; \
+        } \
+        return holder##_->name; \
+    } \
+    Y_FORCE_INLINE void Set##name(decltype(holder##_->name) val) \
+    { \
+        if (!holder##_) { \
+            if (val == Default##holder##_.name) { \
+                return; \
+            } \
+            INITIALIZE_EXTRA_PROPERTY_HOLDER(holder); \
+        } \
+        holder##_->name = val; \
+    }
+
+//! Defines a public read-write extra property that is passed by reference.
+#define DEFINE_BYREF_RW_EXTRA_PROPERTY(holder, name) \
+public: \
+    Y_FORCE_INLINE const decltype(holder##_->name)& name() const \
+    { \
+        if (!holder##_) { \
+            return Default##holder##_.name; \
+        } \
+        return holder##_->name; \
+    } \
+    Y_FORCE_INLINE decltype(holder##_->name)& Mutable##name() \
+    { \
+        INITIALIZE_EXTRA_PROPERTY_HOLDER(holder); \
+        return holder##_->name; \
+    }
+
+////////////////////////////////////////////////////////////////////////////////
diff --git a/library/cpp/yt/mlock/README.md b/library/cpp/yt/mlock/README.md
new file mode 100644
index 00000000000..b61b6072c4d
--- /dev/null
+++ b/library/cpp/yt/mlock/README.md
@@ -0,0 +1,11 @@
+# mlock
+
+MlockFileMappings подгружает и лочит в память все страницы исполняемого файла.
+
+В отличии от вызова mlockall, функция не лочит другие страницы процесса.
+mlockall явно выделяет физическую память под все vma. Типичный процесс сначала
+стартует и инициализирует аллокатор, а потом уже вызывает функцию для mlock страниц.
+Аллокатор при старте выделяет большие диапазоны через mmap, но реально их не использует.
+Поэтому mlockall приводит в повышенному потреблению памяти.
+
+Также, в отличии от mlockall, функция может подгрузить страницы в память сразу. 
diff --git a/library/cpp/yt/mlock/mlock.h b/library/cpp/yt/mlock/mlock.h
new file mode 100644
index 00000000000..035fc47e373
--- /dev/null
+++ b/library/cpp/yt/mlock/mlock.h
@@ -0,0 +1,11 @@
+#pragma once
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+bool MlockFileMappings(bool populate = true);
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
diff --git a/library/cpp/yt/mlock/mlock_linux.cpp b/library/cpp/yt/mlock/mlock_linux.cpp
new file mode 100644
index 00000000000..8791869f951
--- /dev/null
+++ b/library/cpp/yt/mlock/mlock_linux.cpp
@@ -0,0 +1,89 @@
+#include "mlock.h"
+
+#include <stdio.h>
+#include <sys/mman.h>
+#include <stdint.h>
+#include <inttypes.h>
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+void PopulateFile(void* ptr, size_t size)
+{
+    constexpr size_t PageSize = 4096;
+
+    auto* begin = static_cast<volatile char*>(ptr);
+    for (auto* current = begin; current < begin + size; current += PageSize) {
+        *current;
+    }
+}
+
+bool MlockFileMappings(bool populate)
+{
+    auto* file = ::fopen("/proc/self/maps", "r");
+    if (!file) {
+        return false;
+    }
+
+    // Each line of /proc/<pid>/smaps has the following format:
+    // address           perms offset  dev   inode   path
+    // E.g.
+    // 08048000-08056000 r-xp 00000000 03:0c 64593   /usr/sbin/gpm
+
+    bool failed = false;
+    while (true) {
+        char line[1024];
+        if (!fgets(line, sizeof(line), file)) {
+            break;
+        }
+
+        char addressStr[64];
+        char permsStr[64];
+        char offsetStr[64];
+        char devStr[64];
+        int inode;
+        if (sscanf(line, "%s %s %s %s %d",
+            addressStr,
+            permsStr,
+            offsetStr,
+            devStr,
+            &inode) != 5)
+        {
+            continue;
+        }
+
+        if (inode == 0) {
+            continue;
+        }
+
+        if (permsStr[0] != 'r') {
+            continue;
+        }
+
+        uintptr_t startAddress;
+        uintptr_t endAddress;
+        if (sscanf(addressStr, "%" PRIx64 "-%" PRIx64,
+                &startAddress,
+                &endAddress) != 2)
+        {
+            continue;
+        }
+
+        if (::mlock(reinterpret_cast<const void*>(startAddress), endAddress - startAddress) != 0) {
+            failed = true;
+            continue;
+        }
+
+        if (populate) {
+            PopulateFile(reinterpret_cast<void*>(startAddress), endAddress - startAddress);
+        }
+    }
+
+    ::fclose(file);
+    return !failed;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
diff --git a/library/cpp/yt/mlock/mlock_other.cpp b/library/cpp/yt/mlock/mlock_other.cpp
new file mode 100644
index 00000000000..269c5c3cb98
--- /dev/null
+++ b/library/cpp/yt/mlock/mlock_other.cpp
@@ -0,0 +1,14 @@
+#include "mlock.h"
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+bool MlockFileMappings(bool /* populate */)
+{
+    return false;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
diff --git a/library/cpp/yt/stockpile/README.md b/library/cpp/yt/stockpile/README.md
new file mode 100644
index 00000000000..6ee4cd1b1f1
--- /dev/null
+++ b/library/cpp/yt/stockpile/README.md
@@ -0,0 +1,12 @@
+# stockpile
+
+При приближении к лимиту памяти в memory cgroup, linux запускает механизм direct reclaim,
+чтобы освободить свободную память. По опыту YT, direct reclaim очень сильно замедляет работу
+всего процесса.
+
+Проблема возникает не только, когда память занята анонимными страницами. 50% памяти контейнера
+может быть занято не dirty страницами page cache, но проблема всёравно будет проявляться. Например,
+если процесс активно читает файлы с диска без O_DIRECT, вся память очень быстро будет забита.
+
+Чтобы бороться с этой проблемой, в яндексовом ядре добавлена ручка `madvise(MADV_STOCKPILE)`.
+Больше подробностей в https://st.yandex-team.ru/KERNEL-186
\ No newline at end of file
diff --git a/library/cpp/yt/stockpile/stockpile.h b/library/cpp/yt/stockpile/stockpile.h
new file mode 100644
index 00000000000..2b1b53e9b57
--- /dev/null
+++ b/library/cpp/yt/stockpile/stockpile.h
@@ -0,0 +1,24 @@
+#pragma once
+
+#include <util/system/types.h>
+
+#include <util/generic/size_literals.h>
+
+#include <util/datetime/base.h>
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+struct TStockpileOptions
+{
+    i64 BufferSize = 4_GB;
+    int ThreadCount = 4;
+    TDuration Period = TDuration::MilliSeconds(10);
+};
+
+void StockpileMemory(const TStockpileOptions& options);
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
diff --git a/library/cpp/yt/stockpile/stockpile_linux.cpp b/library/cpp/yt/stockpile/stockpile_linux.cpp
new file mode 100644
index 00000000000..9be33e3811e
--- /dev/null
+++ b/library/cpp/yt/stockpile/stockpile_linux.cpp
@@ -0,0 +1,42 @@
+#include "stockpile.h"
+
+#include <thread>
+#include <mutex>
+
+#include <sys/mman.h>
+
+#include <util/system/thread.h>
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+namespace {
+
+void RunStockpile(const TStockpileOptions& options)
+{
+    TThread::SetCurrentThreadName("Stockpile");
+
+    constexpr int MADV_STOCKPILE = 0x59410004;
+
+    while (true) {
+        ::madvise(nullptr, options.BufferSize, MADV_STOCKPILE);
+        Sleep(options.Period);
+    }
+}
+
+} // namespace
+
+void StockpileMemory(const TStockpileOptions& options)
+{
+    static std::once_flag OnceFlag;
+    std::call_once(OnceFlag, [options] {
+        for (int i = 0; i < options.ThreadCount; i++) {
+            std::thread(RunStockpile, options).detach();
+        }
+    });
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
diff --git a/library/cpp/yt/stockpile/stockpile_other.cpp b/library/cpp/yt/stockpile/stockpile_other.cpp
new file mode 100644
index 00000000000..913ad88b206
--- /dev/null
+++ b/library/cpp/yt/stockpile/stockpile_other.cpp
@@ -0,0 +1,12 @@
+#include "stockpile.h"
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+void StockpileMemory(const TStockpileOptions& /*options*/)
+{ }
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
diff --git a/library/cpp/yt/threading/unittests/recursive_spin_lock_ut.cpp b/library/cpp/yt/threading/unittests/recursive_spin_lock_ut.cpp
new file mode 100644
index 00000000000..9c2d8f16cbf
--- /dev/null
+++ b/library/cpp/yt/threading/unittests/recursive_spin_lock_ut.cpp
@@ -0,0 +1,88 @@
+#include <library/cpp/testing/gtest/gtest.h>
+
+#include <library/cpp/yt/threading/recursive_spin_lock.h>
+#include <library/cpp/yt/threading/event_count.h>
+
+#include <thread>
+
+namespace NYT::NThreading {
+namespace {
+
+////////////////////////////////////////////////////////////////////////////////
+
+TEST(TRecursiveSpinLockTest, SingleThread)
+{
+    TRecursiveSpinLock lock;
+    EXPECT_FALSE(lock.IsLocked());
+    EXPECT_TRUE(lock.TryAcquire());
+    EXPECT_TRUE(lock.IsLocked());
+    EXPECT_TRUE(lock.TryAcquire());
+    EXPECT_TRUE(lock.IsLocked());
+    lock.Release();
+    EXPECT_TRUE(lock.IsLocked());
+    lock.Release();
+    EXPECT_FALSE(lock.IsLocked());
+    EXPECT_TRUE(lock.TryAcquire());
+    EXPECT_TRUE(lock.IsLocked());
+    lock.Release();
+    lock.Acquire();
+    lock.Release();
+}
+
+TEST(TRecursiveSpinLockTest, TwoThreads)
+{
+    TRecursiveSpinLock lock;
+    TEvent e1, e2, e3, e4, e5, e6, e7;
+
+    std::thread t1([&] {
+        e1.Wait();
+        EXPECT_TRUE(lock.IsLocked());
+        EXPECT_FALSE(lock.IsLockedByCurrentThread());
+        EXPECT_FALSE(lock.TryAcquire());
+        e2.NotifyOne();
+        e3.Wait();
+        EXPECT_TRUE(lock.IsLocked());
+        EXPECT_FALSE(lock.IsLockedByCurrentThread());
+        EXPECT_FALSE(lock.TryAcquire());
+        e4.NotifyOne();
+        e5.Wait();
+        EXPECT_FALSE(lock.IsLocked());
+        EXPECT_FALSE(lock.IsLockedByCurrentThread());
+        EXPECT_TRUE(lock.TryAcquire());
+        e6.NotifyOne();
+        e7.Wait();
+        lock.Release();
+    });
+
+    std::thread t2([&] {
+        EXPECT_FALSE(lock.IsLocked());
+        EXPECT_TRUE(lock.TryAcquire());
+        EXPECT_TRUE(lock.IsLockedByCurrentThread());
+        e1.NotifyOne();
+        e2.Wait();
+        EXPECT_TRUE(lock.TryAcquire());
+        EXPECT_TRUE(lock.IsLockedByCurrentThread());
+        e3.NotifyOne();
+        e4.Wait();
+        lock.Release();
+        lock.Release();
+        EXPECT_FALSE(lock.IsLocked());
+        e5.NotifyOne();
+        e6.Wait();
+        EXPECT_TRUE(lock.IsLocked());
+        EXPECT_FALSE(lock.IsLockedByCurrentThread());
+        e7.NotifyOne();
+        lock.Acquire();
+        lock.Acquire();
+        lock.Release();
+        lock.Release();
+    });
+
+    t1.join();
+    t2.join();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace
+} // namespace NYT::NThreading
diff --git a/library/cpp/yt/threading/unittests/spin_wait_ut.cpp b/library/cpp/yt/threading/unittests/spin_wait_ut.cpp
new file mode 100644
index 00000000000..8469634f346
--- /dev/null
+++ b/library/cpp/yt/threading/unittests/spin_wait_ut.cpp
@@ -0,0 +1,48 @@
+#include <library/cpp/testing/gtest/gtest.h>
+
+#include <library/cpp/yt/threading/spin_wait.h>
+#include <library/cpp/yt/threading/spin_wait_hook.h>
+
+#include <thread>
+#include <mutex>
+
+namespace NYT::NThreading {
+namespace {
+
+////////////////////////////////////////////////////////////////////////////////
+
+bool SpinWaitSlowPathHookInvoked;
+
+void SpinWaitSlowPathHook(
+    TCpuDuration cpuDelay,
+    const TSourceLocation& /*location*/,
+    ESpinLockActivityKind /*activityKind*/)
+{
+    SpinWaitSlowPathHookInvoked = true;
+    auto delay = CpuDurationToDuration(cpuDelay);
+    EXPECT_GE(delay, TDuration::Seconds(1));
+    EXPECT_LE(delay, TDuration::Seconds(5));
+}
+
+TEST(TSpinWaitTest, SlowPathHook)
+{
+    static std::once_flag registerFlag;
+    std::call_once(
+        registerFlag,
+        [] {
+            RegisterSpinWaitSlowPathHook(SpinWaitSlowPathHook);
+        });
+    SpinWaitSlowPathHookInvoked = false;
+    {
+        TSpinWait spinWait(__LOCATION__, ESpinLockActivityKind::ReadWrite);
+        for (int i = 0; i < 1'000'000; ++i) {
+            spinWait.Wait();
+        }
+    }
+    EXPECT_TRUE(SpinWaitSlowPathHookInvoked);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace
+} // namespace NYT::NThreading