diff --git a/folly/io/IOBuf.cpp b/folly/io/IOBuf.cpp
index 214abbaab0e..4eba7aca154 100644
--- a/folly/io/IOBuf.cpp
+++ b/folly/io/IOBuf.cpp
@@ -670,7 +670,7 @@ IOBuf& IOBuf::operator=(const IOBuf& other) {
   return *this;
 }
 
-bool IOBuf::empty() const {
+bool IOBuf::empty() const noexcept {
   const IOBuf* current = this;
   do {
     if (current->length() != 0) {
@@ -681,7 +681,7 @@ bool IOBuf::empty() const {
   return true;
 }
 
-size_t IOBuf::countChainElements() const {
+size_t IOBuf::countChainElements() const noexcept {
   size_t numElements = 1;
   for (IOBuf* current = next_; current != this; current = current->next_) {
     ++numElements;
@@ -689,7 +689,7 @@ size_t IOBuf::countChainElements() const {
   return numElements;
 }
 
-std::size_t IOBuf::computeChainDataLength() const {
+std::size_t IOBuf::computeChainDataLength() const noexcept {
   std::size_t fullLength = length_;
   for (IOBuf* current = next_; current != this; current = current->next_) {
     fullLength += current->length_;
@@ -697,7 +697,7 @@ std::size_t IOBuf::computeChainDataLength() const {
   return fullLength;
 }
 
-std::size_t IOBuf::computeChainCapacity() const {
+std::size_t IOBuf::computeChainCapacity() const noexcept {
   std::size_t fullCapacity = capacity_;
   for (IOBuf* current = next_; current != this; current = current->next_) {
     fullCapacity += current->capacity_;
@@ -1411,7 +1411,7 @@ IOBuf::FillIovResult IOBuf::fillIov(struct iovec* iov, size_t len) const {
   return {0, 0};
 }
 
-uint32_t IOBuf::approximateShareCountOne() const {
+uint32_t IOBuf::approximateShareCountOne() const noexcept {
   if (FOLLY_UNLIKELY(!sharedInfo_)) {
     return 1U;
   }
diff --git a/folly/io/IOBuf.h b/folly/io/IOBuf.h
index 447d02eb472..8bcc253d144 100644
--- a/folly/io/IOBuf.h
+++ b/folly/io/IOBuf.h
@@ -776,14 +776,14 @@ class IOBuf {
    *
    * @methodset Chaining
    */
-  bool empty() const;
+  bool empty() const noexcept;
 
   /**
    * Get the pointer to the start of the data.
    *
    * @methodset Access
    */
-  const uint8_t* data() const { return data_; }
+  const uint8_t* data() const noexcept { return data_; }
 
   /**
    * Get a writable pointer to the start of the data.
@@ -793,14 +793,14 @@ class IOBuf {
    *
    * @methodset Access
    */
-  uint8_t* writableData() { return data_; }
+  uint8_t* writableData() noexcept { return data_; }
 
   /**
    * Get the pointer to the end of the data.
    *
    * @methodset Access
    */
-  const uint8_t* tail() const { return data_ + length_; }
+  const uint8_t* tail() const noexcept { return data_ + length_; }
 
   /**
    * Get a writable pointer to the end of the data.
@@ -810,7 +810,7 @@ class IOBuf {
    *
    * @methodset Access
    */
-  uint8_t* writableTail() { return data_ + length_; }
+  uint8_t* writableTail() noexcept { return data_ + length_; }
 
   /**
    * Get the size of the data for this individual IOBuf in the chain.
@@ -819,7 +819,7 @@ class IOBuf {
    *
    * @methodset Buffer Capacity
    */
-  std::size_t length() const { return length_; }
+  std::size_t length() const noexcept { return length_; }
 
   /**
    * Get the amount of head room.
@@ -828,7 +828,9 @@ class IOBuf {
    *
    * @methodset Buffer Capacity
    */
-  std::size_t headroom() const { return std::size_t(data_ - buffer()); }
+  std::size_t headroom() const noexcept {
+    return std::size_t(data_ - buffer());
+  }
 
   /**
    * Get the amount of tail room.
@@ -837,7 +839,9 @@ class IOBuf {
    *
    * @methodset Buffer Capacity
    */
-  std::size_t tailroom() const { return std::size_t(bufferEnd() - tail()); }
+  std::size_t tailroom() const noexcept {
+    return std::size_t(bufferEnd() - tail());
+  }
 
   /**
    * Get the pointer to the start of the buffer.
@@ -848,7 +852,7 @@ class IOBuf {
    *
    * @methodset Access
    */
-  const uint8_t* buffer() const { return buf_; }
+  const uint8_t* buffer() const noexcept { return buf_; }
 
   /**
    * Get a writable pointer to the start of the buffer.
@@ -858,7 +862,7 @@ class IOBuf {
    *
    * @methodset Access
    */
-  uint8_t* writableBuffer() { return buf_; }
+  uint8_t* writableBuffer() noexcept { return buf_; }
 
   /**
    * Get the pointer to the end of the buffer.
@@ -869,7 +873,7 @@ class IOBuf {
    *
    * @methodset Access
    */
-  const uint8_t* bufferEnd() const { return buf_ + capacity_; }
+  const uint8_t* bufferEnd() const noexcept { return buf_ + capacity_; }
 
   /**
    * Get the total size of the buffer.
@@ -879,25 +883,25 @@ class IOBuf {
    *
    * @methodset Buffer Capacity
    */
-  std::size_t capacity() const { return capacity_; }
+  std::size_t capacity() const noexcept { return capacity_; }
 
   /**
    * Get a pointer to the next IOBuf in this chain.
    *
    * @methodset Chaining
    */
-  IOBuf* next() { return next_; }
+  IOBuf* next() noexcept { return next_; }
   /// @copydoc next()
-  const IOBuf* next() const { return next_; }
+  const IOBuf* next() const noexcept { return next_; }
 
   /**
    * Get a pointer to the previous IOBuf in this chain.
    *
    * @methodset Chaining
    */
-  IOBuf* prev() { return prev_; }
+  IOBuf* prev() noexcept { return prev_; }
   /// @copydoc prev
-  const IOBuf* prev() const { return prev_; }
+  const IOBuf* prev() const noexcept { return prev_; }
 
   /**
    * Shift the data forwards in the buffer.
@@ -919,7 +923,7 @@ class IOBuf {
    *
    * @methodset Shifting
    */
-  void advance(std::size_t amount) {
+  void advance(std::size_t amount) noexcept {
     // In debug builds, assert if there is a problem.
     assert(amount <= tailroom());
 
@@ -948,7 +952,7 @@ class IOBuf {
    *
    * @methodset Shifting
    */
-  void retreat(std::size_t amount) {
+  void retreat(std::size_t amount) noexcept {
     // In debug builds, assert if there is a problem.
     assert(amount <= headroom());
 
@@ -973,7 +977,7 @@ class IOBuf {
    *
    * @methodset Shifting
    */
-  void prepend(std::size_t amount) {
+  void prepend(std::size_t amount) noexcept {
     DCHECK_LE(amount, headroom());
     data_ -= amount;
     length_ += amount;
@@ -994,7 +998,7 @@ class IOBuf {
    *
    * @methodset Shifting
    */
-  void append(std::size_t amount) {
+  void append(std::size_t amount) noexcept {
     DCHECK_LE(amount, tailroom());
     length_ += amount;
   }
@@ -1013,7 +1017,7 @@ class IOBuf {
    *
    * @methodset Shifting
    */
-  void trimStart(std::size_t amount) {
+  void trimStart(std::size_t amount) noexcept {
     DCHECK_LE(amount, length_);
     data_ += amount;
     length_ -= amount;
@@ -1033,7 +1037,7 @@ class IOBuf {
    *
    * @methodset Shifting
    */
-  void trimEnd(std::size_t amount) {
+  void trimEnd(std::size_t amount) noexcept {
     DCHECK_LE(amount, length_);
     length_ -= amount;
   }
@@ -1049,7 +1053,7 @@ class IOBuf {
    *
    * @methodset Shifting
    */
-  void trimWritableTail(std::size_t amount) {
+  void trimWritableTail(std::size_t amount) noexcept {
     DCHECK_LE(amount, tailroom());
     capacity_ -= amount;
   }
@@ -1060,7 +1064,7 @@ class IOBuf {
    * @post  data() == buffer()
    * @post  length() == 0
    */
-  void clear() {
+  void clear() noexcept {
     data_ = writableBuffer();
     length_ = 0;
   }
@@ -1109,7 +1113,7 @@ class IOBuf {
    *
    * @methodset Chaining
    */
-  bool isChained() const {
+  bool isChained() const noexcept {
     assert((next_ == this) == (prev_ == this));
     return next_ != this;
   }
@@ -1123,7 +1127,7 @@ class IOBuf {
    *
    * @methodset Chaining
    */
-  size_t countChainElements() const;
+  size_t countChainElements() const noexcept;
 
   /**
    * Get the length of all the data in this IOBuf chain.
@@ -1132,7 +1136,7 @@ class IOBuf {
    *
    * @methodset Chaining
    */
-  std::size_t computeChainDataLength() const;
+  std::size_t computeChainDataLength() const noexcept;
 
   /**
    * Get the capacity all IOBufs in the chain.
@@ -1141,7 +1145,7 @@ class IOBuf {
    *
    * @methodset Chaining
    */
-  std::size_t computeChainCapacity() const;
+  std::size_t computeChainCapacity() const noexcept;
 
   /**
    * Append another IOBuf chain to the end of this chain.
@@ -1302,7 +1306,7 @@ class IOBuf {
    *
    * @methodset Buffer Management
    */
-  bool isShared() const {
+  bool isShared() const noexcept {
     const IOBuf* current = this;
     while (true) {
       if (current->isSharedOne()) {
@@ -1385,7 +1389,7 @@ class IOBuf {
    *
    * @methodset Buffer Management
    */
-  bool isManaged() const {
+  bool isManaged() const noexcept {
     const IOBuf* current = this;
     while (true) {
       if (!current->isManagedOne()) {
@@ -1429,7 +1433,7 @@ class IOBuf {
    *
    * @methodset Buffer Management
    */
-  uint32_t approximateShareCountOne() const;
+  uint32_t approximateShareCountOne() const noexcept;
 
   /**
    * Check if the buffer is shared.
diff --git a/folly/io/IOBufQueue.cpp b/folly/io/IOBufQueue.cpp
index 004a7569775..13346847c88 100644
--- a/folly/io/IOBufQueue.cpp
+++ b/folly/io/IOBufQueue.cpp
@@ -94,7 +94,7 @@ IOBufQueue::IOBufQueue(IOBufQueue&& other) noexcept
   localCache_.attached = true;
 }
 
-IOBufQueue& IOBufQueue::operator=(IOBufQueue&& other) {
+IOBufQueue& IOBufQueue::operator=(IOBufQueue&& other) noexcept {
   if (&other != this) {
     other.clearWritableRangeCache();
     clearWritableRangeCache();
diff --git a/folly/io/IOBufQueue.h b/folly/io/IOBufQueue.h
index d7d53f6f78c..208ff63e1e8 100644
--- a/folly/io/IOBufQueue.h
+++ b/folly/io/IOBufQueue.h
@@ -66,23 +66,19 @@ class IOBufQueue {
   }
 
   struct WritableRangeCacheData {
-    std::pair<uint8_t*, uint8_t*> cachedRange;
-    bool attached{false};
+    std::pair<uint8_t*, uint8_t*> cachedRange{};
+    bool attached{};
 
     WritableRangeCacheData() = default;
 
-    WritableRangeCacheData(WritableRangeCacheData&& other)
+    WritableRangeCacheData(WritableRangeCacheData&& other) noexcept
         : cachedRange(other.cachedRange), attached(other.attached) {
-      other.cachedRange = {nullptr, nullptr};
-      other.attached = false;
+      other.cachedRange = {};
+      other.attached = {};
     }
-    WritableRangeCacheData& operator=(WritableRangeCacheData&& other) {
-      cachedRange = other.cachedRange;
-      attached = other.attached;
-
-      other.cachedRange = {nullptr, nullptr};
-      other.attached = false;
-
+    WritableRangeCacheData& operator=(WritableRangeCacheData&& other) noexcept {
+      cachedRange = std::exchange(other.cachedRange, {});
+      attached = std::exchange(other.attached, {});
       return *this;
     }
 
@@ -133,7 +129,7 @@ class IOBufQueue {
      * Move constructor/assignment can move the cached range, but must update
      * the reference in IOBufQueue.
      */
-    WritableRangeCache(WritableRangeCache&& other)
+    WritableRangeCache(WritableRangeCache&& other) noexcept
         : data_(std::move(other.data_)), queue_(other.queue_) {
       if (data_.attached) {
         queue_->updateCacheRef(data_);
@@ -218,7 +214,7 @@ class IOBufQueue {
     /**
      * Mark n bytes as occupied (e.g. postallocate).
      */
-    void append(size_t n) {
+    void append(size_t n) noexcept {
       dcheckIntegrity();
       // This can happen only if somebody is misusing the interface.
       // E.g. calling append after touching IOBufQueue or without checking
@@ -426,7 +422,7 @@ class IOBufQueue {
    *       invoke any other non-const methods on this IOBufQueue between
    *       the call to preallocate and the call to postallocate().
    */
-  void postallocate(std::size_t n) {
+  void postallocate(std::size_t n) noexcept {
     dcheckCacheIntegrity();
     DCHECK_LE(
         (void*)(cachePtr_->cachedRange.first + n),
@@ -632,7 +628,7 @@ class IOBufQueue {
 
   /** Movable */
   IOBufQueue(IOBufQueue&&) noexcept;
-  IOBufQueue& operator=(IOBufQueue&&);
+  IOBufQueue& operator=(IOBufQueue&&) noexcept;
 
   static constexpr size_t kMaxPackCopy = 4096;
 
@@ -661,7 +657,7 @@ class IOBufQueue {
   WritableRangeCacheData* cachePtr_{nullptr};
   WritableRangeCacheData localCache_;
 
-  void dcheckCacheIntegrity() const {
+  void dcheckCacheIntegrity() const noexcept {
     // Tail start should always be less than tail end.
     DCHECK_LE((void*)tailStart_, (void*)cachePtr_->cachedRange.first);
     DCHECK_LE(
@@ -689,7 +685,7 @@ class IOBufQueue {
   /**
    * Populate dest with writable tail range cache.
    */
-  void fillWritableRangeCache(WritableRangeCacheData& dest) {
+  void fillWritableRangeCache(WritableRangeCacheData& dest) noexcept {
     dcheckCacheIntegrity();
     if (cachePtr_ != &dest) {
       dest = std::move(*cachePtr_);
@@ -700,7 +696,7 @@ class IOBufQueue {
   /**
    * Clear current writable tail cache and reset it to localCache_
    */
-  void clearWritableRangeCache() {
+  void clearWritableRangeCache() noexcept {
     flushCache();
 
     if (cachePtr_ != &localCache_) {
@@ -714,7 +710,7 @@ class IOBufQueue {
   /**
    * Commit any pending changes to the tail of the queue.
    */
-  void flushCache() const {
+  void flushCache() const noexcept {
     dcheckCacheIntegrity();
 
     if (tailStart_ != cachePtr_->cachedRange.first) {
@@ -730,12 +726,14 @@ class IOBufQueue {
   }
 
   // For WritableRangeCache move assignment/construction.
-  void updateCacheRef(WritableRangeCacheData& newRef) { cachePtr_ = &newRef; }
+  void updateCacheRef(WritableRangeCacheData& newRef) noexcept {
+    cachePtr_ = &newRef;
+  }
 
   /**
    * Update cached writable tail range. Called by updateGuard()
    */
-  void updateWritableTailCache() {
+  void updateWritableTailCache() noexcept {
     if (FOLLY_LIKELY(head_ != nullptr)) {
       IOBuf* buf = head_->prev();
       if (FOLLY_LIKELY(!buf->isSharedOne())) {