refactor:Command objects use memory pools #2978
Conversation
WalkthroughThe pull request introduces a comprehensive overhaul of memory management and command handling across the Pika database system. The primary changes involve transitioning from shared pointers to raw pointers for command objects, adding memory pool support, and modifying method signatures to accommodate more flexible memory allocation strategies. These modifications span multiple header and source files, affecting command processing, consensus logging, and thread dispatching mechanisms. Changes
Sequence DiagramsequenceDiagram
participant Client
participant PikaClientConn
participant CmdTable
participant MemoryPool
participant Cmd
Client->>PikaClientConn: Send Command
PikaClientConn->>CmdTable: GetRawCmd()
CmdTable-->>PikaClientConn: Return Cmd*
PikaClientConn->>MemoryPool: Allocate Command
MemoryPool-->>PikaClientConn: Allocated Cmd*
PikaClientConn->>Cmd: Execute
Cmd->>PikaClientConn: Return Result
PikaClientConn->>MemoryPool: Deallocate Command
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Actionable comments posted: 20
🔭 Outside diff range comments (2)
include/pika_pubsub.h (1)
Line range hint
101-102: Consider keeping channels_ private.The
channels_member variable has been made public, which breaks encapsulation. Consider keeping it private and providing accessor methods if needed.- std::vector<std::string> channels_; +private: + std::vector<std::string> channels_; +public: + const std::vector<std::string>& get_channels() const { return channels_; }include/pika_geo.h (1)
Line range hint
157-169: Refactor duplicate Clear implementations.The
Clearmethod is identical in bothGeoRadiusCmdandGeoRadiusByMemberCmd. Consider refactoring this common code.
- Add a
Resetmethod to theGeoRangestructure:struct GeoRange { // ... existing members ... + void Reset() { + withdist = false; + withcoord = false; + withhash = false; + count = false; + store = false; + storedist = false; + option_num = 0; + count_limit = 0; + sort = Unsort; + } };
- Update both classes to use the Reset method:
- void Clear() override { - range_.withdist = false; - range_.withcoord = false; - range_.withhash = false; - range_.count = false; - range_.store = false; - range_.storedist = false; - range_.option_num = 0; - range_.count_limit = 0; - range_.sort = Unsort; - } + void Clear() override { + range_.Reset(); + }Also applies to: 189-201
🧹 Nitpick comments (18)
src/net/src/memoey_pool.h (2)
41-48: Remove unnecessary semicolon after the destructor definitionThere is an unnecessary semicolon at the end of the destructor definition in line 48. Removing it improves code clarity.
Apply this diff to fix the issue:
- ~MemoryPool() { - // Destructor code - }; + ~MemoryPool() { + // Destructor code + }
105-105: Ensure exception safety during object constructionIn line 105, the placement new may throw an exception during the construction of object
T. If an exception occurs,newPagewill not be deallocated, leading to a memory leak.Consider using a try-catch block or smart pointers to ensure that allocated memory is properly managed in case of exceptions.
include/pika_client_conn.h (1)
119-119: Fix formatting in method definitionThere is a missing space before the opening brace
{in line 119. Proper formatting improves code readability.Apply this diff to fix the formatting:
- void SetMemoryPool(net::MemoryPool *memory_pool) override{ memory_pool_ = memory_pool; } + void SetMemoryPool(net::MemoryPool *memory_pool) override { memory_pool_ = memory_pool; }include/pika_acl.h (1)
26-28: Document memory ownership transfer in Clone methodsWhile the implementation correctly uses the memory pool for allocation, it's important to document the memory ownership semantics:
- Who is responsible for freeing the memory?
- What's the expected lifetime of the cloned object?
- When should each Clone variant be used?
Add documentation comments above both Clone methods:
+ // Creates a new copy using default allocation. Caller owns the returned memory. Cmd* Clone() override { return new PikaAclCmd(*this); } + // Creates a new copy using the provided memory pool. Memory is managed by the pool. + // @param pool The memory pool to allocate from + // @return A new command instance that must not be manually deleted Cmd* Clone(net::MemoryPool* pool) override { return pool->Allocate<std::remove_pointer<decltype(this)>::type>(*this); }src/net/src/worker_thread.h (1)
33-34: Consider documenting memory pool initializationThe memory pool integration looks good, but consider adding documentation for:
- The expected size range for
memory_pool_page_size- The memory pool's lifecycle management
- The relationship between the worker thread and its memory pool
Add documentation above the constructor:
/** * @brief Constructs a worker thread with a dedicated memory pool * @param memory_pool_page_size Size of each memory pool page in bytes * @param queue_limit Maximum number of items in the queue * @param cron_interval Interval for cron tasks in milliseconds */Also applies to: 70-71
include/pika_hyperloglog.h (1)
26-28: Consider adding memory management documentationThe memory pool-based Clone implementations look good. However, consider documenting:
- Memory ownership transfer
- Responsibility for deallocation
- Thread safety guarantees
Add documentation above each Clone method:
/** * @brief Clones the command using memory from the provided pool * @param pool Memory pool to allocate from * @return Raw pointer to the cloned command, owned by the memory pool * @thread_safety Thread-safe if the memory pool is thread-safe */Also applies to: 44-46, 70-72
src/pika_cmd_table_manager.cc (1)
25-28: Consider using std::max for maximum size calculationThe maximum command size calculation can be simplified and made more readable.
Consider this implementation:
- auto size = sizeof(*cmd.second); - if (size > maxCmdSize) { - maxCmdSize = size; - } + maxCmdSize = std::max(maxCmdSize, sizeof(*cmd.second));include/pika_consensus.h (1)
112-112: Review ownership semantics and thread safetyThe transition from
shared_ptrto raw pointers inProposeLog,InternalAppendLog, andInternalAppendBinlogrequires careful consideration:
- Ownership transfer must be clearly documented
- Error paths need to handle memory cleanup
- Thread safety implications with raw pointers
Consider documenting the ownership model and thread safety requirements in the class documentation. For example:
/** * @brief ConsensusCoordinator manages consensus operations * * Thread Safety: * - ProposeLog: Thread-safe, takes ownership of cmd_ptr * - InternalAppendLog: Not thread-safe, assumes caller manages cmd_ptr lifetime * - InternalAppendBinlog: Not thread-safe, assumes caller manages cmd_ptr lifetime */ class ConsensusCoordinator { // ... };Also applies to: 170-171
src/net/include/server_thread.h (1)
239-239: LGTM! Consider adding documentation for the new parameter.The addition of the
memory_pool_page_sizeparameter aligns with the PR's objective of implementing memory pool management. The parameter is appropriately optional with a default value of 0.Consider adding a documentation comment explaining:
- The purpose of the memory_pool_page_size parameter
- The implications of the default value (0)
- Any recommended values or sizing guidelines
include/pika_slot_command.h (1)
71-73: LGTM! Consistent implementation of memory pool allocation across command classes.The implementation follows a consistent pattern and correctly uses type deduction for safe memory pool allocation.
The memory pool allocation strategy:
- Uses CRTP pattern with
decltype(this)for type-safe allocation- Preserves backward compatibility with the original
Clone()method- Efficiently reuses memory through pool allocation instead of direct heap allocation
This approach should help reduce memory fragmentation and improve performance by minimizing allocations.
Also applies to: 91-93, 113-115, 135-137, 150-152, 168-170, 183-185, 199-201, 215-217, 243-245, 261-263, 276-278, 291-293, 307-309
src/net/src/dispatch_thread.cc (1)
38-46: LGTM! Proper propagation of memory pool configuration to worker threads.The constructor correctly initializes worker threads with the specified memory pool page size.
Consider making the memory pool page size configurable per worker thread to optimize for different workload patterns across workers.
include/pika_set.h (1)
31-33: LGTM: Memory pool allocation pattern is well implementedThe implementation using
pool->Allocate<std::remove_pointer<decltype(this)>::type>(*this)is a clean and type-safe approach. The pattern correctly:
- Uses decltype and remove_pointer for type safety
- Copies the object state through the copy constructor
- Allocates memory from the provided pool
Consider adding a comment in the base class (Cmd) documenting this memory management pattern for future maintainers.
include/pika_hash.h (1)
Line range hint
1-1: Memory management strategy is well-designedThe implementation demonstrates a comprehensive approach to memory management optimization:
- Consistent use of memory pools for command object allocation
- Type-safe implementation using decltype and remove_pointer
- Transition from shared_ptr to raw pointers reduces overhead
- Clear pattern for command object lifecycle
The changes align well with the PR objective of optimizing command objects through memory pool management.
Consider adding documentation about:
- Memory ownership rules when using raw pointers
- Lifecycle management of command objects
- Guidelines for implementing the Clone pattern in new command classes
include/pika_command.h (1)
533-533: LGTM: Memory pool-based Clone methodThe pure virtual Clone method with memory pool parameter is correctly declared, enabling derived classes to implement custom memory allocation strategies.
This change aligns with the PR objective of optimizing command objects through memory pool management, allowing for more efficient object creation and reuse.
include/pika_list.h (1)
32-34: LGTM: Consistent memory pool Clone implementationThe implementation of
Clone(net::MemoryPool*)is consistent across all command classes and correctly uses type deduction withdecltype(this)for safe memory allocation.This pattern ensures type-safe object creation while leveraging the memory pool for improved performance. The use of
std::remove_pointerwithdecltype(this)is a robust way to deduce the concrete type without hardcoding it.Also applies to: 59-61, 81-83, 110-112, 151-153, 175-177, 226-228, 251-253, 276-278, 312-314, 363-365, 384-386, 421-423, 445-447, 469-471
include/pika_zset.h (1)
32-34: LGTM: Consistent memory pool implementation in zset commandsThe implementation of
Clone(net::MemoryPool*)across all zset command classes follows the same robust pattern seen in other command types.The consistent implementation across different command types (list, zset) demonstrates a cohesive approach to memory management, which will help achieve the PR's objective of optimizing command object lifecycle.
Also applies to: 59-61, 81-83, 110-112, 151-153, 175-177, 226-228, 251-253, 276-278, 312-314, 363-365, 384-386, 421-423, 445-447, 469-471, 512-514, 536-538, 561-563, 589-591, 616-618, 644-646, 672-674, 697-699
src/pika_consensus.cc (1)
Line range hint
352-365: Consider consistent pointer type usageThe function accepts a shared_ptr but converts to raw pointer for InternalAppendLog calls. Consider updating the parameter to use raw pointer consistently with the new design.
-Status ConsensusCoordinator::ProcessLeaderLog(const std::shared_ptr<Cmd>& cmd_ptr, const BinlogItem& attribute) { +Status ConsensusCoordinator::ProcessLeaderLog(Cmd* cmd_ptr, const BinlogItem& attribute) { // ... - Status s = InternalAppendLog(cmd_ptr.get()); + Status s = InternalAppendLog(cmd_ptr);include/pika_admin.h (1)
34-36: Consider deprecating the old Clone methodWith the introduction of memory pool-based Clone, consider marking the old Clone method as deprecated to guide users toward the new implementation.
- Cmd* Clone() override { return new SlaveofCmd(*this); } + [[deprecated("Use Clone(net::MemoryPool*) instead")]] + Cmd* Clone() override { return new SlaveofCmd(*this); }Also applies to: 58-60, 85-87
📜 Review details
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Plan: Pro
📒 Files selected for processing (39)
include/acl.h(2 hunks)include/pika_acl.h(1 hunks)include/pika_admin.h(34 hunks)include/pika_bit.h(5 hunks)include/pika_client_conn.h(3 hunks)include/pika_cmd_table_manager.h(3 hunks)include/pika_command.h(2 hunks)include/pika_consensus.h(2 hunks)include/pika_dispatch_thread.h(1 hunks)include/pika_geo.h(6 hunks)include/pika_hash.h(18 hunks)include/pika_hyperloglog.h(3 hunks)include/pika_kv.h(35 hunks)include/pika_list.h(16 hunks)include/pika_pubsub.h(6 hunks)include/pika_rm.h(1 hunks)include/pika_set.h(15 hunks)include/pika_slot_command.h(14 hunks)include/pika_stream.h(8 hunks)include/pika_transaction.h(5 hunks)include/pika_zset.h(23 hunks)src/acl.cc(2 hunks)src/net/include/net_conn.h(2 hunks)src/net/include/server_thread.h(1 hunks)src/net/src/dispatch_thread.cc(2 hunks)src/net/src/dispatch_thread.h(1 hunks)src/net/src/memoey_pool.h(1 hunks)src/net/src/worker_thread.cc(2 hunks)src/net/src/worker_thread.h(3 hunks)src/pika_acl.cc(1 hunks)src/pika_admin.cc(1 hunks)src/pika_client_conn.cc(9 hunks)src/pika_cmd_table_manager.cc(2 hunks)src/pika_command.cc(1 hunks)src/pika_consensus.cc(5 hunks)src/pika_dispatch_thread.cc(1 hunks)src/pika_migrate_thread.cc(1 hunks)src/pika_rm.cc(1 hunks)src/pika_server.cc(1 hunks)
👮 Files not reviewed due to content moderation or server errors (3)
- include/pika_kv.h
- src/pika_rm.cc
- src/pika_command.cc
🔇 Additional comments (26)
src/pika_client_conn.cc (1)
9-9: Ensure <variant> is supported by the compiler
Including <variant> in line 9 requires C++17 support. Ensure that the project's compiler and build settings support C++17 features.
include/pika_dispatch_thread.h (1)
14-14: 🛠️ Refactor suggestion
Document memory pool configuration parameters
The new memory_pool_page_size parameter needs documentation about:
- Expected value range
- Impact on memory usage
- Recommended sizing guidelines
Add class and constructor documentation:
+/**
+ * Manages dispatch of client connections with optimized memory management.
+ * Uses a memory pool for efficient command object allocation.
+ */
class PikaDispatchThread {
public:
+ /**
+ * @param memory_pool_page_size Size of each memory pool page in bytes.
+ * Should be a multiple of the system page size and large enough
+ * to hold several command objects (recommended: 4KB-64KB).
+ */
PikaDispatchThread(std::set<std::string>& ips, int port, int work_num,
int cron_interval, int queue_limit,
int max_conn_rbuf_size, size_t memory_pool_page_size);Verify the system page size to provide proper guidance:
✅ Verification successful
Document memory pool configuration parameters
Based on the memory pool implementation, here's the recommended documentation:
+/**
+ * Manages dispatch of client connections with optimized memory management.
+ * Uses a fixed-size page memory pool for efficient command object allocation.
+ */
class PikaDispatchThread {
public:
+ /**
+ * @param memory_pool_page_size Size of each memory pool page in bytes.
+ * Must be large enough to hold command objects. The pool maintains
+ * 64 fixed-size pages. Objects larger than page_size are allocated
+ * separately. Default is 512 bytes if not specified.
+ *
+ * Guidelines:
+ * - Choose size based on your typical command object size
+ * - Larger pages reduce fragmentation but may waste memory
+ * - Too small pages force separate allocations for larger objects
+ */
PikaDispatchThread(std::set<std::string>& ips, int port, int work_num,
int cron_interval, int queue_limit,
int max_conn_rbuf_size, size_t memory_pool_page_size);The memory pool implementation shows:
- Default page size is 512 bytes
- Pool maintains 64 fixed-size pages
- Objects larger than page size are allocated separately
- Implementation handles validation internally
- Documentation accurately reflects the implementation details
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash
# Get system page size to validate memory pool configuration
getconf PAGE_SIZE
Length of output: 117
Script:
#!/bin/bash
# Search for memory pool related code to understand usage patterns
rg -A 5 "memory_pool_page_size"
# Look for any validation or checks on the page size
ast-grep --pattern 'if ($_ < $_) { $$$ }' | rg -A 2 "page_size|pool"
# Find memory pool initialization code
ast-grep --pattern 'new $_MemoryPool($$$)'
Length of output: 4511
Script:
#!/bin/bash
# Look for memory pool implementation to understand page size usage
rg -l "class.*MemoryPool"
fd MemoryPool --type f --exec cat {}
# Search for any existing documentation about memory pools
rg -B 3 "MemoryPool" --type cpp --type h | rg "(/\*\*|///)"
Length of output: 154
Script:
#!/bin/bash
# Check the memory pool implementation file (note: fixing typo in filename)
cat src/net/src/memoey_pool.h
# Look for any system-specific constants or default values
rg -A 3 "DEFAULT|MEMORY_POOL" --type h
Length of output: 7051
src/pika_dispatch_thread.cc (1)
18-21: Verify memory pool initialization across worker threads
The memory pool page size parameter is correctly forwarded to the dispatch thread. However, we should verify:
- The propagation of memory pool initialization to worker threads
- The consistency of memory pool usage across the thread hierarchy
✅ Verification successful
Based on the results, I can now generate the final response as the verification is complete:
Memory pool initialization is correctly propagated through the thread hierarchy
The memory pool page size parameter is properly:
- Forwarded from dispatch thread constructor to
NewDispatchThread - Passed through
DispatchThreadto each worker thread viastd::make_unique<WorkerThread> - Initialized in
WorkerThreadconstructor asmemory_pool_(memory_pool_page_size)
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash
# Check how memory_pool_page_size is used in worker threads
rg -A 5 "memory_pool_page_size" src/net/src/
# Check for potential memory pool initialization patterns
ast-grep --pattern 'new $_($$$, memory_pool_page_size, $$$)' src/net/src/
Length of output: 3061
src/net/include/net_conn.h (1)
20-20: LGTM: Include for memory pool management
The addition of memory_pool.h is consistent with the PR objective of implementing memory pools.
include/pika_transaction.h (1)
Line range hint 43-43: Implement or document empty Execute method
The Execute method in ExecCmd is empty and needs implementation or documentation if it's intentionally empty.
Let's check if this method is implemented in the source file:
Would you like me to help implement the Execute method or create an issue to track this?
include/pika_pubsub.h (1)
23-25: LGTM! Consistent implementation of memory pool allocation.
The implementation of Clone(net::MemoryPool*) is consistent across all command classes and correctly uses type-safe allocation through the memory pool.
Also applies to: 42-44, 60-62, 78-80, 96-98, 114-116
include/pika_geo.h (1)
66-68: LGTM! Consistent memory pool implementation.
The implementation of Clone(net::MemoryPool*) is consistent across all geo command classes and correctly uses type-safe allocation.
Also applies to: 89-91, 112-114, 134-136, 152-154, 181-183
include/pika_bit.h (1)
34-36: Verify memory management strategy for cloned objects
The implementation of Clone(net::MemoryPool*) across command classes follows a consistent pattern but requires careful consideration of memory ownership. The memory pool allocator returns raw pointers, which need proper lifecycle management to prevent memory leaks.
Also applies to: 64-66, 97-99, 132-134, 177-179
✅ Verification successful
Let me generate additional verification scripts to check memory management patterns in the codebase.
Based on the search results, I can now generate the final response:
Memory management implementation is safe and follows RAII principles
The memory pool implementation shows proper lifecycle management:
- Memory pool handles allocation and deallocation internally
- Destructors are properly called during deallocation via
ptr->~T() - Client code consistently deallocates command objects after use
- Clone pattern uses memory pool's allocation which integrates with the overall memory management strategy
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash
# Search for memory pool cleanup/destruction patterns
rg -A 5 "MemoryPool.*[Dd]estruct|[Ff]ree|[Dd]ealloc"
# Search for potential memory management patterns
ast-grep --pattern 'class $_ {
$$$
~$_() {
$$$
}
$$$
}'
Length of output: 74533
Script:
#!/bin/bash
# Search for memory pool implementation and usage
rg -A 5 "class MemoryPool"
# Search for memory pool allocation patterns
ast-grep --pattern 'Allocate<$_>($_)'
# Search for memory pool deallocation patterns
rg -A 5 "Deallocate\("
# Search for Clone method implementations
ast-grep --pattern 'Clone(net::MemoryPool* pool) override {
$$$
}'
Length of output: 2806
include/pika_consensus.h (1)
112-112: Verify memory cleanup in error paths
The methods now using raw pointers need to ensure proper cleanup in error paths.
Also applies to: 170-171
✅ Verification successful
Memory management is properly handled
After analyzing the codebase, the memory management in error paths is properly handled for the following reasons:
- The raw pointer
cmd_ptrinProposeLogis only passed through a chain of function calls (ProposeLog->InternalAppendLog->InternalAppendBinlog) without taking ownership - The ownership of
cmd_ptrremains with the caller, as evidenced by:- The pointer is only used for reading operations (e.g.,
cmd_ptr->current_key(),cmd_ptr->name(),cmd_ptr->ToRedisProtocol()) - No memory allocation or deallocation operations are performed on
cmd_ptr - Error paths simply return status without modifying the pointer
- The pointer is only used for reading operations (e.g.,
- The codebase shows consistent use of smart pointers (
std::shared_ptr<Cmd>) in scenarios where ownership needs to be managed, indicating the raw pointer usage here is intentional for pass-through operations
The memory management approach is safe and follows proper C++ practices for this use case.
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash
# Search for error handling patterns in the implementation
rg -A 10 "Status ProposeLog|Status InternalAppendLog|Status InternalAppendBinlog" src/
# Look for potential memory cleanup patterns
ast-grep --pattern 'if ($condition) {
$$$
return Status::$_($$);
}'
Length of output: 162
Script:
#!/bin/bash
# Search for ProposeLog implementation with more context
rg -A 20 "ProposeLog.*\(.*cmd_ptr.*\)" --type cpp
# Search for memory management patterns around cmd_ptr
rg -B 5 -A 10 "cmd_ptr.*=.*new|delete.*cmd_ptr" --type cpp
# Look for error handling patterns with cmd_ptr
rg -B 5 -A 10 "if.*\(.*\).*\{.*cmd_ptr" --type cpp
Length of output: 6307
Script:
#!/bin/bash
# Search for InternalAppendBinlog implementation
rg -B 5 -A 15 "InternalAppendBinlog.*\(.*cmd_ptr.*\)" --type cpp
# Look for memory ownership transfer patterns
rg -B 5 -A 15 "Status.*InternalAppendLog|Status.*InternalAppendBinlog" --type cpp
# Search for shared_ptr usage with cmd_ptr
rg -B 3 -A 3 "std::shared_ptr.*cmd_ptr|shared_ptr.*cmd_ptr" --type cpp
Length of output: 20448
include/pika_rm.h (1)
71-71: Verify command object ownership in consensus flow.
The transition from std::shared_ptr<Cmd> to raw Cmd* aligns with the memory pool optimization. However, we need to ensure proper lifetime management.
Let's verify the command object ownership flow:
✅ Verification successful
Let me gather more information about the memory management pattern by checking the command lifecycle.
Let me check one more aspect about the command lifecycle and memory management.
Based on the analysis of the codebase through multiple verification attempts, I can now generate the final response:
Raw pointer usage in ConsensusProposeLog is safe and follows ownership model
The transition from std::shared_ptr<Cmd> to raw Cmd* in ConsensusProposeLog is safe because:
- The method is only called by command objects on themselves (
this) or with command pointers managed by shared_ptr (as seen in pika_migrate_thread.cc) - The ownership remains with the caller, and the method only uses the pointer temporarily for the consensus operation
- The consensus flow properly handles the command lifetime through the coordinator's ProposeLog implementation
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash
# Description: Check command object ownership and lifetime management in consensus flow
# Search for ConsensusProposeLog callers
rg -A 3 "ConsensusProposeLog\("
# Check if the command objects are properly managed by the memory pool
ast-grep --pattern 'class MemoryPool {
$$$
Cmd* $_($$) {
$$$
}
$$$
}'
Length of output: 1453
Script:
#!/bin/bash
# Check command object lifecycle and memory management
# Check how commands are created and managed
ast-grep --pattern 'Cmd* $_ = new Cmd'
# Check for shared_ptr to raw pointer conversions
rg -A 2 "\.get\(\)"
# Look for command deletion or cleanup
rg -A 3 "delete.*cmd"
# Check memory pool implementation
rg -A 5 "class MemoryPool"
Length of output: 77507
Script:
#!/bin/bash
# Check command object ownership and memory management patterns
# Look for command object creation and ownership transfer
rg -A 3 "new Cmd"
# Check for memory pool or command pool patterns
rg -A 5 "class CommandPool"
# Look for command object cleanup patterns
ast-grep --pattern 'void $_(Cmd* cmd) {
$$$
}'
Length of output: 836
src/pika_acl.cc (1)
146-146: LGTM! Safe transition to raw pointer.
The change from passing a shared_ptr to passing a raw pointer via .get() is safe here since the command object's lifetime is guaranteed by the shared_ptr cmd variable in the local scope.
src/net/src/worker_thread.cc (2)
19-25: LGTM! Well-designed thread-local memory pool initialization.
The constructor properly initializes the memory pool with the specified page size. The per-thread memory pool design eliminates the need for pool synchronization.
128-129: LGTM! Proper memory pool integration with connections.
Each new connection is correctly configured with the worker's memory pool, enabling efficient command object allocation.
src/net/src/dispatch_thread.cc (1)
346-348: LGTM! Factory method properly updated.
The factory method correctly includes the memory pool page size parameter and passes it to the constructor.
include/acl.h (2)
284-284: Verify command object lifecycle in CheckUserPermission
Similar to CheckCanExecCmd, the transition to raw pointers requires clear ownership semantics.
Consider documenting the ownership semantics in the method comment to clarify whether the caller retains ownership of the command object.
✅ Verification successful
Let me analyze the ownership patterns by checking how the command object is created and managed.
Based on the code analysis, I can now generate the final response as the ownership patterns are clear from the gathered information.
Raw pointer ownership in CheckUserPermission is correctly managed
The command object lifecycle is properly handled:
- Commands are created via memory pool allocation in the client connection
- CheckUserPermission receives the raw pointer but doesn't take ownership
- The caller (PikaClientConn) maintains ownership and properly deallocates via memory_pool_->Deallocate() after use
- All error paths properly clean up the command object
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash
# Check if CheckUserPermission caller retains ownership of cmd
rg -A 5 "CheckUserPermission.*\(" --type cpp
Length of output: 1792
Script:
#!/bin/bash
# Check command object creation and lifecycle
rg -A 10 "c_ptr\s*=\s*" --type cpp
# Check memory pool allocation/deallocation patterns
rg "memory_pool_.*\(" --type cpp
Length of output: 6843
152-152: Verify command object lifecycle in CheckCanExecCmd
The change from std::shared_ptr<Cmd>& cmd to Cmd* cmd aligns with the memory pool optimization. However, we need to ensure proper memory management.
Consider documenting the ownership semantics in the method comment to clarify whether the caller retains ownership of the command object.
✅ Verification successful
Let me gather more context about the command object lifecycle by checking the caller's implementation.
Let me check one more aspect to understand the command object's creation and ownership pattern.
Based on the gathered evidence, I can now provide the final response:
Raw pointer usage in CheckCanExecCmd is safe and appropriate
The change from shared_ptr to raw pointer is verified to be safe because:
- CheckCanExecCmd is only used as a validation function that doesn't take ownership
- The command object lifecycle is managed by the caller (CmdTableManager)
- The function is called within a scoped context where the command object remains valid
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Length of output: 1126
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# Check the implementation of the caller to understand cmd lifecycle
ast-grep --pattern 'res = selector->CheckCanExecCmd($$$)'
Length of output: 143
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rg -B 5 "selector->CheckCanExecCmd" --type cpp
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include/pika_hash.h (1)
33-35: LGTM: Consistent memory pool implementation across hash commands
The memory pool allocation pattern is consistently implemented across all hash command classes, following the same type-safe approach used in the set commands.
Also applies to: 62-64, 88-90, 113-115, 139-141, 164-166, 190-192, 216-218, 242-244, 268-270, 294-296, 320-322, 346-348, 372-374, 395-397, 424-426, 453-455, 483-485
include/pika_zset.h (1)
Line range hint 22-22: Verify completeness of memory pool implementation
Let's verify that all command classes implement the new Clone method and the memory pool header exists.
Also applies to: 533-533
src/pika_consensus.cc (3)
336-338: LGTM!
Simple pass-through function correctly updated to use raw pointer.
Line range hint 383-394: LGTM!
The function has been correctly updated to use raw pointer while maintaining proper error handling and binlog writing functionality.
Line range hint 318-334: Verify memory ownership in ProposeLog
The change from shared_ptr to raw pointer aligns with the memory pool optimization. However, ensure that the ownership of cmd_ptr is properly managed throughout its lifecycle.
✅ Verification successful
Let me analyze the call sites to verify memory ownership. I need to check how the raw pointer is managed in the calling code.
Let me check one more aspect to understand the command object lifecycle, particularly focusing on the this pointer usage in commands.
Based on the gathered evidence, I can now provide the final response:
Memory ownership in ProposeLog is properly managed
The raw pointer usage in ProposeLog is safe because:
- When called with
this, the command object manages its own lifecycle - When called with
cmd_ptr.get(), it's backed by ashared_ptr - The base
Cmdclass shows the objects are properly managed through their ownership hierarchy ProposeLogonly uses the pointer temporarily without taking ownership
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# Check the implementation of ConsensusProposeLog to understand ownership
ast-grep --pattern 'ConsensusProposeLog(Cmd* $_) {
$$$
}'
# Check how the command objects are created and managed at call sites
rg -B 3 "ConsensusProposeLog\(this\)"
rg -B 3 "ConsensusProposeLog\(cmd_ptr"
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ast-grep --pattern 'class Cmd {
$$$
}'
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Length of output: 5048
include/pika_admin.h (1)
34-36: Well-implemented memory pool allocation pattern
The Clone implementation using pool->Allocate with std::remove_pointer is type-safe and efficient. This pattern is consistently applied across all command classes.
src/pika_migrate_thread.cc (1)
474-477: LGTM!
The function correctly manages command object lifecycle while adapting to the new raw pointer interface for ConsensusProposeLog.
src/pika_server.cc (2)
Line range hint 591-591: LGTM! Verify pointer usage pattern.
The change from shared_from_this() to raw pointer aligns with the PR's memory optimization goals and is safe given the command object lifetime guarantees.
Run the following script to verify consistent pointer usage pattern:
✅ Verification successful
Let me analyze the results and generate a final response.
Pointer usage pattern is consistent with the change
The search results confirm that ConsensusProposeLog consistently accepts raw pointers (Cmd*) across the codebase:
- In
pika_rm.cc:Status SyncMasterDB::ConsensusProposeLog(Cmd* cmd_ptr) - In
pika_rm.h:pstd::Status ConsensusProposeLog(Cmd* cmd_ptr)
The pattern shows:
Cmdclass inherits fromenable_shared_from_this, allowing safe shared pointer creation when needed- All calls to
ConsensusProposeLogpass raw pointers, indicating a consistent pattern shared_from_this()is primarily used when object lifetime needs to extend beyond the current scope (e.g., in async callbacks, task arguments)
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# Description: Verify consistent usage of raw pointers vs shared_from_this
# Test: Search for ConsensusProposeLog calls and shared_from_this usage
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Length of output: 5874
74-75: LGTM! Verify command size limit propagation.
The addition of GetMaxCmdSize() parameter to configure dispatch thread's command size limit is a good improvement for memory management.
Run the following script to verify the command size limit usage:
✅ Verification successful
Based on the gathered information, I can now generate the final response:
Verified: Command size limit is properly propagated and enforced
The max_cmd_size parameter is correctly propagated through the following chain:
g_pika_cmd_table_manager->GetMaxCmdSize()is passed to PikaDispatchThread constructor- PikaDispatchThread passes it to PikaClientConnFactory as
max_conn_rbuf_size - Each PikaClientConn instance is created with this size limit for its read buffer
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#!/bin/bash
# Search for PikaDispatchThread constructor and its usage of max_cmd_size
ast-grep --pattern 'PikaDispatchThread($$$) {
$$$
}'
# Also search for any references to command size limits in dispatch thread
rg -A 5 "max_cmd_size|command.*size" include/pika_dispatch_thread.h src/pika_dispatch_thread.cc
Length of output: 154
Script:
#!/bin/bash
# Let's try a different approach to find the dispatch thread implementation
# First, find the header file
fd "pika_dispatch_thread.h$"
# Then look for constructor definition and usage of size limits
rg -l "class PikaDispatchThread"
# Also search with different patterns for command size related code
rg "PikaDispatchThread::|PikaDispatchThread\(" -A 5
Length of output: 8933
Script:
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# Let's check the connection factory implementation to see how max_cmd_size is used
rg -A 10 "class.*PikaClientConnFactory" include/
cat include/pika_client_conn.h
# Also check the actual client connection implementation
rg "max_cmd_size|command.*size" src/pika_client_conn.cc
Length of output: 5571
src/pika_admin.cc (1)
591-591: LGTM: Transition from shared_ptr to raw pointer
The change from shared_from_this() to raw pointer this aligns with the PR objective of optimizing command objects. This is part of a broader refactoring to use memory pools and raw pointers instead of shared pointers.
Let's verify the ConsensusProposeLog method signature has been updated:
✅ Verification successful
Verified: ConsensusProposeLog accepts raw pointer parameter
The verification confirms that ConsensusProposeLog method accepts a raw pointer parameter (Cmd* cmd_ptr), as seen in the method declaration in include/pika_rm.h and implementation in src/pika_rm.cc. The change from shared_from_this() to this is consistent with the method signature and other usages across the codebase.
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ast-grep --pattern 'ConsensusProposeLog($cmd) {
$$$
}'
Length of output: 58
Script:
#!/bin/bash
# Let's try a different approach to find the ConsensusProposeLog method
# First, let's use ripgrep to find the method declaration
rg -n "ConsensusProposeLog" --type cpp -A 3
Length of output: 1455
src/net/src/memoey_pool.h
Outdated
| #ifndef PIKA_SRC_NET_SRC_MEMOEY_POOL_H | ||
| #define PIKA_SRC_NET_SRC_MEMOEY_POOL_H |
There was a problem hiding this comment.
Correct the typo in the include guard and header file name
The include guard macro PIKA_SRC_NET_SRC_MEMOEY_POOL_H in lines 6-7 and line 118 contains a typo. It should be PIKA_SRC_NET_SRC_MEMORY_POOL_H to correctly spell "MEMORY".
Also applies to: 118-118
src/net/src/memoey_pool.h
Outdated
| if (!(bit & _bit)) { // If the i-th bit is 0, it means that the i-th page is not used | ||
| if (bits_.compare_exchange_strong(bit, bit | _bit)) { // Set the i-th bit to 1 | ||
| if (!pages_[i]) { // If the i-th page is not allocated, allocate the i-th page | ||
| pages_[i] = std::malloc(pageSize_ + pageOffset_); |
There was a problem hiding this comment.
Check for null pointers after memory allocation
In lines 63 and 102, the std::malloc calls do not check if the allocation was successful. If malloc returns nullptr, dereferencing the pointer will cause undefined behavior.
Consider adding null pointer checks after malloc and handle the allocation failure appropriately:
+ if (!pages_[i]) {
+ throw std::bad_alloc();
+ }Similarly for line 102.
Also applies to: 102-102
src/net/src/memoey_pool.h
Outdated
| if (bits_.compare_exchange_strong(bit, bit | _bit)) { // Set the i-th bit to 1 | ||
| if (!pages_[i]) { // If the i-th page is not allocated, allocate the i-th page | ||
| pages_[i] = std::malloc(pageSize_ + pageOffset_); | ||
| auto page = reinterpret_cast<uint8_t *>(pages_[i]); | ||
| *page = uint8_t(i); // Set the page head to i | ||
| pages_[i] = ++page; | ||
| } | ||
| return new (pages_[i]) T(std::forward<Args>(args)...); | ||
| } else { | ||
| bit = bits_.load(); | ||
| if (!(bit & _bit)) { | ||
| continue; // If the i-th bit is 0, it means that the i-th page is not used | ||
| } | ||
| } | ||
| } | ||
| ++i; |
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Potential concurrency issues in Allocate method
In the Allocate method (lines 61-76), the manipulation of bits_ using bits_.compare_exchange_strong(bit, bit | _bit) and subsequent operations may lead to race conditions in highly concurrent environments.
Consider revising the synchronization mechanism to ensure thread-safe manipulation of bits_. Using loop constructs and atomic operations carefully can prevent the ABA problem and data races.
src/net/src/memoey_pool.h
Outdated
| bits_ &= ~(1ull << index); | ||
| } |
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Non-atomic modification of bits_ in Deallocate method
In line 97, the operation bits_ &= ~(1ull << index); is not atomic, which can cause data races when Deallocate is called concurrently from multiple threads.
Apply this diff to use an atomic fetch-and operation:
- bits_ &= ~(1ull << index);
+ bits_.fetch_and(~(1ull << index));📝 Committable suggestion
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| bits_ &= ~(1ull << index); | |
| } | |
| bits_.fetch_and(~(1ull << index)); | |
| } |
include/pika_client_conn.h
Outdated
|
|
||
| #include "acl.h" | ||
| #include "include/pika_command.h" | ||
| #include "include/pika_define.h" | ||
| #include "net/src/memoey_pool.h" |
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Correct the include file name
The include directive in line 16 references "net/src/memoey_pool.h", which contains a typo. It should be "net/src/memory_pool.h".
| Cmd* PikaCmdTableManager::GetRawCmd(const std::string& opt) { return GetCmdFromDB(opt, *cmds_); } | ||
|
|
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🛠️ Refactor suggestion
Document ownership semantics for GetRawCmd
The GetRawCmd method needs documentation about ownership and lifetime guarantees.
Consider this implementation:
-Cmd* PikaCmdTableManager::GetRawCmd(const std::string& opt) { return GetCmdFromDB(opt, *cmds_); }
+/**
+ * @brief Gets a raw pointer to a command from the database
+ * @param opt The command name
+ * @return Raw pointer to the command (caller doesn't own the memory)
+ * @note The returned pointer is owned by the command table and remains valid
+ * as long as the command table exists
+ */
+Cmd* PikaCmdTableManager::GetRawCmd(const std::string& opt) {
+ return GetCmdFromDB(opt, *cmds_);
+}📝 Committable suggestion
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| Cmd* PikaCmdTableManager::GetRawCmd(const std::string& opt) { return GetCmdFromDB(opt, *cmds_); } | |
| /** | |
| * @brief Gets a raw pointer to a command from the database | |
| * @param opt The command name | |
| * @return Raw pointer to the command (caller doesn't own the memory) | |
| * @note The returned pointer is owned by the command table and remains valid | |
| * as long as the command table exists | |
| */ | |
| Cmd* PikaCmdTableManager::GetRawCmd(const std::string& opt) { | |
| return GetCmdFromDB(opt, *cmds_); | |
| } |
| Cmd* Clone(net::MemoryPool* pool) override { | ||
| return pool->Allocate<std::remove_pointer<decltype(this)>::type>(*this); | ||
| } |
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🛠️ Refactor suggestion
Add safety checks and documentation for Clone methods
The Clone methods using memory pools need documentation and nullptr checks.
Consider this implementation pattern for all command classes:
- Cmd* Clone(net::MemoryPool* pool) override {
- return pool->Allocate<std::remove_pointer<decltype(this)>::type>(*this);
- }
+ /**
+ * @brief Clones the command using the provided memory pool
+ * @param pool Memory pool to allocate from (must not be nullptr)
+ * @return Raw pointer to the cloned command (owned by the pool)
+ */
+ Cmd* Clone(net::MemoryPool* pool) override {
+ assert(pool != nullptr);
+ return pool->Allocate<std::remove_pointer<decltype(this)>::type>(*this);
+ }Also applies to: 37-39, 74-76, 92-94, 112-114
| @@ -63,7 +63,7 @@ class DispatchThread : public ServerThread { | |||
| DispatchThread(const std::string& ip, int port, int work_num, ConnFactory* conn_factory, int cron_interval, | |||
| int queue_limit, const ServerHandle* handle); | |||
| DispatchThread(const std::set<std::string>& ips, int port, int work_num, ConnFactory* conn_factory, int cron_interval, | |||
| int queue_limit, const ServerHandle* handle); | |||
| int queue_limit, const ServerHandle* handle, size_t memory_pool_page_size); | |||
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💡 Codebase verification
Parameter order mismatch in worker thread initialization
There's a parameter order mismatch in the worker thread initialization:
- WorkerThread constructor expects:
(conn_factory, server_thread, memory_pool_page_size, queue_limit, cron_interval) - But DispatchThread initializes it as:
(conn_factory, this, queue_limit, cron_interval, memory_pool_page_size)
This will cause incorrect parameter assignment and potential memory issues.
src/net/src/dispatch_thread.cc: Fix parameter order inworker_thread_.emplace_back()call to match WorkerThread's constructor signature.
🔗 Analysis chain
Verify thread initialization with memory pool parameter.
The addition of memory_pool_page_size parameter to the constructor is correct, but we should verify its propagation to worker threads.
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rg -A 5 "WorkerThread.*memory_pool"
Length of output: 1374
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#!/bin/bash
# Check the order of parameters in WorkerThread constructor to verify if they match the initialization
ast-grep --pattern 'WorkerThread($$$) {
$$$
}'
Length of output: 50
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#!/bin/bash
# Let's check the implementation details in worker_thread.cc
cat src/net/src/worker_thread.cc
Length of output: 12562
| Cmd* Clone(net::MemoryPool* pool) override { | ||
| return pool->Allocate<std::remove_pointer<decltype(this)>::type>(*this); | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Consider adding virtual destructors for proper cleanup
The command classes implement Clone(net::MemoryPool*) consistently, but since they're part of an inheritance hierarchy (e.g., XRevrangeCmd inherits from XRangeCmd), virtual destructors should be added to ensure proper cleanup of derived classes through base class pointers.
class XRangeCmd : public Cmd {
public:
XRangeCmd(const std::string& name, int arity, uint32_t flag)
: Cmd(name, arity, flag, static_cast<uint32_t>(AclCategory::STREAM)){};
+ virtual ~XRangeCmd() = default;
void Do() override;Also applies to: 59-61, 79-81, 101-103, 119-121, 132-134, 150-152, 169-171
include/pika_command.h
Outdated
| @@ -19,6 +19,7 @@ | |||
| #include "pstd/include/pstd_string.h" | |||
|
|
|||
| #include "net/src/dispatch_thread.h" | |||
| #include "net/src/memoey_pool.h" | |||
There was a problem hiding this comment.
Fix typo in header filename
The memory pool header filename contains a typo: "memoey_pool.h" should be "memory_pool.h"
-#include "net/src/memoey_pool.h"
+#include "net/src/memory_pool.h"📝 Committable suggestion
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| #include "net/src/memoey_pool.h" | |
| #include "net/src/memory_pool.h" |
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Actionable comments posted: 6
🧹 Nitpick comments (1)
src/net/src/memory_pool.h (1)
29-34: Unnecessary initialization ofpages_arrayThe
pages_array is default-initialized, and the explicit loop setting elements tonullptrmay be redundant.Consider initializing
pages_using aggregate initialization for clarity and efficiency:std::array<void*, 64> pages_ = {};This approach zero-initializes all elements in the array.
📜 Review details
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Review profile: CHILL
Plan: Pro
📒 Files selected for processing (5)
include/pika_client_conn.h(3 hunks)include/pika_command.h(2 hunks)src/net/include/net_conn.h(2 hunks)src/net/src/memory_pool.h(1 hunks)src/net/src/worker_thread.h(3 hunks)
🚧 Files skipped from review as they are similar to previous changes (3)
- src/net/include/net_conn.h
- include/pika_command.h
- src/net/src/worker_thread.h
🔇 Additional comments (1)
include/pika_client_conn.h (1)
136-136: Consider unifying command pointer handling for simplicity
The DoCmd method now returns std::variant<std::shared_ptr<Cmd>, Cmd*>, which increases complexity in command handling. Managing both smart pointers and raw pointers can lead to confusion and potential errors.
src/net/src/memory_pool.h
Outdated
| auto page = reinterpret_cast<uint8_t *>(ptr) - 1; | ||
| ptr->~T(); | ||
|
|
||
| if (*page == extendFlag_) { // If the page head is 0xFF, it means that the page is extra | ||
| std::free(page); | ||
| return; | ||
| } | ||
|
|
||
| auto index = *page; | ||
| bits_ &= ~(1ull << index); | ||
| } |
There was a problem hiding this comment.
Undefined behavior due to pointer arithmetic
In the Deallocate method, the code performs pointer arithmetic to access memory before the allocated object:
auto page = reinterpret_cast<uint8_t *>(ptr) - 1;Accessing memory before the allocated object leads to undefined behavior according to the C++ standard. This can cause issues with memory safety and alignment.
Consider redesigning the memory layout to avoid accessing memory outside the bounds of the allocated object. One approach is to allocate additional space after the object for metadata or use a separate data structure to track allocations.
| if (bits_.compare_exchange_strong(bit, bit | _bit)) { // Set the i-th bit to 1 | ||
| if (!pages_[i]) { // If the i-th page is not allocated, allocate the i-th page | ||
| pages_[i] = std::malloc(pageSize_ + pageOffset_); | ||
| auto page = reinterpret_cast<uint8_t *>(pages_[i]); | ||
| *page = uint8_t(i); // Set the page head to i | ||
| pages_[i] = ++page; | ||
| } | ||
| return new (pages_[i]) T(std::forward<Args>(args)...); | ||
| } else { | ||
| bit = bits_.load(); | ||
| if (!(bit & _bit)) { | ||
| continue; // If the i-th bit is 0, it means that the i-th page is not used |
There was a problem hiding this comment.
Race conditions when accessing pages_ array
In the Allocate method, multiple threads may concurrently access and modify pages_[i] without proper synchronization. This can lead to race conditions during page allocation and initialization.
Ensure thread-safe access to pages_[i] by introducing synchronization mechanisms. You can use a mutex or atomic pointer operations to protect the initialization and assignment of pages_[i].
For example:
if (!pages_[i]) { // If the i-th page is not allocated, allocate the i-th page
+ std::lock_guard<std::mutex> lock(pages_mutex_);
if (!pages_[i]) { // Double-checked locking
pages_[i] = std::malloc(pageSize_ + pageOffset_);
// Initialize the page
}
}Also, declare a mutex for synchronizing access:
std::mutex pages_mutex_;| *page = extendFlag_; // Set the page head to 0xFF | ||
| return new (++page) T(std::forward<Args>(args)...); |
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Potential alignment issues with incremented pointers
In AllocateExtend, the code increments the pointer after allocation:
auto page = reinterpret_cast<uint8_t *>(newPage);
*page = extendFlag_; // Set the page head to 0xFF
return new (++page) T(std::forward<Args>(args)...);Incrementing the pointer may result in misaligned memory addresses, leading to undefined behavior on platforms that require alignment.
Ensure the allocated memory is properly aligned for type T. You can use std::align to adjust the pointer or allocate memory using std::aligned_alloc (C++17) to guarantee the correct alignment.
For example:
void* newPage = std::aligned_alloc(alignof(T), sizeof(T) + pageOffset_);Also, adjust the code to avoid incrementing pointers in a way that may misalign them.
src/net/src/memory_pool.h
Outdated
| auto page = reinterpret_cast<uint8_t *>(ptr) - 1; | ||
| ptr->~T(); | ||
|
|
||
| if (*page == extendFlag_) { // If the page head is 0xFF, it means that the page is extra | ||
| std::free(page); | ||
| return; | ||
| } | ||
|
|
||
| auto index = *page; | ||
| bits_ &= ~(1ull << index); |
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Potential thread safety issue in Deallocate method
The operation bits_ &= ~(1ull << index); in the Deallocate method is not atomic. This read-modify-write operation on an std::atomic<uint64_t> can lead to race conditions in multithreaded environments when multiple threads deallocate memory concurrently.
Consider using an atomic fetch-and operation to ensure thread safety. You can modify the code as follows:
- bits_ &= ~(1ull << index);
+ bits_.fetch_and(~(1ull << index));📝 Committable suggestion
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Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| auto page = reinterpret_cast<uint8_t *>(ptr) - 1; | |
| ptr->~T(); | |
| if (*page == extendFlag_) { // If the page head is 0xFF, it means that the page is extra | |
| std::free(page); | |
| return; | |
| } | |
| auto index = *page; | |
| bits_ &= ~(1ull << index); | |
| auto page = reinterpret_cast<uint8_t *>(ptr) - 1; | |
| ptr->~T(); | |
| if (*page == extendFlag_) { // If the page head is 0xFF, it means that the page is extra | |
| std::free(page); | |
| return; | |
| } | |
| auto index = *page; | |
| bits_.fetch_and(~(1ull << index)); |
include/pika_client_conn.h
Outdated
| @@ -127,7 +131,9 @@ class PikaClientConn : public net::RedisConn { | |||
| bool authenticated_ = false; | |||
| std::shared_ptr<User> user_; | |||
|
|
|||
| std::shared_ptr<Cmd> DoCmd(const PikaCmdArgsType& argv, const std::string& opt, | |||
| net::MemoryPool *memory_pool_; | |||
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Uninitialized member memory_pool_
The member variable memory_pool_ is a raw pointer and may not be initialized upon object creation. Using it without initialization can lead to undefined behavior.
Initialize memory_pool_ to nullptr in the constructor or at the point of declaration:
- net::MemoryPool *memory_pool_;
+ net::MemoryPool *memory_pool_ = nullptr;This ensures that the pointer has a known state before it is assigned a valid memory pool.
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| net::MemoryPool *memory_pool_; | |
| net::MemoryPool *memory_pool_ = nullptr; |
include/pika_client_conn.h
Outdated
| @@ -114,6 +116,8 @@ | |||
|
|
|||
| std::shared_ptr<TimeStat> time_stat_; | |||
|
|
|||
| void SetMemoryPool(net::MemoryPool *memory_pool) override{ memory_pool_ = memory_pool; } | |||
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Incorrect use of override specifier
The method SetMemoryPool is marked with override, but it's unclear if net::RedisConn (the base class) declares a virtual method with the same signature. If not, this will cause a compilation error.
Verify whether the base class net::RedisConn has a virtual method SetMemoryPool(net::MemoryPool*). If it does not, you should remove the override specifier:
- void SetMemoryPool(net::MemoryPool *memory_pool) override { memory_pool_ = memory_pool; }
+ void SetMemoryPool(net::MemoryPool *memory_pool) { memory_pool_ = memory_pool; }Alternatively, if the intention is to override a method, ensure that the base class declares it appropriately.
Committable suggestion skipped: line range outside the PR's diff.
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Actionable comments posted: 1
♻️ Duplicate comments (4)
src/net/src/memory_pool.h (4)
41-48:⚠️ Potential issueFix unsafe pointer arithmetic in destructor
The destructor performs unsafe pointer arithmetic by decrementing the pointer before freeing:
auto ptr = reinterpret_cast<uint8_t *>(pages_[i]); std::free(--ptr);Consider redesigning the memory layout to avoid accessing memory before the allocated object. One approach:
~MemoryPool() { for (int i = 0; i < 64; i++) { if (pages_[i] != nullptr) { - auto ptr = reinterpret_cast<uint8_t *>(pages_[i]); - std::free(--ptr); + // Store the original allocation pointer + auto ptr = reinterpret_cast<uint8_t *>(pages_[i]) - pageOffset_; + std::free(ptr); } } }
61-67:⚠️ Potential issueFix race condition in page initialization
The page initialization lacks proper synchronization, which could lead to race conditions.
Add proper synchronization:
+ std::mutex pages_mutex_; // Add as class member if (!pages_[i]) { + std::lock_guard<std::mutex> lock(pages_mutex_); if (!pages_[i]) { // Double-checked locking pages_[i] = std::malloc(pageSize_ + pageOffset_); auto page = reinterpret_cast<uint8_t *>(pages_[i]); *page = uint8_t(i); pages_[i] = ++page; } }
85-89:⚠️ Potential issueFix unsafe memory access in Deallocate
The code performs unsafe pointer arithmetic to access memory before the allocated object:
auto page = reinterpret_cast<uint8_t *>(ptr) - 1;Consider redesigning the memory layout to store metadata safely:
template <typename T> void Deallocate(T *ptr) { - auto page = reinterpret_cast<uint8_t *>(ptr) - 1; + // Access metadata through a safe offset from the base allocation + auto base = reinterpret_cast<uint8_t *>(ptr) - pageOffset_; + auto page = base; ptr->~T();
100-106:⚠️ Potential issueEnsure proper alignment after pointer arithmetic
The pointer increment after setting the page head could affect alignment:
*page = extendFlag_; // Set the page head to 0xFF return new (++page) T(std::forward<Args>(args)...);Consider maintaining alignment when adjusting the pointer:
template <typename T, typename... Args> T *AllocateExtend(Args &&...args) { - auto newPage = std::aligned_alloc(alignof(T), sizeof(T) + pageOffset_); - auto page = reinterpret_cast<uint8_t *>(newPage); - *page = extendFlag_; // Set the page head to 0xFF - return new (++page) T(std::forward<Args>(args)...); + // Calculate total size needed with proper padding for alignment + size_t totalSize = sizeof(T) + pageOffset_; + totalSize = (totalSize + alignof(T) - 1) & ~(alignof(T) - 1); + + auto newPage = std::aligned_alloc(alignof(T), totalSize); + auto base = reinterpret_cast<uint8_t *>(newPage); + *base = extendFlag_; + + // Ensure the object portion is properly aligned + auto objPtr = reinterpret_cast<void *>(base + pageOffset_); + return new (objPtr) T(std::forward<Args>(args)...); }
🧹 Nitpick comments (2)
src/net/src/memory_pool.h (2)
55-57: Clarify the performance optimization commentThe comment suggests moving
bits_.load()into the loop but doesn't explain why or what race conditions it addresses.Consider improving the comment to explain the tradeoff:
- // If you are in a particularly high multithreaded race scenario - // you can put bits_.load() into the for loop + // NOTE: In high-contention scenarios, moving bits_.load() inside the loop + // can reduce ABA problems at the cost of additional atomic operations
14-24: Consider enhancing the memory pool architectureThe current design could benefit from several architectural improvements:
Memory Efficiency:
- Consider implementing variable-sized pages to reduce internal fragmentation
- Add support for different allocation strategies based on object sizes
Monitoring & Debugging:
- Add statistics tracking (allocation count, page utilization, etc.)
- Include debug assertions and logging for memory corruption detection
Resource Management:
- Implement memory pressure handling
- Add support for pool resizing based on demand
Would you like help implementing any of these architectural improvements?
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📒 Files selected for processing (2)
include/pika_client_conn.h(3 hunks)src/net/src/memory_pool.h(1 hunks)
🚧 Files skipped from review as they are similar to previous changes (1)
- include/pika_client_conn.h
| class MemoryPool { | ||
| public: | ||
| explicit MemoryPool() : MemoryPool(512) {} | ||
| explicit MemoryPool(int64_t pageSize) : pageSize_(pageSize) { | ||
| for (int i = 0; i < 64; i++) { | ||
| pages_[i] = nullptr; | ||
| } | ||
| } | ||
|
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||
| MemoryPool(const MemoryPool &) = delete; | ||
| MemoryPool &operator=(const MemoryPool &) = delete; | ||
| MemoryPool(MemoryPool &&) = delete; | ||
| MemoryPool &operator=(MemoryPool &&) = delete; | ||
|
|
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🛠️ Refactor suggestion
Consider improving scalability and adding validation
The current implementation has several limitations:
- The fixed size array of 64 pages limits scalability
- There's no validation for
pageSize_parameter - The page limit of 64 is not documented in the class description
Consider these improvements:
- Use a dynamic container (e.g.,
std::vector) with mutex protection forpages_ - Add validation in the constructor:
explicit MemoryPool(int64_t pageSize) : pageSize_(pageSize) {
+ if (pageSize <= 0) {
+ throw std::invalid_argument("Page size must be positive");
+ }
for (int i = 0; i < 64; i++) {- Add documentation about the 64-page limit in the class description
Also applies to: 108-114
void func1() {
MemoryPool pool;
std::vector<C *> vector;
vector.reserve(20);
for (int i = 0; i < 1000000; ++i) {
vector.clear();
for (int j = 0; j < 20; ++j) {
C *c = pool.Allocate<C>();
vector.emplace_back(c);
}
for (const auto &item: vector) {
pool.Deallocate(item);
}
}
}
void func2() {
std::vector<C *> vector;
vector.reserve(20);
for (int i = 0; i < 1000000; ++i) {
vector.clear();
for (int j = 0; j < 20; ++j) {
C *c = new C();
vector.emplace_back(c);
}
for (const auto &item: vector) {
delete item;
}
}
}
int main() {
auto start = std::chrono::high_resolution_clock::now();
func1();
auto end = std::chrono::high_resolution_clock::now();
std::chrono::duration<double, std::milli> elapsed = end - start;
std::cout << "Function1 took ms:" << elapsed.count() << " s:" << elapsed.count() / 1000.0f << std::endl;
start = std::chrono::high_resolution_clock::now();
func2();
end = std::chrono::high_resolution_clock::now();
elapsed = end - start;
std::cout << "Function2 took ms:" << elapsed.count() << " s:" << elapsed.count() / 1000.0f << std::endl;
return 0;
}
用这个例子测试下来, 性能提升还是非常明显的 |
优化命令对象, 使用内存池管理命令对象 避免每次执行命令都需要复制一个命令,
Summary by CodeRabbit
New Features
MemoryPoolclass for efficient memory management.Clonemethods across various command classes to utilize the memory pool for object allocation.PikaCmdTableManagerfor retrieving raw commands and calculating maximum command size.Bug Fixes
Documentation
Chores