Reader-writer (RW) MCS lock classes. More...

Detailed Description

Reader-writer (RW) MCS lock classes.

These are mainly used for record locks.Pre-allocated MCS block for simpler version of RW-locks.

Definition at line 387 of file xct_id.hpp.

#include <xct_id.hpp>

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Classes
union	Self

Public Member Functions
void	init_reader ()

void	init_writer ()

void	init_common () __attribute__((always_inline))

bool	is_reader () __attribute__((always_inline))

uint8_t	read_state ()

void	unblock () __attribute__((always_inline))

bool	is_blocked () __attribute__((always_inline))

bool	is_granted ()

void	set_finalized ()

bool	is_finalized ()

bool	timeout_granted (int32_t timeout)
	MCS block classes. More...

void	set_successor_class_writer ()

void	set_successor_next_only (thread::ThreadId thread_id, McsBlockIndex block_index)

bool	has_successor ()

bool	successor_is_ready ()

bool	has_reader_successor ()

bool	has_writer_successor ()

uint16_t	make_blocked_with_reader_successor_state ()

uint16_t	make_blocked_with_no_successor_state ()

Public Attributes
union foedus::xct::McsRwSimpleBlock::Self	self_

thread::ThreadId	successor_thread_id_

McsBlockIndex	successor_block_index_

Static Public Attributes
static const uint8_t	kStateClassMask = 3U

static const uint8_t	kStateClassReaderFlag = 1U

static const uint8_t	kStateClassWriterFlag = 2U

static const uint8_t	kStateBlockedFlag = 1U << 7U

static const uint8_t	kStateBlockedMask = 1U << 7U

static const uint8_t	kStateFinalizedMask = 4U

static const uint8_t	kSuccessorClassReader = 1U

static const uint8_t	kSuccessorClassWriter = 2U

static const uint8_t	kSuccessorClassNone = 3U

static const int32_t	kTimeoutNever = 0xFFFFFFFF

Class Documentation

union foedus::xct::McsRwSimpleBlock::Self

Definition at line 403 of file xct_id.hpp.

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Class Members
struct Components	components_
uint16_t	data_

Member Function Documentation

bool foedus::xct::McsRwSimpleBlock::has_reader_successor ( )

inline

Definition at line 492 of file xct_id.hpp.

References foedus::xct::McsRwSimpleBlock::Self::components_, kSuccessorClassReader, self_, and foedus::xct::McsRwSimpleBlock::Self::Components::successor_class_.

                                      {
     uint8_t s = assorted::atomic_load_acquire<uint8_t>(&self_.components_.successor_class_);
     return s == kSuccessorClassReader;
   }

bool foedus::xct::McsRwSimpleBlock::has_successor ( )

inline

Definition at line 484 of file xct_id.hpp.

References foedus::xct::McsRwSimpleBlock::Self::components_, self_, and foedus::xct::McsRwSimpleBlock::Self::Components::successor_class_.

                               {
     return assorted::atomic_load_acquire<uint8_t>(
       &self_.components_.successor_class_) != kSuccessorClassNone;
   }

bool foedus::xct::McsRwSimpleBlock::has_writer_successor ( )

inline

Definition at line 496 of file xct_id.hpp.

References foedus::xct::McsRwSimpleBlock::Self::components_, kSuccessorClassWriter, self_, and foedus::xct::McsRwSimpleBlock::Self::Components::successor_class_.

                                      {
     uint8_t s = assorted::atomic_load_acquire<uint8_t>(&self_.components_.successor_class_);
     return s == kSuccessorClassWriter;
   }

void foedus::xct::McsRwSimpleBlock::init_common ( )

inline

Definition at line 428 of file xct_id.hpp.

References foedus::xct::McsRwSimpleBlock::Self::components_, kSuccessorClassNone, foedus::assorted::memory_fence_release(), self_, and foedus::xct::McsRwSimpleBlock::Self::Components::successor_class_.

Referenced by init_reader(), and init_writer().

                                           {
     self_.components_.successor_class_ = kSuccessorClassNone;
     successor_thread_id_ = 0;
     successor_block_index_ = 0;
     assorted::memory_fence_release();
   }

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void foedus::xct::McsRwSimpleBlock::init_reader ( )

inline

Definition at line 420 of file xct_id.hpp.

References foedus::xct::McsRwSimpleBlock::Self::components_, init_common(), kStateBlockedFlag, self_, and foedus::xct::McsRwSimpleBlock::Self::Components::state_.

                             {
     self_.components_.state_ = kStateClassReaderFlag | kStateBlockedFlag;
     init_common();
   }

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void foedus::xct::McsRwSimpleBlock::init_writer ( )

inline

Definition at line 424 of file xct_id.hpp.

References foedus::xct::McsRwSimpleBlock::Self::components_, init_common(), kStateBlockedFlag, self_, and foedus::xct::McsRwSimpleBlock::Self::Components::state_.

                             {
     self_.components_.state_ = kStateClassWriterFlag | kStateBlockedFlag;
     init_common();
   }

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bool foedus::xct::McsRwSimpleBlock::is_blocked ( )

inline

Definition at line 447 of file xct_id.hpp.

References kStateBlockedMask, and read_state().

Referenced by is_granted(), and foedus::xct::McsImpl< ADAPTOR, McsRwSimpleBlock >::release_rw_reader().

                                          {
     return read_state() & kStateBlockedMask;
   }

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bool foedus::xct::McsRwSimpleBlock::is_finalized ( )

inline

Definition at line 460 of file xct_id.hpp.

References ASSERT_ND, is_reader(), kStateFinalizedMask, and read_state().

Referenced by set_finalized().

                              {
     ASSERT_ND(is_reader());
     return read_state() & kStateFinalizedMask;
   }

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bool foedus::xct::McsRwSimpleBlock::is_granted ( )

inline

Definition at line 450 of file xct_id.hpp.

References is_blocked().

Referenced by timeout_granted().

                            {
     return !is_blocked();
   }

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bool foedus::xct::McsRwSimpleBlock::is_reader ( )

inline

Definition at line 435 of file xct_id.hpp.

References foedus::xct::McsRwSimpleBlock::Self::components_, kStateClassReaderFlag, self_, and foedus::xct::McsRwSimpleBlock::Self::Components::state_.

Referenced by is_finalized(), foedus::xct::McsImpl< ADAPTOR, McsRwSimpleBlock >::release_rw_reader(), and set_finalized().

                                         {
     return (self_.components_.state_ & kStateClassMask) == kStateClassReaderFlag;
   }

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uint16_t foedus::xct::McsRwSimpleBlock::make_blocked_with_no_successor_state ( )

inline

Definition at line 506 of file xct_id.hpp.

References foedus::xct::McsRwSimpleBlock::Self::components_, kStateBlockedFlag, kSuccessorClassNone, self_, and foedus::xct::McsRwSimpleBlock::Self::Components::state_.

                                                   {
     uint8_t state = self_.components_.state_ | kStateBlockedFlag;
     return (uint16_t)state << 8 | kSuccessorClassNone;
   }

uint16_t foedus::xct::McsRwSimpleBlock::make_blocked_with_reader_successor_state ( )

inline

Definition at line 501 of file xct_id.hpp.

References foedus::xct::McsRwSimpleBlock::Self::components_, kStateBlockedFlag, kSuccessorClassReader, self_, and foedus::xct::McsRwSimpleBlock::Self::Components::state_.

                                                       {
     // Only using the class bit, which doesn't change, so no need to use atomic ops.
     uint8_t state = self_.components_.state_ | kStateBlockedFlag;
     return (uint16_t)state << 8 | kSuccessorClassReader;
   }

uint8_t foedus::xct::McsRwSimpleBlock::read_state ( )

inline

Definition at line 438 of file xct_id.hpp.

References foedus::xct::McsRwSimpleBlock::Self::components_, self_, and foedus::xct::McsRwSimpleBlock::Self::Components::state_.

Referenced by is_blocked(), is_finalized(), and unblock().

                               {
     return assorted::atomic_load_acquire<uint8_t>(&self_.components_.state_);
   }

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void foedus::xct::McsRwSimpleBlock::set_finalized ( )

inline

Definition at line 453 of file xct_id.hpp.

References ASSERT_ND, foedus::xct::McsRwSimpleBlock::Self::components_, is_finalized(), is_reader(), kStateFinalizedMask, self_, and foedus::xct::McsRwSimpleBlock::Self::Components::state_.

                               {
     ASSERT_ND(is_reader());
     ASSERT_ND(!is_finalized());
     assorted::raw_atomic_fetch_and_bitwise_or<uint8_t>(
       &self_.components_.state_, kStateFinalizedMask);
     ASSERT_ND(is_finalized());
   }

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void foedus::xct::McsRwSimpleBlock::set_successor_class_writer ( )

inline

Definition at line 465 of file xct_id.hpp.

References ASSERT_ND, foedus::xct::McsRwSimpleBlock::Self::components_, kSuccessorClassWriter, self_, and foedus::xct::McsRwSimpleBlock::Self::Components::successor_class_.

                                            {
     // In case the caller is a reader appending after a writer or waiting reader,
     // the requester should have already set the successor class to "reader" through by CASing
     // self_.data_ from [no-successor, blocked] to [reader successor, blocked].
     ASSERT_ND(self_.components_.successor_class_ == kSuccessorClassNone);
     assorted::raw_atomic_fetch_and_bitwise_and<uint8_t>(
       &self_.components_.successor_class_, kSuccessorClassWriter);
   }

void foedus::xct::McsRwSimpleBlock::set_successor_next_only	(	thread::ThreadId	thread_id,
		McsBlockIndex	block_index
	)

inline

Definition at line 473 of file xct_id.hpp.

References ASSERT_ND, foedus::xct::McsRwSimpleBlock::Self::data_, self_, successor_block_index_, and successor_thread_id_.

                                                                                            {
     McsRwSimpleBlock tmp;
     tmp.self_.data_ = 0;
     tmp.successor_thread_id_ = thread_id;
     tmp.successor_block_index_ = block_index;
     ASSERT_ND(successor_thread_id_ == 0);
     ASSERT_ND(successor_block_index_ == 0);
     uint64_t *address = reinterpret_cast<uint64_t*>(this);
     uint64_t mask = *reinterpret_cast<uint64_t*>(&tmp);
     assorted::raw_atomic_fetch_and_bitwise_or<uint64_t>(address, mask);
   }

bool foedus::xct::McsRwSimpleBlock::successor_is_ready ( )

inline

Definition at line 488 of file xct_id.hpp.

References successor_block_index_.

                                    {
     // Check block index only - thread ID could be 0
     return assorted::atomic_load_acquire<McsBlockIndex>(&successor_block_index_) != 0;
   }

bool foedus::xct::McsRwSimpleBlock::timeout_granted ( int32_t timeout )

MCS block classes.

Definition at line 133 of file xct_id.cpp.

References is_granted(), kTimeoutNever, foedus::assorted::spin_until(), and foedus::assorted::yield_if_valgrind().

                                                       {
   if (timeout == kTimeoutNever) {
     assorted::spin_until([this]{ return this->is_granted(); });
     return true;
   } else {
     while (--timeout) {
       if (is_granted()) {
         return true;
       }
       assorted::yield_if_valgrind();
     }
     return is_granted();
   }
 }

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void foedus::xct::McsRwSimpleBlock::unblock ( )

inline

Definition at line 441 of file xct_id.hpp.

References ASSERT_ND, foedus::xct::McsRwSimpleBlock::Self::components_, read_state(), self_, and foedus::xct::McsRwSimpleBlock::Self::Components::state_.

Referenced by foedus::xct::McsImpl< ADAPTOR, McsRwSimpleBlock >::release_rw_reader().

                                       {
     ASSERT_ND(read_state() & kStateBlockedFlag);
     assorted::raw_atomic_fetch_and_bitwise_and<uint8_t>(
       &self_.components_.state_,
       static_cast<uint8_t>(~kStateBlockedMask));
   }