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The slab pointer goes into a cookie.

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This commit is contained in:
ADAM David Alan Martin
2024-05-13 15:23:28 -04:00
parent af9124ee34
commit d783d15a38
2 changed files with 46 additions and 47 deletions
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80
Memory/ThreadSlab.h
View File

@ -26,34 +26,15 @@ namespace Alepha::Hydrogen::Memory ::detail:: ThreadSlab_m
template< typename T >
class exports::ThreadSlab
{
private:
public:
inline static thread_local Blob slab;
using Slot= std::tuple< void *, Blob::StorageReservation >;
std::array< Slot, 16 > slots;
void
dumpSlots() const
{
std::cerr << "Slot map for " << (void *) this << std::endl;
for( const auto &[ key, res ]: slots )
{
std::cerr << (void *) key << " -> " << (void *) res.get() << std::endl;
}
}
std::size_t
freeSlots() const
{
return std::count( begin( slots ), end( slots ), Slot{ nullptr, nullptr } );
}
public:
using value_type= T;
using propagate_on_container_copy_assignment= std::true_type;
using propagate_on_container_move_assignment= std::true_type;
using propagate_on_container_swap= std::true_type;
using is_always_equal= std::false_type;
using is_always_equal= std::true_type;
ThreadSlab select_on_container_copy_construction() { auto rv= ThreadSlab{}; }
@ -66,48 +47,53 @@ namespace Alepha::Hydrogen::Memory ::detail:: ThreadSlab_m
ThreadSlab( ThreadSlab &&other ) : ThreadSlab( std::as_const( other ) ) {}
~ThreadSlab()
{
std::cerr << "Reporting " << slab.reservation().use_count() << " living allocations when "
<< (void *) this << " is retired." << std::endl;
}
[[nodiscard]] T *
allocate( const std::size_t amt )
{
std::cerr << "Pre allocation there are " << freeSlots() << " free slots" << std::endl;
dumpSlots();
if( slab.size() < amt ) slab.reset( std::max( amt, C::slabSize ) );
// TODO: Alignment?
const std::size_t req= amt + sizeof( Blob::StorageReservation );
if( slab.size() < req ) slab.reset( std::max( req, C::slabSize ) );
const auto slot= std::find( begin( slots ), end( slots ), Slot{ nullptr, nullptr } );
assert( slot != end( slots ) );
std::cerr << "Reporting " << slab.reservation().use_count() << " living allocations when "
<< (void *) this << " made an allocation." << std::endl;
auto next= slab.carveHead( amt );
const auto rv= &next.template as< T >();
*slot= { rv, next.reservation() };
std::cerr << "Allocated: " << (void *) rv << std::endl;
auto next= slab.carveHead( req );
new ( &next.template as< Blob::StorageReservation >() ) Blob::StorageReservation{ next.reservation() };
const auto rv= reinterpret_cast< T * >( &next.template as< Blob::StorageReservation >() + 1 );
next.reset();
std::cerr << "Post allocation there are " << freeSlots() << " free slots" << std::endl;
dumpSlots();
std::cerr << "Reporting " << slab.reservation().use_count() << " living allocations when "
<< (void *) this << " made an allocation." << std::endl;
return rv;
}
template< typename SP >
static void
destroy( SP *p )
{
p->~SP();
}
void
deallocate( T *const p, const std::size_t /* ignored */ ) noexcept
{
std::cerr << "Pre deallocation there are " << freeSlots() << " free slots" << std::endl;
dumpSlots();
const auto slot= std::find_if( begin( slots ), end( slots ),
[p]( const auto &slot ){ const auto &[ which, _ ]= slot; return which == p; } );
assert( slot != end( slots ) );
std::cerr << "Reporting " << slab.reservation().use_count() << " living allocations when "
<< (void *) this << " made a deallocation." << std::endl;
auto *const hidden= reinterpret_cast< Blob::StorageReservation * >( p ) - 1;
destroy( hidden );
*slot= { nullptr, nullptr };
std::cerr << "Deallocated: " << (void *) p << std::endl;
std::cerr << "Post deallocation there are " << freeSlots() << " free slots" << std::endl;
dumpSlots();
std::cerr << "Reporting " << slab.reservation().use_count() << " living allocations when "
<< (void *) this << " made a deallocation." << std::endl;
}
friend constexpr bool
operator == ( const ThreadSlab &a, const ThreadSlab &b ) noexcept
{
return a.slots == b.slots;
}
friend constexpr bool operator == ( const ThreadSlab &, const ThreadSlab & ) noexcept { return true; }
};
}

13
Memory/ThreadSlab.test/0.cc
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@ -13,6 +13,13 @@ static auto init= Alepha::Utility::enroll <=[]
using namespace Alepha::Memory::exports::ThreadSlab_m;
using String= ThreadSlabString;
"Check slab usage"_test <=[]
{
std::cout << "I see " << Alepha::Memory::ThreadSlab< char >::slab.reservation().use_count() << " reservations in a separate test." <<
std::endl;
};
"Can we work with simple `ThreadSlabStrings` without errors?"_test <=[]
{
String s;
@ -33,4 +40,10 @@ static auto init= Alepha::Utility::enroll <=[]
std::cout << s3 << std::endl;
};
"Check slab usage"_test <=[]
{
std::cout << "I see " << Alepha::Memory::ThreadSlab< char >::slab.reservation().use_count() << " reservations in a separate test." <<
std::endl;
};
};