memory_pool_collection fails to allocate memory about memory HOT 4 CLOSED

I've changed memory_pool_collection to use the current block size instead, which should also solve the problem.

from memory.

It seems like the fixed block allocator does not work with memory pool collection - when I changed it to the growing block allocator all seems to work fine. I'd think that there shouldn't be a reason for the fixed allocator not to work in this case, am I wrong?
Anyway, I continue to look into this because I do need a fixed allocator and I do need several node sizes. Will be happy if anyone can still help.
Thanks.

from memory.

so the issue is that the memory pool collection always looks at the next block size when assigning memory to a bucket (free list) which will not work with fixed buffer as fixed buffer allocates the block in the creation of the object and then next block will always be 0.

@foonathan is this an intended behavior or a bug?
Thanks.

from memory.

In the meantime I wrote a wrppar class to the fixed allocator that returns the allocated block_size in next_block_size (instead of zero) and it seems to work fine.

template<class RawAllocator = memory::default_allocator>
    class fixed_block_allocator_for_memory_pool_collection {

    public:
        using allocator_type = memory::traits_detail::allocator_type<RawAllocator>;
        explicit fixed_block_allocator_for_memory_pool_collection(std::size_t block_size) noexcept
                                                                  : _underline_allocator(block_size, allocator_type()), _block_size(block_size) {}

        memory::memory_block allocate_block() {
            return _underline_allocator.allocate_block();
        }

        void deallocate_block(memory::memory_block block) noexcept {
            _underline_allocator.deallocate_block(block);
        }
        
        allocator_type& get_allocator() noexcept
        {
            return _underline_allocator.get_allocator();
        }

        std::size_t next_block_size() const noexcept {
            return _block_size;
        }

    private:
        size_t                                          _block_size;
        memory::fixed_block_allocator<RawAllocator>     _underline_allocator;
    };

Please let me know if this is something that you would like me to upload as a PR.

from memory.