Re: [PATCH v7 0/8] MR1628: ntdll: Implement Low Fragmentation Heap.

[Jinoh Kang (＠iamahuman)]

Jinoh Kang (@iamahuman) commented about dlls/ntdll/heap.c:
> +}
> -
>
> +static inline struct block *group_get_block( struct group *group, SIZE_T block_size, UINT index )
> +{
> - char *first_block = (char *)&group->first_block;
> - return (struct block *)(first_block + index * block_size);
>
> +}
> -
>
> +/* lookup a free block using the group free_bits, the current thread must own the group */
> +static inline LONG group_find_free_block( struct group *group, SIZE_T block_size, struct block **block )
> +{
> - ULONG i, free_bits = ReadNoFence( &group->free_bits );
> - /* free_bits & ~GROUP_FLAG_FREE will never be 0 as the group is unlinked when it's fully used */
> - BitScanForward( &i, free_bits & ~GROUP_FLAG_FREE );
> - *block = group_get_block( group, block_size, i );
> - return InterlockedAnd( &group->free_bits, ~(1 << i) ) & ~(1 << i);

Try not to use `InterlockedAnd`'s return value if you don't want it to transform to cmpxchg loop.