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

[Jinoh Kang (＠iamahuman)]

Jinoh Kang (@iamahuman) commented about dlls/ntdll/heap.c:
> +static struct block *find_free_bin_block( struct heap *heap, ULONG flags, SIZE_T block_size, struct bin *bin )
> +{
> - ULONG affinity = heap_current_thread_affinity();
> - struct block *block;
> - struct group *group;
> -
> - /* acquire a group, the thread will own it and no other thread can clear free bits.
> -
> * some other thread might still set the free bits if they are freeing blocks.
> -
> */
> - if (!(group = heap_acquire_bin_group( heap, flags, block_size, bin ))) return NULL;
> - group->affinity = affinity;
> -
> - /* serialize with heap_free_block_lfh: atomically set GROUP_FLAG_FREE when the free bits are all 0. */
> - if (group_find_free_block( group, block_size, &block ))
> -
>    InterlockedAnd( &group->free_bits, ~GROUP_FLAG_FREE );
> - else

Here's my hopefully final suggestion, which enhances both performance (less Interlocked ops) and verifiability without harming readability: how about ensuring that all groups in list or affinity array have `GROUP_FLAG_FREE` unset?  This way, we don't need two `InterlockedAnd` ops for the _partially free_ case.

Patches linked to this suggestion is annotated with `[free-unset-v7]`.

```suggestion:-2+0
    if (!group_find_free_block( group, block_size, &block ))
```