Re: [RFC 2/4] blkdev: lift BLK_MAX_BLOCK_SIZE to page cache limit

[Bart Van Assche <bvanassche@xxxxxxx>]

On 3/20/25 4:13 AM, Luis Chamberlain wrote:
> -/*
> - * We should strive for 1 << (PAGE_SHIFT + MAX_PAGECACHE_ORDER)
> - * however we constrain this to what we can validate and test.
> - */
> -#define BLK_MAX_BLOCK_SIZE      SZ_64K
> +#define BLK_MAX_BLOCK_SIZE      1 << (PAGE_SHIFT + MAX_PAGECACHE_ORDER)
>   
>   /* blk_validate_limits() validates bsize, so drivers don't usually need to */
>   static inline int blk_validate_block_size(unsigned long bsize)

All logical block sizes above 4 KiB trigger write amplification if there
are applications that write 4 KiB at a time, isn't it? Isn't that issue
even worse for logical block sizes above 64 KiB?

Thanks,

Bart.