svn commit: r356480 - head/sys/dev/nvme

[Konstantin Belousov]

On Tue, Jan 07, 2020 at 11:10:39PM +0000, Alexander Motin wrote:
> Author: mav
> Date: Tue Jan  7 23:10:38 2020
> New Revision: 356480
> URL: https://svnweb.freebsd.org/changeset/base/356480
> 
> Log:
>   Increate HMB limit from 1% to 5%.
>   
>   SSD capacity in laptops is growing faster then RAM size, so my original
>   guess seems too low on second thought.  Hopefully nobody will build large
>   array of those crappy SSDs.
It seems that this should be a knob.

>   
>   MFC after:	2 weeks
>   X-MFC-with:	356474
> 
> Modified:
>   head/sys/dev/nvme/nvme_ctrlr.c
> 
> Modified: head/sys/dev/nvme/nvme_ctrlr.c
> ==============================================================================
> --- head/sys/dev/nvme/nvme_ctrlr.c	Tue Jan  7 22:45:02 2020	(r356479)
> +++ head/sys/dev/nvme/nvme_ctrlr.c	Tue Jan  7 23:10:38 2020	(r356480)
> @@ -881,8 +881,8 @@ nvme_ctrlr_hmb_alloc(struct nvme_controller *ctrlr)
>  	int err, i;
>  	uint64_t max;
>  
> -	/* Limit HMB to 1% of RAM size per device by default. */
> -	max = (uint64_t)physmem * PAGE_SIZE / 100;
> +	/* Limit HMB to 5% of RAM size per device by default. */
> +	max = (uint64_t)physmem * PAGE_SIZE / 20;
>  	TUNABLE_UINT64_FETCH("hw.nvme.hmb_max", &max);
>  
>  	min = (long long unsigned)ctrlr->cdata.hmmin * 4096;