About pmap_mapdev() & pmap_unmapdev()

Kohji Okuno okuno.kohji at jp.panasonic.com
Mon Oct 6 06:25:41 UTC 2014


Hi Konstantin,

I tested your patch. It was no problem.
Thank you for your kind correspondence.

Regards,
 Kohji Okuno

> On Sat, Oct 04, 2014 at 05:53:26PM +0900, Kohji Okuno wrote:
>> Hi, Konstantin,
>> 
>> > At the end of the mail is commit candidate.  I did not even compiled this.
>> > Can you test and report back, please ?
>> 
>> Could you check the following?
>> (1) should use kernel_pmap->pm_stats.resident_count
>>                           ^^^
>>     I'm sorry. My patch was wrong. 
> As well as mine.
> 
>> 
>> (2) should use pmap_resident_count_inc() in amd64.
> Correct.
> 
>> 
>> 
>> I will test, later.
>> 
>> In addtion, I have one question.
>> In current and 10-stable, is vm_map_delete() called by kva_free()?
> No, kva_free() only releases the vmem backing, leaving the page
> tables intact.  This is why I only did the stable/9 patch.
> 
>> If vm_map_delete() is called, this fix is needed in current and
>> 10-stable, I think.
> 
> Updated patch below.
> 
> Index: amd64/amd64/pmap.c
> ===================================================================
> --- amd64/amd64/pmap.c	(revision 272506)
> +++ amd64/amd64/pmap.c	(working copy)
> @@ -5040,6 +5040,9 @@ pmap_mapdev_attr(vm_paddr_t pa, vm_size_t size, in
>  	pa = trunc_page(pa);
>  	for (tmpsize = 0; tmpsize < size; tmpsize += PAGE_SIZE)
>  		pmap_kenter_attr(va + tmpsize, pa + tmpsize, mode);
> +	PMAP_LOCK(kernel_pmap);
> +	pmap_resident_count_inc(kernel_pmap, OFF_TO_IDX(size));
> +	PMAP_UNLOCK(kernel_pmap);
>  	pmap_invalidate_range(kernel_pmap, va, va + tmpsize);
>  	pmap_invalidate_cache_range(va, va + tmpsize);
>  	return ((void *)(va + offset));
> Index: i386/i386/pmap.c
> ===================================================================
> --- i386/i386/pmap.c	(revision 272506)
> +++ i386/i386/pmap.c	(working copy)
> @@ -5066,10 +5066,14 @@ pmap_mapdev_attr(vm_paddr_t pa, vm_size_t size, in
>  	size = roundup(offset + size, PAGE_SIZE);
>  	pa = pa & PG_FRAME;
>  
> -	if (pa < KERNLOAD && pa + size <= KERNLOAD)
> +	if (pa < KERNLOAD && pa + size <= KERNLOAD) {
>  		va = KERNBASE + pa;
> -	else
> +	} else {
>  		va = kmem_alloc_nofault(kernel_map, size);
> +		PMAP_LOCK(kernel_pmap);
> +		kernel_pmap->pm_stats.resident_count += OFF_TO_IDX(size);
> +		PMAP_UNLOCK(kernel_pmap);
> +	}
>  	if (!va)
>  		panic("pmap_mapdev: Couldn't alloc kernel virtual memory");
>  
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