Re: [PATCH v9 07/10] mm: Device exclusive memory access

[Alistair Popple]

On Friday, 4 June 2021 12:47:40 AM AEST Peter Xu wrote:
> External email: Use caution opening links or attachments
> 
> On Thu, Jun 03, 2021 at 09:39:32PM +1000, Alistair Popple wrote:
> > Reclaim won't run on the page due to the extra references from the special
> > swap entries.
> 
> That sounds reasonable, but I didn't find the point that stops it, probably
> due to my limited knowledge on the reclaim code.  Could you elaborate?

Sure, it isn't immediately obvious but it ends up being detected at the start 
of is_page_cache_freeable() in the pageout code:


static pageout_t pageout(struct page *page, struct address_space *mapping)
{

[...]

	if (!is_page_cache_freeable(page))
		return PAGE_KEEP;

 - Alistair

> --
> Peter Xu