On Fri, Jun 04, 2021 at 11:07:42AM +1000, Alistair Popple wrote:

On Friday, 4 June 2021 12:47:40 AM AEST Peter Xu wrote:

quoted

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On Thu, Jun 03, 2021 at 09:39:32PM +1000, Alistair Popple wrote:

quoted

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;

I did look at pageout() but still missed this small helper indeed (while it's
so important to know..), thanks!

-- 
Peter Xu