On Wed, 16 Sep 2020 09:40:10 +0800 "Huang\, Ying" [off-list ref] wrote:

Matthew Wilcox [off-list ref] writes:

quoted

On Tue, Sep 15, 2020 at 09:40:45AM +0200, SeongJae Park wrote:

quoted

On Tue,  8 Sep 2020 20:55:38 +0100 "Matthew Wilcox (Oracle)" [off-list ref] wrote:

quoted

Remove the assumption that a compound page has HPAGE_PMD_NR pins from
the page cache.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Huang Ying <redacted>

quoted

quoted

-	int page_cache_pins = PageTransHuge(page) && PageSwapCache(page) ?
-		HPAGE_PMD_NR : 1;
+	int page_cache_pins = thp_nr_pages(page);

Is it ok to remove the PageSwapCache() check?

I think so?  My understanding is that it was added in commit bd4c82c22c36
to catch shmem pages, but there was really no reason to only do this for
shmem pages.

The original implementation is to write out Anonymous THP (not shmem).
The code should work after the changing, because now any THP except
normal Anonymous THP in swap cache will be split during reclaiming
already.

Thanks for the kind explanation :)

Acked-by: "Huang, Ying" <redacted>

Reviewed-by: SeongJae Park <redacted>


Thanks,
SeongJae Park