Re: + filemap-make-the-accounting-of-thrashing-more-consistent.patch added to mm-unstable branch

[Joonsoo Kim]

2022년 8월 12일 (금) 오후 12:48, CGEL <cgel.zte@xxxxxxxxx>님이 작성:
>
> We have discussed related question before. See:
> https://lore.kernel.org/all/Yio17pXawRuuVJFO@xxxxxxxxxxx/
> The problem is that there is no suitable place to measure pagecache thrashing
> in fs level likes swap_readpage(). We have to measure it in folio_wait_bit_common().
>
> If we measure swap thrashing just in swap_readpage(), we will miss pagecache
> thrashing. If we measure swap thrashing in swap_readpage(), and measure
> pagecache thrashing in folio_wait_bit_common(), it will be rerpeated calculation.

Maybe, repeated calculation issue could be easily solved by
re-entrance detection on
delayacct_thrashing_start().

Thanks.