On 2016/7/22 17:04, Vlastimil Babka wrote:
On 07/22/2016 10:56 AM, Xishi Qiu wrote:
I find all the watermarks in mm/compaction.c are low_wmark_pages(),
so why not use high watermark to determine whether compact is finished?
Why would you use high watermark? Quite the opposite, I want to move towards min watermark (precisely, the one in alloc_flags which is usually min) in this series:
this is fast path, use use low_wmark_pages() in __zone_watermark_ok()
this is slow path, usually use min_wmark_pages()
Yes, and compaction should be finished when allocation can succeed, so match __alloc_pages_slowpath().
Sounds reasonable, but now we have kcompactd which called from kswapd,
so still use low wmark?
use high_wmark_pages() to determine whether zone is balanced