On 07/22/2016 10:56 AM, Xishi Qiu wrote:
Hi, 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:
https://lkml.org/lkml/2016/6/24/222 especially: https://lkml.org/lkml/2016/6/24/214
e.g. __alloc_pages_nodemask() get_page_from_freelist() this is fast path, use use low_wmark_pages() in __zone_watermark_ok() __alloc_pages_slowpath() this is slow path, usually use min_wmark_pages()
Yes, and compaction should be finished when allocation can succeed, so match __alloc_pages_slowpath().
kswapd balance_pgdat() use high_wmark_pages() to determine whether zone is balanced Thanks, Xishi Qiu
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