Re: [PATCH 6/8] mm/vmscan: Centralise timeout values for reclaim_throttle

[Vlastimil Babka]

On 10/8/21 15:53, Mel Gorman wrote:
> Neil Brown raised concerns about callers of reclaim_throttle specifying
> a timeout value. The original timeout values to congestion_wait() were
> probably pulled out of thin air or copy&pasted from somewhere else.
> This patch centralises the timeout values and selects a timeout based
> on the reason for reclaim throttling. These figures are also pulled
> out of the same thin air but better values may be derived
> 
> Running a workload that is throttling for inappropriate periods
> and tracing mm_vmscan_throttled can be used to pick a more appropriate
> value. Excessive throttling would pick a lower timeout where as
> excessive CPU usage in reclaim context would select a larger timeout.
> Ideally a large value would always be used and the wakeups would
> occur before a timeout but that requires careful testing.
> 
> Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>

Acked-by: Vlastimil Babka <vbabka@xxxxxxx>