Quoting Mark Kettenis (mark.kette...@xs4all.nl): > An accurate description would be that the percentage is actually the > percentage of "DMA-reachable" physical memory the buffer cache may > use. The minimum percentage is 5% and the maximum is 90%. > > But documenting it like that needs an explanation of what > "DMA-reachable" memory is.
In practice, my amd64 systems with 32GB memory and kern.bufcachepercent=90 has the cache capped around 3GB. This surprised me greatly, so I'm all ears if anyone else has ideas on how we can document this.
