Messages in this thread | | | Date | Fri, 11 Dec 2009 08:51:54 -0500 | From | Rik van Riel <> | Subject | Re: [PATCH] vmscan: limit concurrent reclaimers in shrink_zone |
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On 12/11/2009 08:41 AM, Minchan Kim wrote: > Hi, Larry. > > On Fri, Dec 11, 2009 at 9:07 PM, Larry Woodman<lwoodman@redhat.com> wrote: >> Minchan Kim wrote: >>> >>> I like this. but why do you select default value as constant 8? >>> Do you have any reason? >>> >>> I think it would be better to select the number proportional to NR_CPU. >>> ex) NR_CPU * 2 or something. >>> >>> Otherwise looks good to me. >>> >>> Reviewed-by: Minchan Kim<minchan.kim@gmail.com> >>> >>> >> >> This is a per-zone count so perhaps a reasonable default is the number of >> CPUs on the >> NUMA node that the zone resides on ? > > For example, It assume one CPU per node. > It means your default value is 1. > On the CPU, process A try to reclaim HIGH zone. > Process B want to reclaim NORMAL zone. > But Process B can't enter reclaim path sincev throttle default value is 1 > Even kswap can't reclaim.
1) the value is per zone, so process B can go ahead
2) kswapd is always excempt from this limit, since there is only 1 kswapd per node anyway
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