On Thu, 23 Apr 2020 14:24:53 -0700 "Greg A. Woods" <wo...@planix.com> wrote:
> At Thu, 23 Apr 2020 11:56:08 +0100, Sad Clouds > <cryintotheblue...@gmail.com> wrote: Subject: Re: Linux compat and > swap > > > > On Thu, 23 Apr 2020 10:56:15 +0100 > > Mike Pumford <mpumf...@mudcovered.org.uk> wrote: > > > > > If you have both memory intensive and filesystem intensive > > > processes running on a NetBSD system the kernel filesystem cache > > > can end up evicting programs running in the background that are > > > inactive which then take a LONG time to recover. For a system > > > with a reasonable amount of memory I found the vm.filemin and > > > vm.filemax needed to be tweaked so that filesystem cache was more > > > likely to be tweaked than program code. > > > > Is this correct? I always thought that file cache was opportunistic, > > i.e. it will use all free memory, but under no circumstances it > > should evict any pages of running programs. The opposite should > > happen, i.e. any program using memory should be allowed to steal it > > from file cache at any time. > > > > Mike's description is correct. > > Processes can only take over memory from the file cache if the value > for vm.filemin is small enough. That is, after all, what vm.filemin > means. OK I stand corrected, I changed vm.filemax from 5 to 90 and then did "dd if=/dev/zero of=out bs=1m count=5000" on a VM with 4GiB of RAM and a process which malloc()ed 3GiB. This time it started swapping pages to disk. vm.anonmin=60 vm.anonmax=90 vm.filemin=1 #vm.filemax=5 vm.filemax=90 vm.execmin=5 vm.execmax=60
