On Thu, Mar 22, 2012 at 8:03 AM, John Baldwin <j...@freebsd.org> wrote: > On Wednesday, March 21, 2012 4:20:17 pm Mark Saad wrote: >> On Wed, Mar 21, 2012 at 12:39 PM, Sergey Kandaurov <pluk...@gmail.com> wrote: >> > On 21 March 2012 19:19, John Baldwin <j...@freebsd.org> wrote: >> >> On Tuesday, March 20, 2012 11:37:57 am Sergey Kandaurov wrote: >> >>> On 22 November 2011 19:29, Mark Saad <nones...@longcount.org> wrote: >> >>> > Hello All >> >>> >> >>> [found this mail in my drafts, not sure if my answer is still useful] >> >>> >> >>> > I want to get to the bottom of a warning in dmesg. On 7.2-RELEASE and >> >>> > 7.3-RELEASE I have seen the following warning in dmesg. >> >>> > >> >>> > Approaching the limit on PV entries, consider increasing either the >> >>> > vm.pmap.shpgperproc or the vm.pmap.pv_entry_max sysctl. >> >>> > >> >>> > So looking around I see a few posts here and there about how to tune >> >>> > the sysctls to address the warning however I am not 100% sure what >> >>> > each value does. >> >>> > It appears changing vm.pmap.shpgperproc affects the value of >> >>> > vm.pmap.pv_entry_max . Can someone explain the relationship of the two >> >>> > sysctls. Also >> >>> >> >>> This is how they are calculated. >> >>> >> >>> pv_entry_max = shpgperproc * maxproc + cnt.v_page_count; >> >>> >> >>> and, respectively, >> >>> >> >>> shpgperproc = (pv_entry_max - cnt.v_page_count) / maxproc; >> >>> >> >>> So, changing one sysctl will change another and vice versa. >> >>> >> >>> > what pitfalls of changing them are. >> >>> >> >>> Not known to me (on amd64 platform). >> >>> I have had vm.pmap.shpgperproc=15000 on 8.1 amd64 with 4G RAM >> >>> to make some badly written commercial software to work until it >> >>> was decommissioned to the scrap. >> >> >> >> FYI, Alan just removed this warning and the associated sysctls from HEAD >> >> yesterday because they were made obsolete several years ago. I think >> >> they are >> >> obsolete even on 7. Certainly on 8. >> > >> > Yep, and since switching to direct map (somewhere around 7.x on amd64?) >> > made PV entry limit factually obsolete, this is really cool. >> > >> > -- >> > wbr, >> > pluknet >> >> Interesting so this warning is relevant in 7.x ? > > No, looks like it was obsolete starting with 7.0. > > -- > John Baldwin
Any chance it could be mfc'ed to 7-STABLE ? -- mark saad | nones...@longcount.org _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
