On 10/10/08, Mark Tinguely <[EMAIL PROTECTED]> wrote: >> > vm.pmap.pv_entry_count: 583006 >> > vm.pmap.shpgperproc: 200 >> > vm.pmap.pv_entry_max: 2243305 >> > >> > The system: >> > FreeBSD .... 7.0-RELEASE-p5 FreeBSD 7.0-RELEASE-p5 #0: Wed Oct 1 >> > 07:51:58 UTC 2008 >> > [EMAIL PROTECTED]:/usr/obj/usr/src/sys/GENERIC amd64 >> > >> > Can someone briefly explain what this is telling me and how to decide >> > which sysctl to increase? I have found some old postings that predate >> > the sysctls that suggested increasing shpgperproc in the kernel >> > configuration, about 50 at a time until the problem goes away, but I >> > still have no clue what that is accomplishing. > > what (simplified): > the pv_entry helps the virtual memory system track physical pages, so a > physical page can be shared with another process or another virtual address. > > In the i386/amd64 the pv_entry entries are allocated in page size "chunks" > on a per process memory map basis. This helps reduce redundant pointers > and overall saves memory. > > "shpgperproc" can be read as "the number of shared pages per proceess". > pv_entry_max is calculated from shpgperproc (and on the amd64, shpgperproc > can be derived from setting the vm.pmap.pv_entry_max). > > On the amd64, the values can be adjusted by sysctl, but on the i386 > the values must be compiled into the kernel. > > There are some automatic adjustments in the calculation of the number > of pv_entry, but the warnings are given early enough to help aid in the > tweaking of the value. The advice of slowly increasing vm.pmap.shpgperproc > is probably the best solution. I would adjust up slower than 50 (25% > increase seems to be pretty high). > > --Mark Tinguely. >
Thanks. I'll see what happens. In amd64/7.0 is there any chance running out of pv_entrys would show up as failures in interprocess communication rather than a panic? The original symptom was that certain web pages (or jailed servers, I'm not sure) were unreachable, as if the firewall were misconfigured, until the system was rebooted. I didn't get to look at the system before it was rebooted, and I find very little in the logs to explain what was going on. Thanks again, - Bob [EMAIL PROTECTED] _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
