Am 10.08.2011 um 10:47 schrieb Jeremy Chadwick: > On Wed, Aug 10, 2011 at 08:27:27AM +0000, Holger Kipp wrote: >> >> Am 10.08.2011 um 10:09 schrieb Daniel Kalchev: >> >>> On 10.08.11 10:47, Jeremy Chadwick wrote: >>>> On Wed, Aug 10, 2011 at 10:13:14AM +0300, Daniel Kalchev wrote: >>>>> I am more concerned that with 32GB of swap in single device I could not >>>>> dump kernel core, with 64GB of RAM. >>>> My apologies if I've misunderstood something, but why does this of any >>>> concern? Machine has 64GB RAM. You have a single swap slice that's >>>> effectively 32GB. How is a kernel panic worth of 64GB RAM going to fit >>>> into a 32GB swap slice? >>>> >>> The swap partitions are 64GB, it is only that FreeBSD refuses to use more >>> than 32GB of each for swap. But.. it might happily dump core to the whole >>> partition, tests will show. >> >> I doubt it. Have you tried increasing kern.maxswzone? It is the size in KB >> (for 32GB it is set to 33554432). >> kern.maxswzone: Maximum memory for swap metadata > > The variable is set to 32MBytes, not 32GBytes. The default size is > defined as variable VM_SWZONE_SIZE_MAX, which is 32*1024*1024 per > sys/i386/include/param.h and sys/amd64/include/param.h. > > Furthermore, this variable does not do what you're implying.
Ah, then I misinterpreted the output of "man loader" which states: kern.maxswzone Limits the amount of KVM to be used to hold swap meta information, which directly governs the maximum amount of swap the system can support. > So we're back to where we started: swap slices/partitions can be greater > than 32GBytes in size, but "something" is limiting the maximum amount of > memory which can be dumped to a single swap swap to 32GBytes. Anyway, there is one thing in /usr/src/sys/vm/swap_pager.c (so if you get this warning (reducing size to maximum of... per swap unit)), this might be the reason: /* * If we go beyond this, we get overflows in the radix * tree bitmap code. */ mblocks = 0x40000000 / BLIST_META_RADIX; if (nblks > mblocks) { printf("WARNING: reducing size to maximum of %lu blocks per swap unit\n", mblocks); nblks = mblocks; } Hope this is of some help. Best regards, Holger -- Holger Kipp Diplom-Mathematiker Senior Consultant Tel. : +49 30 436 58 114 Fax. : +49 30 436 58 214 Mobil: +49 178 36 58 114 Email: holger.k...@alogis.com alogis AG Alt-Moabit 90b D-10559 Berlin web : http://www.alogis.com ---------------------------------------------------------- alogis AG Sitz/Registergericht: Berlin/AG Charlottenburg, HRB 71484 Vorstand: Arne Friedrichs, Joern Samuelson Aufsichtsratsvorsitzender: Reinhard Mielke _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"