Author: markj Date: Tue Sep 18 17:51:45 2018 New Revision: 338755 URL: https://svnweb.freebsd.org/changeset/base/338755
Log: Only update the domain cursor once in keg_fetch_slab(). We drop the keg lock when we go to actually allocate the slab, allowing other threads to advance the cursor. This can cause us to exit the round-robin loop before having attempted allocations from all domains, resulting in a hang during a subsequent blocking allocation attempt from a depleted domain. Reported and tested by: Jan Bramkamp <[email protected]> Reviewed by: alc, cem Approved by: re (gjb) Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D17209 Modified: head/sys/vm/uma_core.c Modified: head/sys/vm/uma_core.c ============================================================================== --- head/sys/vm/uma_core.c Tue Sep 18 16:57:04 2018 (r338754) +++ head/sys/vm/uma_core.c Tue Sep 18 17:51:45 2018 (r338755) @@ -2698,10 +2698,8 @@ again: LIST_INSERT_HEAD(&dom->ud_part_slab, slab, us_link); return (slab); } - if (rr) { - keg->uk_cursor = (keg->uk_cursor + 1) % vm_ndomains; - domain = keg->uk_cursor; - } + if (rr) + domain = (domain + 1) % vm_ndomains; } while (domain != start); /* Retry domain scan with blocking. */ _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "[email protected]"
