Author: markj Date: Fri Aug 2 18:01:47 2019 New Revision: 350540 URL: https://svnweb.freebsd.org/changeset/base/350540
Log: Only check the blessings table for known LORs. Previously we would check for blessings before marking a given lock pair as reversed, so each "reversed" lock acquisition would require a linear scan of the table. Instead, check the table after marking the pair as reversed but before generating a report. Reviewed by: jhb MFC after: 1 week Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D21135 Modified: head/sys/kern/subr_witness.c Modified: head/sys/kern/subr_witness.c ============================================================================== --- head/sys/kern/subr_witness.c Fri Aug 2 16:05:36 2019 (r350539) +++ head/sys/kern/subr_witness.c Fri Aug 2 18:01:47 2019 (r350540) @@ -1344,14 +1344,6 @@ witness_checkorder(struct lock_object *lock, int flags * is allowed or has already been yelled about. */ - /* - * If the lock order is blessed, just bail. We don't - * look for other lock order violations though, which - * may be a bug. - */ - if (blessed(w, w1)) - goto out; - /* Bail if this violation is known */ if (w_rmatrix[w1->w_index][w->w_index] & WITNESS_REVERSAL) goto out; @@ -1361,6 +1353,14 @@ witness_checkorder(struct lock_object *lock, int flags w_rmatrix[w->w_index][w1->w_index] |= WITNESS_REVERSAL; w->w_reversed = w1->w_reversed = 1; witness_increment_graph_generation(); + + /* + * If the lock order is blessed, bail before logging + * anything. We don't look for other lock order + * violations though, which may be a bug. + */ + if (blessed(w, w1)) + goto out; mtx_unlock_spin(&w_mtx); #ifdef WITNESS_NO_VNODE @@ -2650,6 +2650,9 @@ restart: &tmp_data2->wlod_stack); } mtx_unlock_spin(&w_mtx); + + if (blessed(tmp_w1, tmp_w2)) + continue; sbuf_printf(sb, "\nLock order reversal between \"%s\"(%s) and \"%s\"(%s)!\n", _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
