svn commit: r330746 - user/jeff/numa/sys/vm

[Jeff Roberson]

Author: jeff
Date: Sat Mar 10 22:47:26 2018
New Revision: 330746
URL: https://svnweb.freebsd.org/changeset/base/330746

Log:
  More complete fix for the FT iterator problem.  When we switch from FT to
  RR we may revisit the original domain and double count it against the
  iteration count.  We could track the original domain and skip it on the
  RR pass but this would involve more state and checks.  Just bump the
  count an extra time instead.
  
  Reported by:    mjg

Modified:
  user/jeff/numa/sys/vm/vm_domainset.c

Modified: user/jeff/numa/sys/vm/vm_domainset.c
==============================================================================
--- user/jeff/numa/sys/vm/vm_domainset.c	Sat Mar 10 22:07:57 2018	(r330745)
+++ user/jeff/numa/sys/vm/vm_domainset.c	Sat Mar 10 22:47:26 2018	(r330746)
@@ -94,7 +94,8 @@ static void
 vm_domainset_iter_rr(struct vm_domainset_iter *di, int *domain)
 {
 
-	*domain = di->di_domain->ds_order[++(*di->di_iter) % di->di_domain->ds_cnt];
+	*domain = di->di_domain->ds_order[
+	    ++(*di->di_iter) % di->di_domain->ds_cnt];
 }
 
 static void
@@ -155,7 +156,11 @@ vm_domainset_iter_first(struct vm_domainset_iter *di, 
 	case DOMAINSET_POLICY_FIRSTTOUCH:
 		*domain = PCPU_GET(domain);
 		if (DOMAINSET_ISSET(*domain, &di->di_domain->ds_mask)) {
-			di->di_n = di->di_domain->ds_cnt;
+			/*
+			 * Add an extra iteration because we will visit the
+			 * current domain a second time in the rr iterator.
+			 */
+			di->di_n = di->di_domain->ds_cnt + 1;
 			break;
 		}
 		/*