Index: uvm/uvm_extern.h
===================================================================
RCS file: /cvsroot/src/sys/uvm/uvm_extern.h,v
retrieving revision 1.231
diff -p -u -r1.231 uvm_extern.h
--- uvm/uvm_extern.h	14 Aug 2020 09:06:15 -0000	1.231
+++ uvm/uvm_extern.h	18 Dec 2020 03:29:16 -0000
@@ -398,7 +398,7 @@ struct uvmexp {
 	/* daemon counters.  XXX: should be 64-bit counters */
 	int pdwoke;	/* number of times daemon woke up */
 	int pdrevs;	/* number of times daemon rev'd clock hand */
-	int _unused3;
+	int pdkeeprun;	/* number of times daemon did not sleep */
 	int pdfreed;	/* number of pages daemon freed since boot */
 	int pdscans;	/* number of pages daemon scanned since boot */
 	int pdanscan;	/* number of anonymous pages scanned by daemon */
@@ -411,6 +411,9 @@ struct uvmexp {
 	int pdreanon;	/* anon pages reactivated due to thresholds */
 	int pdrefile;	/* file pages reactivated due to thresholds */
 	int pdreexec;	/* executable pages reactivated due to thresholds */
+	int pdplwoke;	/* number of times pool drain thread woke up */
+	int pdplcycled;	/* number of times pool drain cycled all pools */
+	int pdpldrained;/* number of times pool_drain() called */
 
 	int bootpages;  /* number of pages stolen at boot */
 };
Index: uvm/uvm_pdaemon.c
===================================================================
RCS file: /cvsroot/src/sys/uvm/uvm_pdaemon.c,v
retrieving revision 1.131
diff -p -u -r1.131 uvm_pdaemon.c
--- uvm/uvm_pdaemon.c	4 Nov 2020 01:30:19 -0000	1.131
+++ uvm/uvm_pdaemon.c	18 Dec 2020 03:29:16 -0000
@@ -282,6 +282,7 @@ uvm_pageout(void *arg)
 			UVMHIST_LOG(pdhist,"  <<WOKE UP>>",0,0,0,0);
 		} else {
 			mutex_spin_exit(&uvmpd_lock);
+			uvmexp.pdkeeprun++;
 		}
 
 		/*
@@ -1020,12 +1021,12 @@ uvmpd_pool_drain_thread(void *arg)
 		if (!uvmpd_pool_drain_run) {
 			lastslept = getticks();
 			cv_wait(&uvmpd_pool_drain_cv, &uvmpd_lock);
+			uvmexp.pdplwoke++;
 			if (getticks() != lastslept) {
 				cycled = false;
 				firstpool = NULL;
 			}
 		}
-		uvmpd_pool_drain_run = false;
 		mutex_exit(&uvmpd_lock);
 
 		/*
@@ -1034,6 +1035,7 @@ uvmpd_pool_drain_thread(void *arg)
 		 */
 		if (cycled) {
 			kpause("uvmpdlmt", false, 1, NULL);
+			uvmexp.pdplcycled++;
 			cycled = false;
 			firstpool = NULL;
 		}
@@ -1058,6 +1060,7 @@ uvmpd_pool_drain_thread(void *arg)
 		 * drain a pool, and then re-enable the freelist cache.
 		 */
 		(void)pool_drain(&curpool);
+		uvmexp.pdpldrained++;
 		KASSERT(curpool != NULL);
 		if (firstpool == NULL) {
 			firstpool = curpool;
@@ -1065,6 +1068,11 @@ uvmpd_pool_drain_thread(void *arg)
 			cycled = true;
 		}
 		uvm_pgflcache_resume();
+
+		uvmpd_pool_drain_run =
+		    (uvm_km_va_starved_p() ||
+		    uvm_availmem(false) + uvmexp.paging < uvmexp.freetarg);
+		yield();
 	}
 	/*NOTREACHED*/
 }
Index: uvm/uvm_stat.c
===================================================================
RCS file: /cvsroot/src/sys/uvm/uvm_stat.c,v
retrieving revision 1.46
diff -p -u -r1.46 uvm_stat.c
--- uvm/uvm_stat.c	14 Jun 2020 21:41:42 -0000	1.46
+++ uvm/uvm_stat.c	18 Dec 2020 03:29:16 -0000
@@ -133,8 +133,10 @@ uvmexp_print(void (*pr)(const char *, ..
 	    uvmexp.pdanscan);
 	(*pr)("    busy=%d, freed=%d, reactivate=%d, deactivate=%d\n",
 	    uvmexp.pdbusy, uvmexp.pdfreed, uvmexp.pdreact, uvmexp.pddeact);
-	(*pr)("    pageouts=%d, pending=%d, nswget=%d\n", uvmexp.pdpageouts,
-	    uvmexp.pdpending, uvmexp.nswget);
+	(*pr)("    pageouts=%d, pending=%d, nswget=%d, keeprun=%d\n",
+	    uvmexp.pdpageouts, uvmexp.pdpending, uvmexp.nswget, uvmexp.pdkeeprun);
+	(*pr)("    pdplwoke=%d, pdplcycled=%d, pdpldrained=%d\n",
+	    uvmexp.pdplwoke, uvmexp.pdplcycled, uvmexp.pdpldrained);
 	(*pr)("    nswapdev=%d, swpgavail=%d\n",
 	    uvmexp.nswapdev, uvmexp.swpgavail);
 	(*pr)("    swpages=%d, swpginuse=%d, swpgonly=%d, paging=%d\n",