Handle a bit more work without taking the kernel lock. This should avoid

taking the kernel lock on when operating on the kernel_map when called from
all kernel memory allocation interfaces.

ok visa@, mlarkin@

1 files changed, 12 insertions, 2 deletions

diff --git a/sys/uvm/uvm_map.c b/sys/uvm/uvm_map.c
index 2638d821faf..497bc78195a 100644
--- a/sys/uvm/uvm_map.c
+++ b/sys/uvm/uvm_map.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_map.c,v 1.243 2019/04/23 13:35:12 visa Exp $	*/
+/*	$OpenBSD: uvm_map.c,v 1.244 2019/05/16 04:24:14 kettenis Exp $	*/
 /*	$NetBSD: uvm_map.c,v 1.86 2000/11/27 08:40:03 chs Exp $	*/
 
 /*
@@ -1538,9 +1538,19 @@ uvm_mapent_tryjoin(struct vm_map *map, struct vm_map_entry *entry,
 void
 uvm_unmap_detach(struct uvm_map_deadq *deadq, int flags)
 {
-	struct vm_map_entry *entry;
+	struct vm_map_entry *entry, *tmp;
 	int waitok = flags & UVM_PLA_WAITOK;
 
+	TAILQ_FOREACH_SAFE(entry, deadq, dfree.deadq, tmp) {
+		/* Skip entries for which we have to grab the kernel lock. */
+		if (entry->aref.ar_amap || UVM_ET_ISSUBMAP(entry) ||
+		    UVM_ET_ISOBJ(entry))
+			continue;
+
+		TAILQ_REMOVE(deadq, entry, dfree.deadq);
+		uvm_mapent_free(entry);
+	}
+
 	if (TAILQ_EMPTY(deadq))
 		return;