Modify contigmalloc1() so that the free page queues lock is not held when

vm_page_free() is called.  The problem with holding this lock is that it is
a spin lock and vm_page_free() may attempt the acquisition of a different
default-type lock.

2 files changed, 15 insertions, 4 deletions

diff --git a/sys/vm/vm_contig.c b/sys/vm/vm_contig.c
index 311a87a..bc78dd0 100644
--- a/sys/vm/vm_contig.c
+++ b/sys/vm/vm_contig.c
@@ -169,6 +169,7 @@ contigmalloc1(
 	start = 0;
 	for (pass = 0; pass <= 1; pass++) {
 		vm_page_lock_queues();
+again0:
 		mtx_lock_spin(&vm_page_queue_free_mtx);
 again:
 		/*
@@ -213,6 +214,7 @@ again1:
 				goto again;
 			}
 		}
+		mtx_unlock_spin(&vm_page_queue_free_mtx);
 		for (i = start; i < (start + size / PAGE_SIZE); i++) {
 			vm_page_t m = &pga[i];
 
@@ -220,13 +222,23 @@ again1:
 				object = m->object;
 				if (!VM_OBJECT_TRYLOCK(object)) {
 					start++;
-					goto again;
+					goto again0;
 				}
 				vm_page_busy(m);
 				vm_page_free(m);
 				VM_OBJECT_UNLOCK(object);
 			}
 		}
+		mtx_lock_spin(&vm_page_queue_free_mtx);
+		for (i = start; i < (start + size / PAGE_SIZE); i++) {
+			pqtype = pga[i].queue - pga[i].pc;
+			if ((VM_PAGE_TO_PHYS(&pga[i]) !=
+			    (VM_PAGE_TO_PHYS(&pga[i - 1]) + PAGE_SIZE)) ||
+			    (pqtype != PQ_FREE)) {
+				start++;
+				goto again;
+			}
+		}
 		for (i = start; i < (start + size / PAGE_SIZE); i++) {
 			vm_page_t m = &pga[i];
 			vm_pageq_remove_nowakeup(m);
diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index 853178a..ae1673a 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -206,12 +206,11 @@ vm_page_startup(vm_offset_t starta, vm_offset_t enda, vm_offset_t vaddr)
 	end = phys_avail[biggestone+1];
 
 	/*
-	 * Initialize the locks.  Recursive acquisition of the vm page
-	 * queue free mutex begins in contigmalloc1().  
+	 * Initialize the locks.
 	 */
 	mtx_init(&vm_page_queue_mtx, "vm page queue mutex", NULL, MTX_DEF);
 	mtx_init(&vm_page_queue_free_mtx, "vm page queue free mutex", NULL,
-	   MTX_RECURSE | MTX_SPIN);
+	    MTX_SPIN);
 
 	/*
 	 * Initialize the queue headers for the free queue, the active queue