- Update vm_pageout_deficit using atomic operations. It's a simple

   counter outside the scope of existing locks.
 - Eliminate a redundant clearing of vm_pageout_deficit.

3 files changed, 7 insertions, 7 deletions

diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index a4e5b6e..3293ab4 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -2757,7 +2757,8 @@ allocbuf(struct buf *bp, int size)
 					    VM_ALLOC_SYSTEM | VM_ALLOC_WIRED);
 					if (m == NULL) {
 						VM_WAIT;
-						vm_pageout_deficit += desiredpages - bp->b_npages;
+						atomic_add_int(&vm_pageout_deficit,
+						    desiredpages - bp->b_npages);
 					} else {
 						vm_page_lock_queues();
 						vm_page_wakeup(m);
@@ -3488,7 +3489,8 @@ tryagain:
 		    VM_ALLOC_SYSTEM | VM_ALLOC_WIRED);
 		vm_object_unlock(kernel_object);
 		if (!p) {
-			vm_pageout_deficit += (to - from) >> PAGE_SHIFT;
+			atomic_add_int(&vm_pageout_deficit,
+			    (to - from) >> PAGE_SHIFT);
 			VM_WAIT;
 			goto tryagain;
 		}
diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index 56abce4..bbdc77b 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -805,7 +805,7 @@ loop:
 			if (cnt.v_cache_count > 0)
 				printf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", cnt.v_cache_count);
 #endif
-			vm_pageout_deficit++;
+			atomic_add_int(&vm_pageout_deficit, 1);
 			pagedaemon_wakeup();
 			return (NULL);
 		}
@@ -821,7 +821,7 @@ loop:
 		 */
 		mtx_unlock_spin(&vm_page_queue_free_mtx);
 		splx(s);
-		vm_pageout_deficit++;
+		atomic_add_int(&vm_pageout_deficit, 1);
 		pagedaemon_wakeup();
 		return (NULL);
 	}
diff --git a/sys/vm/vm_pageout.c b/sys/vm/vm_pageout.c
index 84d4cac..ec759db 100644
--- a/sys/vm/vm_pageout.c
+++ b/sys/vm/vm_pageout.c
@@ -694,8 +694,7 @@ vm_pageout_scan(int pass)
 	 */
 	vm_pageout_pmap_collect();
 
-	addl_page_shortage_init = vm_pageout_deficit;
-	vm_pageout_deficit = 0;
+	addl_page_shortage_init = atomic_readandclear_int(&vm_pageout_deficit);
 
 	/*
 	 * Calculate the number of pages we want to either free or move
@@ -1479,7 +1478,6 @@ vm_pageout()
 			cnt.v_pdwakeups++;
 		splx(s);
 		vm_pageout_scan(pass);
-		vm_pageout_deficit = 0;
 	}
 }