vfs: track how many times vn_alloc blocked on hitting the vnode limit

dzvon · Aug 18, 2023 · 64e881f · 64e881f
1 parent 57a3b81
commit 64e881f
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
@@ -1712,6 +1712,10 @@ vtryrecycle(struct vnode *vp)
  * vnlru to clear things up, but ultimately always performs a M_WAITOK allocation.
  */
 static u_long vn_alloc_cyclecount;
+static u_long vn_alloc_sleeps;
+
+SYSCTL_ULONG(_vfs, OID_AUTO, vnode_alloc_sleeps, CTLFLAG_RD, &vn_alloc_sleeps, 0,
+    "Number of times vnode allocation blocked waiting on vnlru");
 
 static struct vnode * __noinline
 vn_alloc_hard(struct mount *mp)
@@ -1746,6 +1750,7 @@ vn_alloc_hard(struct mount *mp)
 		 * Wait for space for a new vnode.
 		 */
 		vnlru_kick();
+		vn_alloc_sleeps++;
 		msleep(&vnlruproc_sig, &vnode_list_mtx, PVFS, "vlruwk", hz);
 		if (atomic_load_long(&numvnodes) + 1 > desiredvnodes &&
 		    vnlru_read_freevnodes() > 1)