Annontate FreeBSD sysctls with CTLFLAG_MPSAFE

Without this, the sysctl system calls will acquire a global lock before
invoking the handler.  This is noticeable in some situations when
running top(1).  The global lock is mostly vestigal but continues to see
some use and so contention is still a problem; until the default sense
of the MPSAFE flag changes, we have to annotate each and every handler.

Reviewed-by: Allan Jude <[email protected]>
Reviewed-by: Ryan Moeller <[email protected]>
Signed-off-by: Mark Johnston <[email protected]>
Closes #10836

2 files changed, 31 insertions, 26 deletions

diff --git a/module/os/freebsd/spl/spl_kstat.c b/module/os/freebsd/spl/spl_kstat.c
index 655fe5a62..f21575142 100644
--- a/module/os/freebsd/spl/spl_kstat.c
+++ b/module/os/freebsd/spl/spl_kstat.c
@@ -349,50 +349,50 @@ kstat_install_named(kstat_t *ksp)
 			SYSCTL_ADD_PROC(&ksp->ks_sysctl_ctx,
 			    SYSCTL_CHILDREN(ksp->ks_sysctl_root),
 			    OID_AUTO, namelast,
-			    CTLTYPE_S32 | CTLFLAG_RD, ksp, i,
-			    kstat_sysctl, "I", namelast);
+			    CTLTYPE_S32 | CTLFLAG_RD | CTLFLAG_MPSAFE,
+			    ksp, i, kstat_sysctl, "I", namelast);
 			break;
 		case KSTAT_DATA_UINT32:
 			SYSCTL_ADD_PROC(&ksp->ks_sysctl_ctx,
 			    SYSCTL_CHILDREN(ksp->ks_sysctl_root),
 			    OID_AUTO, namelast,
-			    CTLTYPE_U32 | CTLFLAG_RD, ksp, i,
-			    kstat_sysctl, "IU", namelast);
+			    CTLTYPE_U32 | CTLFLAG_RD | CTLFLAG_MPSAFE,
+			    ksp, i, kstat_sysctl, "IU", namelast);
 			break;
 		case KSTAT_DATA_INT64:
 			SYSCTL_ADD_PROC(&ksp->ks_sysctl_ctx,
 			    SYSCTL_CHILDREN(ksp->ks_sysctl_root),
 			    OID_AUTO, namelast,
-			    CTLTYPE_S64 | CTLFLAG_RD, ksp, i,
-			    kstat_sysctl, "Q", namelast);
+			    CTLTYPE_S64 | CTLFLAG_RD | CTLFLAG_MPSAFE,
+			    ksp, i, kstat_sysctl, "Q", namelast);
 			break;
 		case KSTAT_DATA_UINT64:
 			SYSCTL_ADD_PROC(&ksp->ks_sysctl_ctx,
 			    SYSCTL_CHILDREN(ksp->ks_sysctl_root),
 			    OID_AUTO, namelast,
-			    CTLTYPE_U64 | CTLFLAG_RD, ksp, i,
-			    kstat_sysctl, "QU", namelast);
+			    CTLTYPE_U64 | CTLFLAG_RD | CTLFLAG_MPSAFE,
+			    ksp, i, kstat_sysctl, "QU", namelast);
 			break;
 		case KSTAT_DATA_LONG:
 			SYSCTL_ADD_PROC(&ksp->ks_sysctl_ctx,
 			    SYSCTL_CHILDREN(ksp->ks_sysctl_root),
 			    OID_AUTO, namelast,
-			    CTLTYPE_LONG | CTLFLAG_RD, ksp, i,
-			    kstat_sysctl, "L", namelast);
+			    CTLTYPE_LONG | CTLFLAG_RD | CTLFLAG_MPSAFE,
+			    ksp, i, kstat_sysctl, "L", namelast);
 			break;
 		case KSTAT_DATA_ULONG:
 			SYSCTL_ADD_PROC(&ksp->ks_sysctl_ctx,
 			    SYSCTL_CHILDREN(ksp->ks_sysctl_root),
 			    OID_AUTO, namelast,
-			    CTLTYPE_ULONG | CTLFLAG_RD, ksp, i,
-			    kstat_sysctl, "LU", namelast);
+			    CTLTYPE_ULONG | CTLFLAG_RD | CTLFLAG_MPSAFE,
+			    ksp, i, kstat_sysctl, "LU", namelast);
 			break;
 		case KSTAT_DATA_STRING:
 			SYSCTL_ADD_PROC(&ksp->ks_sysctl_ctx,
 			    SYSCTL_CHILDREN(ksp->ks_sysctl_root),
 			    OID_AUTO, namelast,
-			    CTLTYPE_STRING | CTLFLAG_RD, ksp, i,
-			    kstat_sysctl_string, "A", namelast);
+			    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
+			    ksp, i, kstat_sysctl_string, "A", namelast);
 			break;
 		default:
 			panic("unsupported type: %d", typelast);
@@ -417,14 +417,14 @@ kstat_install(kstat_t *ksp)
 			root = SYSCTL_ADD_PROC(&ksp->ks_sysctl_ctx,
 			    SYSCTL_CHILDREN(ksp->ks_sysctl_root),
 			    OID_AUTO, ksp->ks_name,
-			    CTLTYPE_STRING | CTLFLAG_RD, ksp, 0,
-			    kstat_sysctl_raw, "A", ksp->ks_name);
+			    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
+			    ksp, 0, kstat_sysctl_raw, "A", ksp->ks_name);
 		} else {
 			root = SYSCTL_ADD_PROC(&ksp->ks_sysctl_ctx,
 			    SYSCTL_CHILDREN(ksp->ks_sysctl_root),
 			    OID_AUTO, ksp->ks_name,
-			    CTLTYPE_OPAQUE | CTLFLAG_RD, ksp, 0,
-			    kstat_sysctl_raw, "", ksp->ks_name);
+			    CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE,
+			    ksp, 0, kstat_sysctl_raw, "", ksp->ks_name);
 		}
 		VERIFY(root != NULL);
 		break;
@@ -432,8 +432,8 @@ kstat_install(kstat_t *ksp)
 		root = SYSCTL_ADD_PROC(&ksp->ks_sysctl_ctx,
 		    SYSCTL_CHILDREN(ksp->ks_sysctl_root),
 		    OID_AUTO, ksp->ks_name,
-		    CTLTYPE_STRING | CTLFLAG_RD, ksp, 0,
-		    kstat_sysctl_io, "A", ksp->ks_name);
+		    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
+		    ksp, 0, kstat_sysctl_io, "A", ksp->ks_name);
 		break;
 	case KSTAT_TYPE_TIMER:
 	case KSTAT_TYPE_INTR:
diff --git a/module/os/freebsd/zfs/sysctl_os.c b/module/os/freebsd/zfs/sysctl_os.c
index b3cb7e7e4..c9b350a54 100644
--- a/module/os/freebsd/zfs/sysctl_os.c
+++ b/module/os/freebsd/zfs/sysctl_os.c
@@ -243,8 +243,9 @@ sysctl_vfs_zfs_arc_no_grow_shift(SYSCTL_HANDLER_ARGS)
 	return (0);
 }
 
-SYSCTL_PROC(_vfs_zfs, OID_AUTO, arc_no_grow_shift, CTLTYPE_U32 | CTLFLAG_RWTUN,
-    0, sizeof (uint32_t), sysctl_vfs_zfs_arc_no_grow_shift, "U",
+SYSCTL_PROC(_vfs_zfs, OID_AUTO, arc_no_grow_shift,
+    CTLTYPE_U32 | CTLFLAG_RWTUN | CTLFLAG_MPSAFE, 0, sizeof (uint32_t),
+    sysctl_vfs_zfs_arc_no_grow_shift, "U",
     "log2(fraction of ARC which must be free to allow growing)");
 
 int
@@ -275,10 +276,12 @@ param_set_arc_int(SYSCTL_HANDLER_ARGS)
 	return (0);
 }
 
-SYSCTL_PROC(_vfs_zfs, OID_AUTO, arc_min, CTLTYPE_ULONG | CTLFLAG_RWTUN,
+SYSCTL_PROC(_vfs_zfs, OID_AUTO, arc_min,
+    CTLTYPE_ULONG | CTLFLAG_RWTUN | CTLFLAG_MPSAFE,
     &zfs_arc_min, sizeof (zfs_arc_min), param_set_arc_long, "LU",
     "min arc size (LEGACY)");
-SYSCTL_PROC(_vfs_zfs, OID_AUTO, arc_max, CTLTYPE_ULONG | CTLFLAG_RWTUN,
+SYSCTL_PROC(_vfs_zfs, OID_AUTO, arc_max,
+    CTLTYPE_ULONG | CTLFLAG_RWTUN | CTLFLAG_MPSAFE,
     &zfs_arc_max, sizeof (zfs_arc_max), param_set_arc_long, "LU",
     "max arc size (LEGACY)");
 
@@ -558,11 +561,13 @@ param_set_max_auto_ashift(SYSCTL_HANDLER_ARGS)
 	return (0);
 }
 
-SYSCTL_PROC(_vfs_zfs, OID_AUTO, min_auto_ashift, CTLTYPE_U64 | CTLFLAG_RWTUN,
+SYSCTL_PROC(_vfs_zfs, OID_AUTO, min_auto_ashift,
+    CTLTYPE_U64 | CTLFLAG_RWTUN | CTLFLAG_MPSAFE,
     &zfs_vdev_min_auto_ashift, sizeof (zfs_vdev_min_auto_ashift),
     param_set_min_auto_ashift, "QU",
     "Min ashift used when creating new top-level vdev. (LEGACY)");
-SYSCTL_PROC(_vfs_zfs, OID_AUTO, max_auto_ashift, CTLTYPE_U64 | CTLFLAG_RWTUN,
+SYSCTL_PROC(_vfs_zfs, OID_AUTO, max_auto_ashift,
+    CTLTYPE_U64 | CTLFLAG_RWTUN | CTLFLAG_MPSAFE,
     &zfs_vdev_max_auto_ashift, sizeof (zfs_vdev_max_auto_ashift),
     param_set_max_auto_ashift, "QU",
     "Max ashift used when optimizing for logical -> physical sector size on "