[Libguestfs] [PATCH common] mlutils: Simple wrapper around sysconf (_SC_NPROCESSORS_ONLN).
---
mlutils/unix_utils-c.c | 15 +++++++++++++++
mlutils/unix_utils.ml | 5 +++++
mlutils/unix_utils.mli | 9 +++++++++
3 files changed, 29 insertions(+)
diff --git a/mlutils/unix_utils-c.c b/mlutils/unix_utils-c.c
index 3309961..8acf039 100644
--- a/mlutils/unix_utils-c.c
+++ b/mlutils/unix_utils-c.c
@@ -77,6 +77,7 @@ extern value guestfs_int_mllib_mkdtemp (value val_pattern);
extern value guestfs_int_mllib_realpath (value pathv);
extern value guestfs_int_mllib_statvfs_statvfs (value pathv);
extern value guestfs_int_mllib_statvfs_is_network_filesystem (value pathv);
+extern value guestfs_int_mllib_sysconf_nr_processors_online (value unitv);
/* NB: This is a "noalloc" call. */
value
@@ -368,3 +369,17 @@ guestfs_int_mllib_statvfs_is_network_filesystem (value pathv)
return Val_bool (0);
#endif
}
+
+/* NB: This is a "noalloc" call. */
+value
+guestfs_int_mllib_sysconf_nr_processors_online (value unitv)
+{
+#ifdef _SC_NPROCESSORS_ONLN
+ long n;
+
+ n = sysconf (_SC_NPROCESSORS_ONLN);
+ if (n > 0) return Val_int (n);
+#endif
+ /* Return a safe value so that callers don't need to deal with errors. */
+ return Val_int (1);
+}
diff --git a/mlutils/unix_utils.ml b/mlutils/unix_utils.ml
index 52eb824..2bdda12 100644
--- a/mlutils/unix_utils.ml
+++ b/mlutils/unix_utils.ml
@@ -84,3 +84,8 @@ module StatVFS = struct
external is_network_filesystem : string -> bool =
"guestfs_int_mllib_statvfs_is_network_filesystem" "noalloc"
end
+
+module Sysconf = struct
+ external nr_processors_online : unit -> int =
+ "guestfs_int_mllib_sysconf_nr_processors_online" "noalloc"
+end
diff --git a/mlutils/unix_utils.mli b/mlutils/unix_utils.mli
index 4fcea4a..aead4df 100644
--- a/mlutils/unix_utils.mli
+++ b/mlutils/unix_utils.mli
@@ -121,3 +121,12 @@ module StatVFS : sig
(** [is_network_filesystem path] returns true if [path] is located on
a network filesystem such as NFS or CIFS. *)
end
+
+module Sysconf : sig
+ val nr_processors_online : unit -> int
+ (** [nr_processors_online ()] returns the number of processors
+ currently online, from [sysconf (_SC_NPROCESSORS_ONLN)].
+
+ Note this never fails. In case we cannot get the number of
+ cores it returns 1. *)
+end
--
2.27.0