libgomp: call numa_available first when using libnuma

The documentation requires that numa_available() is called and only
when successful, other libnuma function may be called. Internally,
it does a syscall to get_mempolicy with flag=0 (which would return
the default policy if mode were not NULL). If this returns -1 (and
not 0) and errno == ENOSYS, the Linux kernel does not have the
get_mempolicy syscall function; if so, numa_available() returns -1
(otherwise: 0).

libgomp/

	PR libgomp/111024
	* allocator.c (gomp_init_libnuma): Call numa_available; if
	not available or not returning 0, disable libnuma usage.

1 files changed, 11 insertions, 0 deletions

diff --git a/libgomp/allocator.c b/libgomp/allocator.c
index 90f2dcb..b4e50e2 100644
--- a/libgomp/allocator.c
+++ b/libgomp/allocator.c
@@ -118,6 +118,17 @@ gomp_init_libnuma (void)
 	dlclose (handle);
       return;
     }
+  if (handle)
+    {
+      int (*numa_available) (void);
+      numa_available
+	= (__typeof (numa_available)) dlsym (handle, "numa_available");
+      if (!numa_available || numa_available () != 0)
+	{
+	  dlclose (handle);
+	  handle = NULL;
+	}
+    }
   if (!handle)
     {
       __atomic_store_n (&libnuma_data, data, MEMMODEL_RELEASE);