[IA64-SGI] - Reduce overhead of reading sn_topology
Jack Steiner [Sat, 22 Apr 2006 14:37:19 +0000 (09:37 -0500)]
MPI programs using certain debug options have a long
startup time. This was traced to a "vmalloc/vfree" in
the code that reads /proc/sgi_sn/sn_topology. On large
systems, vfree requires an IPI to all cpus to do TLB
purging.

Replace the vmalloc/vfree with kmalloc/kfree. Although
the size of the structure being allocated is unknown, it
will not not exceed 96 bytes.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/sn/kernel/sn2/sn_hwperf.c

index 7ec65bc..739c948 100644 (file)
@@ -493,7 +493,7 @@ static int sn_topology_show(struct seq_file *s, void *d)
                 * numalink ports
                 */
                sz = obj->ports * sizeof(struct sn_hwperf_port_info);
-               if ((ptdata = vmalloc(sz)) == NULL)
+               if ((ptdata = kmalloc(sz, GFP_KERNEL)) == NULL)
                        return -ENOMEM;
                e = ia64_sn_hwperf_op(sn_hwperf_master_nasid,
                                      SN_HWPERF_ENUM_PORTS, obj->id, sz,
@@ -541,7 +541,7 @@ static int sn_topology_show(struct seq_file *s, void *d)
                                (SN_HWPERF_IS_NL3ROUTER(obj) ||
                                SN_HWPERF_IS_NL3ROUTER(p)) ?  "LLP3" : "LLP4");
                }
-               vfree(ptdata);
+               kfree(ptdata);
        }
 
        return 0;