The BAU confers no benefit to a UV system running with only one hub/socket.
Permanently disable the BAU driver if there are less than two hubs online
to avoid BAU overhead. We have observed failed boots on single-socket UV4
systems caused by BAU that are avoided with this patch.
Version 2: Consolidate initialization error blocks with goto err_bau_disable
and free the per_cpu cpumasks to fix a memory leak.
Signed-off-by: Andrew Banman <aban...@hpe.com>
Acked-by: Russ Anderson <r...@hpe.com>
Acked-by: Mike Travis <mike.tra...@hpe.com>
---
arch/x86/platform/uv/tlb_uv.c | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c
index 2511a28..e4a51a6 100644
--- a/arch/x86/platform/uv/tlb_uv.c
+++ b/arch/x86/platform/uv/tlb_uv.c
@@ -2245,13 +2245,17 @@ static int __init uv_bau_init(void)
else if (is_uv1_hub())
ops = uv1_bau_ops;
+ nuvhubs = uv_num_possible_blades();
+ if (nuvhubs < 2) {
+ pr_crit("UV: BAU disabled - insufficient hub count\n");
+ goto err_bau_disable;
+ }
+
for_each_possible_cpu(cur_cpu) {
mask = &per_cpu(uv_flush_tlb_mask, cur_cpu);
zalloc_cpumask_var_node(mask, GFP_KERNEL, cpu_to_node(cur_cpu));
}
- nuvhubs = uv_num_possible_blades();
-
uv_base_pnode = 0x7fffffff;
for (uvhub = 0; uvhub < nuvhubs; uvhub++) {
cpus = uv_blade_nr_possible_cpus(uvhub);
@@ -2264,9 +2268,8 @@ static int __init uv_bau_init(void)
enable_timeouts();
if (init_per_cpu(nuvhubs, uv_base_pnode)) {
- set_bau_off();
- nobau_perm = 1;
- return 0;
+ pr_crit("UV: BAU disabled - per CPU init failed\n");
+ goto err_bau_disable;
}
vector = UV_BAU_MESSAGE;
@@ -2292,6 +2295,14 @@ static int __init uv_bau_init(void)
}
return 0;
+
+err_bau_disable:
+ for_each_possible_cpu(cur_cpu) {
+ free_cpumask_var(per_cpu(uv_flush_tlb_mask, cur_cpu));
+ }
+ set_bau_off();
+ nobau_perm = 1;
+ return -EINVAL;
}
core_initcall(uv_bau_init);
fs_initcall(uv_ptc_init);
--
1.8.2.1
