x86/platform/uv/BAU: Disable BAU on single hub configurations (2fe9a5c6) · Commits · 戴 / test

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. Also, while at it, consolidate initialization error blocks and fix a memory leak. Signed-off-by:

Andrew Banman <abanman@hpe.com> Acked-by:

Russ Anderson <rja@hpe.com> Acked-by:

Mike Travis <mike.travis@hpe.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: tony.ernst@hpe.com Link: http://lkml.kernel.org/r/1500588351-78016-1-git-send-email-abanman@hpe.com [ Minor cleanups. ] Signed-off-by:

Ingo Molnar <mingo@kernel.org>

arch/x86/platform/uv/tlb_uv.c

+18 −5

Original line number	Diff line number	Diff line
		@@ -2221,13 +2221,17 @@ 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);
		@@ -2240,9 +2244,8 @@ 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;
		@@ -2268,6 +2271,16 @@ 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);

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