From 8f37961cf22304fb286c7604d3a7f6104dcc1283 Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Wed, 21 Sep 2016 12:19:03 -0700 Subject: [PATCH] sched/core, x86/topology: Fix NUMA in package topology bug Current code can call set_cpu_sibling_map() and invoke sched_set_topology() more than once (e.g. on CPU hot plug). When this happens after sched_init_smp() has been called, we lose the NUMA topology extension to sched_domain_topology in sched_init_numa(). This results in incorrect topology when the sched domain is rebuilt. This patch fixes the bug and issues warning if we call sched_set_topology() after sched_init_smp(). Signed-off-by: Tim Chen Signed-off-by: Srinivas Pandruvada Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: bp@suse.de Cc: jolsa@redhat.com Cc: rjw@rjwysocki.net Link: http://lkml.kernel.org/r/1474485552-141429-2-git-send-email-srinivas.pandruvada@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/smpboot.c | 46 ++++++++++++++++++++++++++++++---------------- kernel/sched/core.c | 3 +++ 2 files changed, 33 insertions(+), 16 deletions(-) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 4296beb..7137ec4 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -471,7 +471,7 @@ static bool match_die(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o) return false; } -static struct sched_domain_topology_level numa_inside_package_topology[] = { +static struct sched_domain_topology_level x86_numa_in_package_topology[] = { #ifdef CONFIG_SCHED_SMT { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) }, #endif @@ -480,22 +480,23 @@ static struct sched_domain_topology_level numa_inside_package_topology[] = { #endif { NULL, }, }; + +static struct sched_domain_topology_level x86_topology[] = { +#ifdef CONFIG_SCHED_SMT + { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) }, +#endif +#ifdef CONFIG_SCHED_MC + { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) }, +#endif + { cpu_cpu_mask, SD_INIT_NAME(DIE) }, + { NULL, }, +}; + /* - * set_sched_topology() sets the topology internal to a CPU. The - * NUMA topologies are layered on top of it to build the full - * system topology. - * - * If NUMA nodes are observed to occur within a CPU package, this - * function should be called. It forces the sched domain code to - * only use the SMT level for the CPU portion of the topology. - * This essentially falls back to relying on NUMA information - * from the SRAT table to describe the entire system topology - * (except for hyperthreads). + * Set if a package/die has multiple NUMA nodes inside. + * AMD Magny-Cours and Intel Cluster-on-Die have this. */ -static void primarily_use_numa_for_topology(void) -{ - set_sched_topology(numa_inside_package_topology); -} +static bool x86_has_numa_in_package; void set_cpu_sibling_map(int cpu) { @@ -558,7 +559,7 @@ void set_cpu_sibling_map(int cpu) c->booted_cores = cpu_data(i).booted_cores; } if (match_die(c, o) && !topology_same_node(c, o)) - primarily_use_numa_for_topology(); + x86_has_numa_in_package = true; } threads = cpumask_weight(topology_sibling_cpumask(cpu)); @@ -1304,6 +1305,16 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus) zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL); zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL); } + + /* + * Set 'default' x86 topology, this matches default_topology() in that + * it has NUMA nodes as a topology level. See also + * native_smp_cpus_done(). + * + * Must be done before set_cpus_sibling_map() is ran. + */ + set_sched_topology(x86_topology); + set_cpu_sibling_map(0); switch (smp_sanity_check(max_cpus)) { @@ -1370,6 +1381,9 @@ void __init native_smp_cpus_done(unsigned int max_cpus) { pr_debug("Boot done\n"); + if (x86_has_numa_in_package) + set_sched_topology(x86_numa_in_package_topology); + nmi_selftest(); impress_friends(); setup_ioapic_dest(); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 8bae0cd..af5d4d7 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6552,6 +6552,9 @@ static struct sched_domain_topology_level *sched_domain_topology = void set_sched_topology(struct sched_domain_topology_level *tl) { + if (WARN_ON_ONCE(sched_smp_initialized)) + return; + sched_domain_topology = tl; } -- 2.7.4