From: Alexey Dobriyan <adobriyan@xxxxxxxxx> Subject: treewide: make "nr_cpu_ids" unsigned First, number of CPUs can't be negative number. Second, different signnnedness leads to suboptimal code in the following cases: 1) kmalloc(nr_cpu_ids * sizeof(X)); "int" has to be sign extended to size_t. 2) while (loff_t *pos < nr_cpu_ids) MOVSXD is 1 byte longed than the same MOV. Other cases exist as well. Basically compiler is told that nr_cpu_ids can't be negative which can't be deduced if it is "int". Code savings on allyesconfig kernel: -3KB add/remove: 0/0 grow/shrink: 25/264 up/down: 261/-3631 (-3370) function old new delta coretemp_cpu_online 450 512 +62 rcu_init_one 1234 1272 +38 pci_device_probe 374 399 +25 ... pgdat_reclaimable_pages 628 556 -72 select_fallback_rq 446 369 -77 task_numa_find_cpu 1923 1807 -116 Link: http://lkml.kernel.org/r/20170819114959.GA30580@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/arm64/kernel/smp.c | 2 +- arch/powerpc/kernel/paca.c | 2 +- arch/powerpc/kernel/setup-common.c | 2 +- arch/powerpc/sysdev/xive/native.c | 4 ++-- arch/tile/kernel/setup.c | 2 +- arch/x86/kernel/apic/apic.c | 2 +- arch/x86/kernel/setup_percpu.c | 2 +- arch/x86/kernel/smpboot.c | 2 +- drivers/base/cpu.c | 4 ++-- drivers/scsi/scsi_debug.c | 2 +- include/linux/cpumask.h | 6 +++--- kernel/rcu/tree.c | 2 +- kernel/rcu/tree_plugin.h | 2 +- kernel/sched/topology.c | 2 +- kernel/smp.c | 2 +- kernel/trace/trace_functions_graph.c | 2 +- mm/slub.c | 2 +- 17 files changed, 21 insertions(+), 21 deletions(-) diff -puN arch/arm64/kernel/smp.c~make-nr_cpu_ids-unsigned arch/arm64/kernel/smp.c --- a/arch/arm64/kernel/smp.c~make-nr_cpu_ids-unsigned +++ a/arch/arm64/kernel/smp.c @@ -690,7 +690,7 @@ void __init smp_init_cpus(void) acpi_parse_gic_cpu_interface, 0); if (cpu_count > nr_cpu_ids) - pr_warn("Number of cores (%d) exceeds configured maximum of %d - clipping\n", + pr_warn("Number of cores (%d) exceeds configured maximum of %u - clipping\n", cpu_count, nr_cpu_ids); if (!bootcpu_valid) { diff -puN arch/powerpc/kernel/paca.c~make-nr_cpu_ids-unsigned arch/powerpc/kernel/paca.c --- a/arch/powerpc/kernel/paca.c~make-nr_cpu_ids-unsigned +++ a/arch/powerpc/kernel/paca.c @@ -224,7 +224,7 @@ void __init allocate_pacas(void) paca = __va(memblock_alloc_base(paca_size, PAGE_SIZE, limit)); memset(paca, 0, paca_size); - printk(KERN_DEBUG "Allocated %u bytes for %d pacas at %p\n", + printk(KERN_DEBUG "Allocated %u bytes for %u pacas at %p\n", paca_size, nr_cpu_ids, paca); allocate_lppacas(nr_cpu_ids, limit); diff -puN arch/powerpc/kernel/setup-common.c~make-nr_cpu_ids-unsigned arch/powerpc/kernel/setup-common.c --- a/arch/powerpc/kernel/setup-common.c~make-nr_cpu_ids-unsigned +++ a/arch/powerpc/kernel/setup-common.c @@ -551,7 +551,7 @@ void __init smp_setup_cpu_maps(void) if (maxcpus > nr_cpu_ids) { printk(KERN_WARNING "Partition configured for %d cpus, " - "operating system maximum is %d.\n", + "operating system maximum is %u.\n", maxcpus, nr_cpu_ids); maxcpus = nr_cpu_ids; } else diff -puN arch/powerpc/sysdev/xive/native.c~make-nr_cpu_ids-unsigned arch/powerpc/sysdev/xive/native.c --- a/arch/powerpc/sysdev/xive/native.c~make-nr_cpu_ids-unsigned +++ a/arch/powerpc/sysdev/xive/native.c @@ -511,13 +511,13 @@ static bool xive_parse_provisioning(stru static void xive_native_setup_pools(void) { /* Allocate a pool big enough */ - pr_debug("XIVE: Allocating VP block for pool size %d\n", nr_cpu_ids); + pr_debug("XIVE: Allocating VP block for pool size %u\n", nr_cpu_ids); xive_pool_vps = xive_native_alloc_vp_block(nr_cpu_ids); if (WARN_ON(xive_pool_vps == XIVE_INVALID_VP)) pr_err("XIVE: Failed to allocate pool VP, KVM might not function\n"); - pr_debug("XIVE: Pool VPs allocated at 0x%x for %d max CPUs\n", + pr_debug("XIVE: Pool VPs allocated at 0x%x for %u max CPUs\n", xive_pool_vps, nr_cpu_ids); } diff -puN arch/tile/kernel/setup.c~make-nr_cpu_ids-unsigned arch/tile/kernel/setup.c --- a/arch/tile/kernel/setup.c~make-nr_cpu_ids-unsigned +++ a/arch/tile/kernel/setup.c @@ -1200,7 +1200,7 @@ static void __init validate_hv(void) * We use a struct cpumask for this, so it must be big enough. */ if ((smp_height * smp_width) > nr_cpu_ids) - early_panic("Hypervisor %d x %d grid too big for Linux NR_CPUS %d\n", + early_panic("Hypervisor %d x %d grid too big for Linux NR_CPUS %u\n", smp_height, smp_width, nr_cpu_ids); #endif diff -puN arch/x86/kernel/apic/apic.c~make-nr_cpu_ids-unsigned arch/x86/kernel/apic/apic.c --- a/arch/x86/kernel/apic/apic.c~make-nr_cpu_ids-unsigned +++ a/arch/x86/kernel/apic/apic.c @@ -2097,7 +2097,7 @@ static int allocate_logical_cpuid(int ap /* Allocate a new cpuid. */ if (nr_logical_cpuids >= nr_cpu_ids) { - WARN_ONCE(1, "APIC: NR_CPUS/possible_cpus limit of %i reached. " + WARN_ONCE(1, "APIC: NR_CPUS/possible_cpus limit of %u reached. " "Processor %d/0x%x and the rest are ignored.\n", nr_cpu_ids, nr_logical_cpuids, apicid); return -EINVAL; diff -puN arch/x86/kernel/setup_percpu.c~make-nr_cpu_ids-unsigned arch/x86/kernel/setup_percpu.c --- a/arch/x86/kernel/setup_percpu.c~make-nr_cpu_ids-unsigned +++ a/arch/x86/kernel/setup_percpu.c @@ -168,7 +168,7 @@ void __init setup_per_cpu_areas(void) unsigned long delta; int rc; - pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%d nr_node_ids:%d\n", + pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%u nr_node_ids:%d\n", NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids); /* diff -puN arch/x86/kernel/smpboot.c~make-nr_cpu_ids-unsigned arch/x86/kernel/smpboot.c --- a/arch/x86/kernel/smpboot.c~make-nr_cpu_ids-unsigned +++ a/arch/x86/kernel/smpboot.c @@ -1461,7 +1461,7 @@ __init void prefill_possible_map(void) /* nr_cpu_ids could be reduced via nr_cpus= */ if (possible > nr_cpu_ids) { - pr_warn("%d Processors exceeds NR_CPUS limit of %d\n", + pr_warn("%d Processors exceeds NR_CPUS limit of %u\n", possible, nr_cpu_ids); possible = nr_cpu_ids; } diff -puN drivers/base/cpu.c~make-nr_cpu_ids-unsigned drivers/base/cpu.c --- a/drivers/base/cpu.c~make-nr_cpu_ids-unsigned +++ a/drivers/base/cpu.c @@ -256,9 +256,9 @@ static ssize_t print_cpus_offline(struct buf[n++] = ','; if (nr_cpu_ids == total_cpus-1) - n += snprintf(&buf[n], len - n, "%d", nr_cpu_ids); + n += snprintf(&buf[n], len - n, "%u", nr_cpu_ids); else - n += snprintf(&buf[n], len - n, "%d-%d", + n += snprintf(&buf[n], len - n, "%u-%d", nr_cpu_ids, total_cpus-1); } diff -puN drivers/scsi/scsi_debug.c~make-nr_cpu_ids-unsigned drivers/scsi/scsi_debug.c --- a/drivers/scsi/scsi_debug.c~make-nr_cpu_ids-unsigned +++ a/drivers/scsi/scsi_debug.c @@ -5465,7 +5465,7 @@ static int sdebug_driver_probe(struct de return error; } if (submit_queues > nr_cpu_ids) { - pr_warn("%s: trim submit_queues (was %d) to nr_cpu_ids=%d\n", + pr_warn("%s: trim submit_queues (was %d) to nr_cpu_ids=%u\n", my_name, submit_queues, nr_cpu_ids); submit_queues = nr_cpu_ids; } diff -puN include/linux/cpumask.h~make-nr_cpu_ids-unsigned include/linux/cpumask.h --- a/include/linux/cpumask.h~make-nr_cpu_ids-unsigned +++ a/include/linux/cpumask.h @@ -32,15 +32,15 @@ typedef struct cpumask { DECLARE_BITMAP( #define cpumask_pr_args(maskp) nr_cpu_ids, cpumask_bits(maskp) #if NR_CPUS == 1 -#define nr_cpu_ids 1 +#define nr_cpu_ids 1U #else -extern int nr_cpu_ids; +extern unsigned int nr_cpu_ids; #endif #ifdef CONFIG_CPUMASK_OFFSTACK /* Assuming NR_CPUS is huge, a runtime limit is more efficient. Also, * not all bits may be allocated. */ -#define nr_cpumask_bits ((unsigned int)nr_cpu_ids) +#define nr_cpumask_bits nr_cpu_ids #else #define nr_cpumask_bits ((unsigned int)NR_CPUS) #endif diff -puN kernel/rcu/tree.c~make-nr_cpu_ids-unsigned kernel/rcu/tree.c --- a/kernel/rcu/tree.c~make-nr_cpu_ids-unsigned +++ a/kernel/rcu/tree.c @@ -4091,7 +4091,7 @@ static void __init rcu_init_geometry(voi if (rcu_fanout_leaf == RCU_FANOUT_LEAF && nr_cpu_ids == NR_CPUS) return; - pr_info("RCU: Adjusting geometry for rcu_fanout_leaf=%d, nr_cpu_ids=%d\n", + pr_info("RCU: Adjusting geometry for rcu_fanout_leaf=%d, nr_cpu_ids=%u\n", rcu_fanout_leaf, nr_cpu_ids); /* diff -puN kernel/rcu/tree_plugin.h~make-nr_cpu_ids-unsigned kernel/rcu/tree_plugin.h --- a/kernel/rcu/tree_plugin.h~make-nr_cpu_ids-unsigned +++ a/kernel/rcu/tree_plugin.h @@ -89,7 +89,7 @@ static void __init rcu_bootup_announce_o if (rcu_fanout_leaf != RCU_FANOUT_LEAF) pr_info("\tBoot-time adjustment of leaf fanout to %d.\n", rcu_fanout_leaf); if (nr_cpu_ids != NR_CPUS) - pr_info("\tRCU restricting CPUs from NR_CPUS=%d to nr_cpu_ids=%d.\n", NR_CPUS, nr_cpu_ids); + pr_info("\tRCU restricting CPUs from NR_CPUS=%d to nr_cpu_ids=%u.\n", NR_CPUS, nr_cpu_ids); #ifdef CONFIG_RCU_BOOST pr_info("\tRCU priority boosting: priority %d delay %d ms.\n", kthread_prio, CONFIG_RCU_BOOST_DELAY); #endif diff -puN kernel/sched/topology.c~make-nr_cpu_ids-unsigned kernel/sched/topology.c --- a/kernel/sched/topology.c~make-nr_cpu_ids-unsigned +++ a/kernel/sched/topology.c @@ -473,7 +473,7 @@ static int __init isolated_cpu_setup(cha alloc_bootmem_cpumask_var(&cpu_isolated_map); ret = cpulist_parse(str, cpu_isolated_map); if (ret) { - pr_err("sched: Error, all isolcpus= values must be between 0 and %d\n", nr_cpu_ids); + pr_err("sched: Error, all isolcpus= values must be between 0 and %u\n", nr_cpu_ids); return 0; } return 1; diff -puN kernel/smp.c~make-nr_cpu_ids-unsigned kernel/smp.c --- a/kernel/smp.c~make-nr_cpu_ids-unsigned +++ a/kernel/smp.c @@ -550,7 +550,7 @@ static int __init maxcpus(char *str) early_param("maxcpus", maxcpus); /* Setup number of possible processor ids */ -int nr_cpu_ids __read_mostly = NR_CPUS; +unsigned int nr_cpu_ids __read_mostly = NR_CPUS; EXPORT_SYMBOL(nr_cpu_ids); /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */ diff -puN kernel/trace/trace_functions_graph.c~make-nr_cpu_ids-unsigned kernel/trace/trace_functions_graph.c --- a/kernel/trace/trace_functions_graph.c~make-nr_cpu_ids-unsigned +++ a/kernel/trace/trace_functions_graph.c @@ -1543,7 +1543,7 @@ fs_initcall(init_graph_tracefs); static __init int init_graph_trace(void) { - max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1); + max_bytes_for_cpu = snprintf(NULL, 0, "%u", nr_cpu_ids - 1); if (!register_trace_event(&graph_trace_entry_event)) { pr_warn("Warning: could not register graph trace events\n"); diff -puN mm/slub.c~make-nr_cpu_ids-unsigned mm/slub.c --- a/mm/slub.c~make-nr_cpu_ids-unsigned +++ a/mm/slub.c @@ -4232,7 +4232,7 @@ void __init kmem_cache_init(void) cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL, slub_cpu_dead); - pr_info("SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d, CPUs=%d, Nodes=%d\n", + pr_info("SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d, CPUs=%u, Nodes=%d\n", cache_line_size(), slub_min_order, slub_max_order, slub_min_objects, nr_cpu_ids, nr_node_ids); _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
