Re: [PATCH 1/2] powerpc: remove cpu_online_cores_map function
From: Sachin Sant <hidden>
Date: 2021-11-05 13:10:22
On 05-Nov-2021, at 9:20 AM, Nicholas Piggin [off-list ref] wrote: This function builds the cores online map with on-stack cpumasks which can cause high stack usage with large NR_CPUS. It is not used in any performance sensitive paths, so instead just check for first thread sibling. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> ---
Tested-by: Sachin Sant <redacted> Thanks - Sachin
quoted hunk ↗ jump to hunk
arch/powerpc/include/asm/cputhreads.h | 33 ----------------------- arch/powerpc/platforms/powernv/idle.c | 10 +++---- arch/powerpc/platforms/powernv/opal-imc.c | 6 ++--- 3 files changed, 8 insertions(+), 41 deletions(-)diff --git a/arch/powerpc/include/asm/cputhreads.h b/arch/powerpc/include/asm/cputhreads.h index b167186aaee4..f26c430f3982 100644 --- a/arch/powerpc/include/asm/cputhreads.h +++ b/arch/powerpc/include/asm/cputhreads.h@@ -32,44 +32,11 @@ extern cpumask_t threads_core_mask;#define threads_core_mask (*get_cpu_mask(0)) #endif -/* cpu_thread_mask_to_cores - Return a cpumask of one per cores - * hit by the argument - * - * @threads: a cpumask of online threads - * - * This function returns a cpumask which will have one online cpu's - * bit set for each core that has at least one thread set in the argument. - * - * This can typically be used for things like IPI for tlb invalidations - * since those need to be done only once per core/TLB - */ -static inline cpumask_t cpu_thread_mask_to_cores(const struct cpumask *threads) -{ - cpumask_t tmp, res; - int i, cpu; - - cpumask_clear(&res); - for (i = 0; i < NR_CPUS; i += threads_per_core) { - cpumask_shift_left(&tmp, &threads_core_mask, i); - if (cpumask_intersects(threads, &tmp)) { - cpu = cpumask_next_and(-1, &tmp, cpu_online_mask); - if (cpu < nr_cpu_ids) - cpumask_set_cpu(cpu, &res); - } - } - return res; -} - static inline int cpu_nr_cores(void) { return nr_cpu_ids >> threads_shift; } -static inline cpumask_t cpu_online_cores_map(void) -{ - return cpu_thread_mask_to_cores(cpu_online_mask); -} - #ifdef CONFIG_SMP int cpu_core_index_of_thread(int cpu); int cpu_first_thread_of_core(int core);diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c index e3ffdc8e8567..70da314fd2d7 100644 --- a/arch/powerpc/platforms/powernv/idle.c +++ b/arch/powerpc/platforms/powernv/idle.c@@ -146,9 +146,13 @@ EXPORT_SYMBOL_GPL(pnv_get_supported_cpuidle_states);static void pnv_fastsleep_workaround_apply(void *info) { + int cpu = smp_processor_id(); int rc; int *err = info; + if (cpu_first_thread_sibling(cpu) != cpu) + return; + rc = opal_config_cpu_idle_state(OPAL_CONFIG_IDLE_FASTSLEEP, OPAL_CONFIG_IDLE_APPLY); if (rc)@@ -175,7 +179,6 @@ static ssize_t store_fastsleep_workaround_applyonce(struct device *dev,struct device_attribute *attr, const char *buf, size_t count) { - cpumask_t primary_thread_mask; int err; u8 val;@@ -200,10 +203,7 @@ static ssize_t store_fastsleep_workaround_applyonce(struct device *dev,power7_fastsleep_workaround_exit = false; cpus_read_lock(); - primary_thread_mask = cpu_online_cores_map(); - on_each_cpu_mask(&primary_thread_mask, - pnv_fastsleep_workaround_apply, - &err, 1); + on_each_cpu(pnv_fastsleep_workaround_apply, &err, 1); cpus_read_unlock(); if (err) { pr_err("fastsleep_workaround_applyonce change failed while running pnv_fastsleep_workaround_apply");diff --git a/arch/powerpc/platforms/powernv/opal-imc.c b/arch/powerpc/platforms/powernv/opal-imc.c index 05d3832019b9..3fea5da6d1b3 100644 --- a/arch/powerpc/platforms/powernv/opal-imc.c +++ b/arch/powerpc/platforms/powernv/opal-imc.c@@ -200,13 +200,13 @@ static void disable_nest_pmu_counters(void)static void disable_core_pmu_counters(void) { - cpumask_t cores_map; int cpu, rc; cpus_read_lock(); /* Disable the IMC Core functions */ - cores_map = cpu_online_cores_map(); - for_each_cpu(cpu, &cores_map) { + for_each_online_cpu(cpu) { + if (cpu_first_thread_sibling(cpu) != cpu) + continue; rc = opal_imc_counters_stop(OPAL_IMC_COUNTERS_CORE, get_hard_smp_processor_id(cpu)); if (rc) -- 2.23.0