Commit b350111b authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc: remove cpu_online_cores_map function 



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: default avatarNicholas Piggin <npiggin@gmail.com>
Tested-by: default avatarSachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211105035042.1398309-1-npiggin@gmail.com
parent af3fdce4

arch/powerpc/include/asm/cputhreads.h

+0 −33
Original line number Diff line number Diff line
@@ -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);

arch/powerpc/platforms/powernv/idle.c

+5 −5
Original line number Diff line number Diff line
@@ -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");

arch/powerpc/platforms/powernv/opal-imc.c

+3 −3
Original line number Diff line number Diff line
@@ -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)