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Commit 99d86705 authored by Vaidyanathan Srinivasan's avatar Vaidyanathan Srinivasan Committed by Benjamin Herrenschmidt
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powerpc: Cleanup APIs for cpu/thread/core mappings 



These APIs take logical cpu number as input
Change cpu_first_thread_in_core() to cpu_first_thread_sibling()
Change cpu_last_thread_in_core() to cpu_last_thread_sibling()

These APIs convert core number (index) to logical cpu/thread numbers
Add cpu_first_thread_of_core(int core)
Changed cpu_thread_to_core() to cpu_core_index_of_thread(int cpu)

The goal is to make 'threads_per_core' accessible to the
pseries_energy module.  Instead of making an API to read
threads_per_core, this is a higher level wrapper function to
convert from logical cpu number to core number.

The current APIs cpu_first_thread_in_core() and
cpu_last_thread_in_core() returns logical CPU number while
cpu_thread_to_core() returns core number or index which is
not a logical CPU number.  The new APIs are now clearly named to
distinguish 'core number' versus first and last 'logical cpu
number' in that core.

The new APIs cpu_{first,last}_thread_sibling() work on
logical cpu numbers.  While cpu_first_thread_of_core() and
cpu_core_index_of_thread() work on core index.

Example usage:  (4 threads per core system)

cpu_first_thread_sibling(5) = 4
cpu_last_thread_sibling(5) = 7
cpu_core_index_of_thread(5) = 1
cpu_first_thread_of_core(1) = 4

cpu_core_index_of_thread() is used in cpu_to_drc_index() in the
module and cpu_first_thread_of_core() is used in
drc_index_to_cpu() in the module.

Make API changes to few callers.  Export symbols for use in modules.

Signed-off-by: default avatarVaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 787d44ca

arch/powerpc/include/asm/cputhreads.h

+9 −6
Original line number Diff line number Diff line
@@ -61,22 +61,25 @@ static inline cpumask_t cpu_online_cores_map(void) 
	return cpu_thread_mask_to_cores(cpu_online_map);

}



static inline int cpu_thread_to_core(int cpu)

{

	return cpu >> threads_shift;

}

#ifdef CONFIG_SMP

int cpu_core_index_of_thread(int cpu);

int cpu_first_thread_of_core(int core);

#else

static inline int cpu_core_index_of_thread(int cpu) { return cpu; }

static inline int cpu_first_thread_of_core(int core) { return core; }

#endif



static inline int cpu_thread_in_core(int cpu)

{

	return cpu & (threads_per_core - 1);

}



static inline int cpu_first_thread_in_core(int cpu)

static inline int cpu_first_thread_sibling(int cpu)

{

	return cpu & ~(threads_per_core - 1);

}



static inline int cpu_last_thread_in_core(int cpu)

static inline int cpu_last_thread_sibling(int cpu)

{

	return cpu | (threads_per_core - 1);

}

arch/powerpc/kernel/smp.c

+16 −3
Original line number Diff line number Diff line
@@ -466,7 +466,20 @@ int cpu_to_core_id(int cpu) 
	return id;

}



/* Must be called when no change can occur to cpu_present_mask,

/* Helper routines for cpu to core mapping */

int cpu_core_index_of_thread(int cpu)

{

	return cpu >> threads_shift;

}

EXPORT_SYMBOL_GPL(cpu_core_index_of_thread);



int cpu_first_thread_of_core(int core)

{

	return core << threads_shift;

}

EXPORT_SYMBOL_GPL(cpu_first_thread_of_core);



/* Must be called when no change can occur to cpu_present_map,

 * i.e. during cpu online or offline.

 */

static struct device_node *cpu_to_l2cache(int cpu)
@@ -514,7 +527,7 @@ int __devinit start_secondary(void *unused) 
	notify_cpu_starting(cpu);

	set_cpu_online(cpu, true);

	/* Update sibling maps */

	base = cpu_first_thread_in_core(cpu);

	base = cpu_first_thread_sibling(cpu);

	for (i = 0; i < threads_per_core; i++) {

		if (cpu_is_offline(base + i))

			continue;
@@ -600,7 +613,7 @@ int __cpu_disable(void) 
		return err;



	/* Update sibling maps */

	base = cpu_first_thread_in_core(cpu);

	base = cpu_first_thread_sibling(cpu);

	for (i = 0; i < threads_per_core; i++) {

		cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i));

		cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu));

arch/powerpc/mm/mmu_context_nohash.c

+6 −6
Original line number Diff line number Diff line
@@ -111,8 +111,8 @@ static unsigned int steal_context_smp(unsigned int id) 
		 * a core map instead but this will do for now.

		 */

		for_each_cpu(cpu, mm_cpumask(mm)) {

			for (i = cpu_first_thread_in_core(cpu);

			     i <= cpu_last_thread_in_core(cpu); i++)

			for (i = cpu_first_thread_sibling(cpu);

			     i <= cpu_last_thread_sibling(cpu); i++)

				__set_bit(id, stale_map[i]);

			cpu = i - 1;

		}
@@ -264,14 +264,14 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next) 
	 */

	if (test_bit(id, stale_map[cpu])) {

		pr_hardcont(" | stale flush %d [%d..%d]",

			    id, cpu_first_thread_in_core(cpu),

			    cpu_last_thread_in_core(cpu));

			    id, cpu_first_thread_sibling(cpu),

			    cpu_last_thread_sibling(cpu));



		local_flush_tlb_mm(next);



		/* XXX This clear should ultimately be part of local_flush_tlb_mm */

		for (i = cpu_first_thread_in_core(cpu);

		     i <= cpu_last_thread_in_core(cpu); i++) {

		for (i = cpu_first_thread_sibling(cpu);

		     i <= cpu_last_thread_sibling(cpu); i++) {

			__clear_bit(id, stale_map[i]);

		}

	}