From: Michael Neuling <mi...@neuling.org>
"cpufreq: powernv: Remove cpu_to_chip_id() from hot-path" introduced
'core_to_chip_map' array to cache the chip-id of all cores. Replace
this with per_cpu variable that stores the pointer to the chip-array.
This removes the linear lookup and provides a neater and simpler
solution.
Signed-off-by: Michael Neuling <mi...@neuling.org>
Tested-by: Shilpasri G Bhat <shilpa.b...@linux.vnet.ibm.com>
---
- Rebased the patch on top of linux-pm/linux-next
- nr_chips is defined static, so it will be initialized to zero
- Moved the initialization of the per_cpu variable after 'chips' is
allocated
- Removed 'core_to_chip_map'
drivers/cpufreq/powernv-cpufreq.c | 50 +++++++++++++--------------------------
1 file changed, 17 insertions(+), 33 deletions(-)
diff --git a/drivers/cpufreq/powernv-cpufreq.c
b/drivers/cpufreq/powernv-cpufreq.c
index 50bf120..a00bcc2 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -44,7 +44,6 @@
static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
static bool rebooting, throttled, occ_reset;
-static unsigned int *core_to_chip_map;
static const char * const throttle_reason[] = {
"No throttling",
@@ -65,6 +64,7 @@ static struct chip {
} *chips;
static int nr_chips;
+static DEFINE_PER_CPU(struct chip *, chip_info);
/*
* Note: The set of pstates consists of contiguous integers, the
@@ -324,34 +324,31 @@ static inline unsigned int get_nominal_index(void)
static void powernv_cpufreq_throttle_check(void *data)
{
+ struct chip *chip;
unsigned int cpu = smp_processor_id();
- unsigned int chip_id = core_to_chip_map[cpu_core_index_of_thread(cpu)];
unsigned long pmsr;
- int pmsr_pmax, i;
+ int pmsr_pmax;
pmsr = get_pmspr(SPRN_PMSR);
-
- for (i = 0; i < nr_chips; i++)
- if (chips[i].id == chip_id)
- break;
+ chip = this_cpu_read(chip_info);
/* Check for Pmax Capping */
pmsr_pmax = (s8)PMSR_MAX(pmsr);
if (pmsr_pmax != powernv_pstate_info.max) {
- if (chips[i].throttled)
+ if (chip->throttled)
goto next;
- chips[i].throttled = true;
+ chip->throttled = true;
if (pmsr_pmax < powernv_pstate_info.nominal)
pr_warn_once("CPU %d on Chip %u has Pmax reduced below
nominal frequency (%d < %d)\n",
- cpu, chips[i].id, pmsr_pmax,
+ cpu, chip->id, pmsr_pmax,
powernv_pstate_info.nominal);
- trace_powernv_throttle(chips[i].id,
- throttle_reason[chips[i].throttle_reason],
+ trace_powernv_throttle(chip->id,
+ throttle_reason[chip->throttle_reason],
pmsr_pmax);
- } else if (chips[i].throttled) {
- chips[i].throttled = false;
- trace_powernv_throttle(chips[i].id,
- throttle_reason[chips[i].throttle_reason],
+ } else if (chip->throttled) {
+ chip->throttled = false;
+ trace_powernv_throttle(chip->id,
+ throttle_reason[chip->throttle_reason],
pmsr_pmax);
}
@@ -558,47 +555,34 @@ static int init_chip_info(void)
unsigned int chip[256];
unsigned int cpu, i;
unsigned int prev_chip_id = UINT_MAX;
- cpumask_t cpu_mask;
- int ret = -ENOMEM;
-
- core_to_chip_map = kcalloc(cpu_nr_cores(), sizeof(unsigned int),
- GFP_KERNEL);
- if (!core_to_chip_map)
- goto out;
- cpumask_copy(&cpu_mask, cpu_possible_mask);
- for_each_cpu(cpu, &cpu_mask) {
+ for_each_possible_cpu(cpu) {
unsigned int id = cpu_to_chip_id(cpu);
if (prev_chip_id != id) {
prev_chip_id = id;
chip[nr_chips++] = id;
}
- core_to_chip_map[cpu_core_index_of_thread(cpu)] = id;
- cpumask_andnot(&cpu_mask, &cpu_mask, cpu_sibling_mask(cpu));
}
chips = kcalloc(nr_chips, sizeof(struct chip), GFP_KERNEL);
if (!chips)
- goto free_chip_map;
+ return -ENOMEM;
for (i = 0; i < nr_chips; i++) {
chips[i].id = chip[i];
cpumask_copy(&chips[i].mask, cpumask_of_node(chip[i]));
INIT_WORK(&chips[i].throttle, powernv_cpufreq_work_fn);
+ for_each_cpu(cpu, &chips[i].mask)
+ per_cpu(chip_info, cpu) = &chips[i];
}
return 0;
-free_chip_map:
- kfree(core_to_chip_map);
-out:
- return ret;
}
static inline void clean_chip_info(void)
{
kfree(chips);
- kfree(core_to_chip_map);
}
static inline void unregister_all_notifiers(void)
--
1.9.3
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