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Sebastian Andrzej SiewiorIngo Molnar
Sebastian Andrzej Siewior
authored and
Ingo Molnar
committed
profile: Convert to hotplug state machine
Install the callbacks via the state machine and let the core invoke the callbacks on the already online CPUs. A lot of code is removed because the for-loop is used and create_hash_tables() is removed since its purpose is covered by the startup / teardown hooks. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153337.649867675@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
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-116
lines changed

2 files changed

+66
-116
lines changed

‎include/linux/cpuhotplug.h

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -16,6 +16,7 @@ enum cpuhp_state {
1616
CPUHP_X86_APB_DEAD,
1717
CPUHP_WORKQUEUE_PREP,
1818
CPUHP_HRTIMERS_PREPARE,
19+
CPUHP_PROFILE_PREPARE,
1920
CPUHP_TIMERS_DEAD,
2021
CPUHP_NOTIFY_PREPARE,
2122
CPUHP_BRINGUP_CPU,

‎kernel/profile.c

Lines changed: 65 additions & 116 deletions
Original file line numberDiff line numberDiff line change
@@ -328,68 +328,57 @@ static void do_profile_hits(int type, void *__pc, unsigned int nr_hits)
328328
put_cpu();
329329
}
330330

331-
static int profile_cpu_callback(struct notifier_block *info,
332-
unsigned long action, void *__cpu)
331+
static int profile_dead_cpu(unsigned int cpu)
333332
{
334-
int node, cpu = (unsigned long)__cpu;
335333
struct page *page;
334+
int i;
336335

337-
switch (action) {
338-
case CPU_UP_PREPARE:
339-
case CPU_UP_PREPARE_FROZEN:
340-
node = cpu_to_mem(cpu);
341-
per_cpu(cpu_profile_flip, cpu) = 0;
342-
if (!per_cpu(cpu_profile_hits, cpu)[1]) {
343-
page = __alloc_pages_node(node,
344-
GFP_KERNEL | __GFP_ZERO,
345-
0);
346-
if (!page)
347-
return notifier_from_errno(-ENOMEM);
348-
per_cpu(cpu_profile_hits, cpu)[1] = page_address(page);
349-
}
350-
if (!per_cpu(cpu_profile_hits, cpu)[0]) {
351-
page = __alloc_pages_node(node,
352-
GFP_KERNEL | __GFP_ZERO,
353-
0);
354-
if (!page)
355-
goto out_free;
356-
per_cpu(cpu_profile_hits, cpu)[0] = page_address(page);
357-
}
358-
break;
359-
out_free:
360-
page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
361-
per_cpu(cpu_profile_hits, cpu)[1] = NULL;
362-
__free_page(page);
363-
return notifier_from_errno(-ENOMEM);
364-
case CPU_ONLINE:
365-
case CPU_ONLINE_FROZEN:
366-
if (prof_cpu_mask != NULL)
367-
cpumask_set_cpu(cpu, prof_cpu_mask);
368-
break;
369-
case CPU_UP_CANCELED:
370-
case CPU_UP_CANCELED_FROZEN:
371-
case CPU_DEAD:
372-
case CPU_DEAD_FROZEN:
373-
if (prof_cpu_mask != NULL)
374-
cpumask_clear_cpu(cpu, prof_cpu_mask);
375-
if (per_cpu(cpu_profile_hits, cpu)[0]) {
376-
page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
377-
per_cpu(cpu_profile_hits, cpu)[0] = NULL;
336+
if (prof_cpu_mask != NULL)
337+
cpumask_clear_cpu(cpu, prof_cpu_mask);
338+
339+
for (i = 0; i < 2; i++) {
340+
if (per_cpu(cpu_profile_hits, cpu)[i]) {
341+
page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[i]);
342+
per_cpu(cpu_profile_hits, cpu)[i] = NULL;
378343
__free_page(page);
379344
}
380-
if (per_cpu(cpu_profile_hits, cpu)[1]) {
381-
page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
382-
per_cpu(cpu_profile_hits, cpu)[1] = NULL;
383-
__free_page(page);
345+
}
346+
return 0;
347+
}
348+
349+
static int profile_prepare_cpu(unsigned int cpu)
350+
{
351+
int i, node = cpu_to_mem(cpu);
352+
struct page *page;
353+
354+
per_cpu(cpu_profile_flip, cpu) = 0;
355+
356+
for (i = 0; i < 2; i++) {
357+
if (per_cpu(cpu_profile_hits, cpu)[i])
358+
continue;
359+
360+
page = __alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
361+
if (!page) {
362+
profile_dead_cpu(cpu);
363+
return -ENOMEM;
384364
}
385-
break;
365+
per_cpu(cpu_profile_hits, cpu)[i] = page_address(page);
366+
386367
}
387-
return NOTIFY_OK;
368+
return 0;
369+
}
370+
371+
static int profile_online_cpu(unsigned int cpu)
372+
{
373+
if (prof_cpu_mask != NULL)
374+
cpumask_set_cpu(cpu, prof_cpu_mask);
375+
376+
return 0;
388377
}
378+
389379
#else /* !CONFIG_SMP */
390380
#define profile_flip_buffers() do { } while (0)
391381
#define profile_discard_flip_buffers() do { } while (0)
392-
#define profile_cpu_callback NULL
393382

394383
static void do_profile_hits(int type, void *__pc, unsigned int nr_hits)
395384
{
@@ -531,83 +520,43 @@ static const struct file_operations proc_profile_operations = {
531520
.llseek = default_llseek,
532521
};
533522

534-
#ifdef CONFIG_SMP
535-
static void profile_nop(void *unused)
536-
{
537-
}
538-
539-
static int create_hash_tables(void)
523+
int __ref create_proc_profile(void)
540524
{
541-
int cpu;
542-
543-
for_each_online_cpu(cpu) {
544-
int node = cpu_to_mem(cpu);
545-
struct page *page;
546-
547-
page = __alloc_pages_node(node,
548-
GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE,
549-
0);
550-
if (!page)
551-
goto out_cleanup;
552-
per_cpu(cpu_profile_hits, cpu)[1]
553-
= (struct profile_hit *)page_address(page);
554-
page = __alloc_pages_node(node,
555-
GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE,
556-
0);
557-
if (!page)
558-
goto out_cleanup;
559-
per_cpu(cpu_profile_hits, cpu)[0]
560-
= (struct profile_hit *)page_address(page);
561-
}
562-
return 0;
563-
out_cleanup:
564-
prof_on = 0;
565-
smp_mb();
566-
on_each_cpu(profile_nop, NULL, 1);
567-
for_each_online_cpu(cpu) {
568-
struct page *page;
569-
570-
if (per_cpu(cpu_profile_hits, cpu)[0]) {
571-
page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
572-
per_cpu(cpu_profile_hits, cpu)[0] = NULL;
573-
__free_page(page);
574-
}
575-
if (per_cpu(cpu_profile_hits, cpu)[1]) {
576-
page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
577-
per_cpu(cpu_profile_hits, cpu)[1] = NULL;
578-
__free_page(page);
579-
}
580-
}
581-
return -1;
582-
}
583-
#else
584-
#define create_hash_tables() ({ 0; })
525+
struct proc_dir_entry *entry;
526+
#ifdef CONFIG_SMP
527+
enum cpuhp_state online_state;
585528
#endif
586529

587-
int __ref create_proc_profile(void) /* false positive from hotcpu_notifier */
588-
{
589-
struct proc_dir_entry *entry;
590530
int err = 0;
591531

592532
if (!prof_on)
593533
return 0;
594-
595-
cpu_notifier_register_begin();
596-
597-
if (create_hash_tables()) {
598-
err = -ENOMEM;
599-
goto out;
600-
}
601-
534+
#ifdef CONFIG_SMP
535+
err = cpuhp_setup_state(CPUHP_PROFILE_PREPARE, "PROFILE_PREPARE",
536+
profile_prepare_cpu, profile_dead_cpu);
537+
if (err)
538+
return err;
539+
540+
err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "AP_PROFILE_ONLINE",
541+
profile_online_cpu, NULL);
542+
if (err < 0)
543+
goto err_state_prep;
544+
online_state = err;
545+
err = 0;
546+
#endif
602547
entry = proc_create("profile", S_IWUSR | S_IRUGO,
603548
NULL, &proc_profile_operations);
604549
if (!entry)
605-
goto out;
550+
goto err_state_onl;
606551
proc_set_size(entry, (1 + prof_len) * sizeof(atomic_t));
607-
__hotcpu_notifier(profile_cpu_callback, 0);
608552

609-
out:
610-
cpu_notifier_register_done();
553+
return err;
554+
err_state_onl:
555+
#ifdef CONFIG_SMP
556+
cpuhp_remove_state(online_state);
557+
err_state_prep:
558+
cpuhp_remove_state(CPUHP_PROFILE_PREPARE);
559+
#endif
611560
return err;
612561
}
613562
subsys_initcall(create_proc_profile);

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