[PATCH 10/22] mm/zsmalloc: Convert to hotplug state machine

From: Sebastian Andrzej Siewior
Date: Sat Nov 26 2016 - 18:17:50 EST


Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx>
CC: linux-mm@xxxxxxxxx
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
include/linux/cpuhotplug.h | 1 +
mm/zsmalloc.c | 67 +++++++++-------------------------------------
2 files changed, 14 insertions(+), 54 deletions(-)

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 4ebd1bc27f8d..9f29dd996088 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -64,6 +64,7 @@ enum cpuhp_state {
CPUHP_NET_IUCV_PREPARE,
CPUHP_ARM_BL_PREPARE,
CPUHP_TRACE_RB_PREPARE,
+ CPUHP_MM_ZS_PREPARE,
CPUHP_TIMERS_DEAD,
CPUHP_NOTF_ERR_INJ_PREPARE,
CPUHP_MIPS_SOC_PREPARE,
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index b0bc023d25c5..9cc3c0b2c2c1 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -1284,61 +1284,21 @@ static void __zs_unmap_object(struct mapping_area *area,

#endif /* CONFIG_PGTABLE_MAPPING */

-static int zs_cpu_notifier(struct notifier_block *nb, unsigned long action,
- void *pcpu)
+static int zs_cpu_prepare(unsigned int cpu)
{
- int ret, cpu = (long)pcpu;
struct mapping_area *area;

- switch (action) {
- case CPU_UP_PREPARE:
- area = &per_cpu(zs_map_area, cpu);
- ret = __zs_cpu_up(area);
- if (ret)
- return notifier_from_errno(ret);
- break;
- case CPU_DEAD:
- case CPU_UP_CANCELED:
- area = &per_cpu(zs_map_area, cpu);
- __zs_cpu_down(area);
- break;
- }
-
- return NOTIFY_OK;
+ area = &per_cpu(zs_map_area, cpu);
+ return __zs_cpu_up(area);
}

-static struct notifier_block zs_cpu_nb = {
- .notifier_call = zs_cpu_notifier
-};
-
-static int zs_register_cpu_notifier(void)
+static int zs_cpu_dead(unsigned int cpu)
{
- int cpu, uninitialized_var(ret);
+ struct mapping_area *area;

- cpu_notifier_register_begin();
-
- __register_cpu_notifier(&zs_cpu_nb);
- for_each_online_cpu(cpu) {
- ret = zs_cpu_notifier(NULL, CPU_UP_PREPARE, (void *)(long)cpu);
- if (notifier_to_errno(ret))
- break;
- }
-
- cpu_notifier_register_done();
- return notifier_to_errno(ret);
-}
-
-static void zs_unregister_cpu_notifier(void)
-{
- int cpu;
-
- cpu_notifier_register_begin();
-
- for_each_online_cpu(cpu)
- zs_cpu_notifier(NULL, CPU_DEAD, (void *)(long)cpu);
- __unregister_cpu_notifier(&zs_cpu_nb);
-
- cpu_notifier_register_done();
+ area = &per_cpu(zs_map_area, cpu);
+ __zs_cpu_down(area);
+ return 0;
}

static void __init init_zs_size_classes(void)
@@ -2534,10 +2494,10 @@ static int __init zs_init(void)
if (ret)
goto out;

- ret = zs_register_cpu_notifier();
-
+ ret = cpuhp_setup_state(CPUHP_MM_ZS_PREPARE, "mm/zsmalloc:prepare",
+ zs_cpu_prepare, zs_cpu_dead);
if (ret)
- goto notifier_fail;
+ goto hp_setup_fail;

init_zs_size_classes();

@@ -2549,8 +2509,7 @@ static int __init zs_init(void)

return 0;

-notifier_fail:
- zs_unregister_cpu_notifier();
+hp_setup_fail:
zsmalloc_unmount();
out:
return ret;
@@ -2562,7 +2521,7 @@ static void __exit zs_exit(void)
zpool_unregister_driver(&zs_zpool_driver);
#endif
zsmalloc_unmount();
- zs_unregister_cpu_notifier();
+ cpuhp_remove_state(CPUHP_MM_ZS_PREPARE);

zs_stat_exit();
}
--
2.10.2