[tip:smp/hotplug] mm/zswap: Convert dst-mem to hotplug state machine

[tip-bot for Sebastian Andrzej Siewior]

Commit-ID:  ad7ed7708db9ff388450935645816d44bf08a56d
Gitweb: http://git.kernel.org/tip/ad7ed7708db9ff388450935645816d44bf08a56d
Author: Sebastian Andrzej Siewior 
AuthorDate: Sun, 27 Nov 2016 00:13:39 +0100
Committer:  Thomas Gleixner 
CommitDate: Fri, 2 Dec 2016 00:52:36 +0100

mm/zswap: Convert dst-mem to hotplug state machine

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

Signed-off-by: Sebastian Andrzej Siewior 
Cc: linux...@kvack.org
Cc: Seth Jennings 
Cc: r...@linutronix.de
Link: http://lkml.kernel.org/r/20161126231350.10321-12-bige...@linutronix.de
Signed-off-by: Thomas Gleixner 

---
 include/linux/cpuhotplug.h |  1 +
 mm/zswap.c | 73 +++---
 2 files changed, 18 insertions(+), 56 deletions(-)

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 9f29dd9..62f51a4 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -65,6 +65,7 @@ enum cpuhp_state {
CPUHP_ARM_BL_PREPARE,
CPUHP_TRACE_RB_PREPARE,
CPUHP_MM_ZS_PREPARE,
+   CPUHP_MM_ZSWP_MEM_PREPARE,
CPUHP_TIMERS_DEAD,
CPUHP_NOTF_ERR_INJ_PREPARE,
CPUHP_MIPS_SOC_PREPARE,
diff --git a/mm/zswap.c b/mm/zswap.c
index 275b22c..b13aa57 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -352,70 +352,28 @@ static struct zswap_entry *zswap_entry_find_get(struct 
rb_root *root,
 **/
 static DEFINE_PER_CPU(u8 *, zswap_dstmem);
 
-static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
+static int zswap_dstmem_prepare(unsigned int cpu)
 {
u8 *dst;
 
-   switch (action) {
-   case CPU_UP_PREPARE:
-   dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
-   if (!dst) {
-   pr_err("can't allocate compressor buffer\n");
-   return NOTIFY_BAD;
-   }
-   per_cpu(zswap_dstmem, cpu) = dst;
-   break;
-   case CPU_DEAD:
-   case CPU_UP_CANCELED:
-   dst = per_cpu(zswap_dstmem, cpu);
-   kfree(dst);
-   per_cpu(zswap_dstmem, cpu) = NULL;
-   break;
-   default:
-   break;
+   dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
+   if (!dst) {
+   pr_err("can't allocate compressor buffer\n");
+   return -ENOMEM;
}
-   return NOTIFY_OK;
+   per_cpu(zswap_dstmem, cpu) = dst;
+   return 0;
 }
 
-static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
-unsigned long action, void *pcpu)
+static int zswap_dstmem_dead(unsigned int cpu)
 {
-   return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
-}
-
-static struct notifier_block zswap_dstmem_notifier = {
-   .notifier_call =zswap_cpu_dstmem_notifier,
-};
+   u8 *dst;
 
-static int __init zswap_cpu_dstmem_init(void)
-{
-   unsigned long cpu;
+   dst = per_cpu(zswap_dstmem, cpu);
+   kfree(dst);
+   per_cpu(zswap_dstmem, cpu) = NULL;
 
-   cpu_notifier_register_begin();
-   for_each_online_cpu(cpu)
-   if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
-   NOTIFY_BAD)
-   goto cleanup;
-   __register_cpu_notifier(_dstmem_notifier);
-   cpu_notifier_register_done();
return 0;
-
-cleanup:
-   for_each_online_cpu(cpu)
-   __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
-   cpu_notifier_register_done();
-   return -ENOMEM;
-}
-
-static void zswap_cpu_dstmem_destroy(void)
-{
-   unsigned long cpu;
-
-   cpu_notifier_register_begin();
-   for_each_online_cpu(cpu)
-   __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
-   __unregister_cpu_notifier(_dstmem_notifier);
-   cpu_notifier_register_done();
 }
 
 static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
@@ -1238,6 +1196,7 @@ static void __exit zswap_debugfs_exit(void) { }
 static int __init init_zswap(void)
 {
struct zswap_pool *pool;
+   int ret;
 
zswap_init_started = true;
 
@@ -1246,7 +1205,9 @@ static int __init init_zswap(void)
goto cache_fail;
}
 
-   if (zswap_cpu_dstmem_init()) {
+   ret = cpuhp_setup_state(CPUHP_MM_ZSWP_MEM_PREPARE, "mm/zswap:prepare",
+   zswap_dstmem_prepare, zswap_dstmem_dead);
+   if (ret) {
pr_err("dstmem alloc failed\n");
goto dstmem_fail;
}
@@ -1267,7 +1228,7 @@ static int __init init_zswap(void)
return 0;
 
 pool_fail:
-   zswap_cpu_dstmem_destroy();
+   cpuhp_remove_state(CPUHP_MM_ZSWP_MEM_PREPARE);
 dstmem_fail:
zswap_entry_cache_destroy();
 

[tip:smp/hotplug] mm/zswap: Convert dst-mem to hotplug state machine

[tip-bot for Sebastian Andrzej Siewior]

Commit-ID:  ad7ed7708db9ff388450935645816d44bf08a56d
Gitweb: http://git.kernel.org/tip/ad7ed7708db9ff388450935645816d44bf08a56d
Author: Sebastian Andrzej Siewior 
AuthorDate: Sun, 27 Nov 2016 00:13:39 +0100
Committer:  Thomas Gleixner 
CommitDate: Fri, 2 Dec 2016 00:52:36 +0100

mm/zswap: Convert dst-mem to hotplug state machine

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

Signed-off-by: Sebastian Andrzej Siewior 
Cc: linux...@kvack.org
Cc: Seth Jennings 
Cc: r...@linutronix.de
Link: http://lkml.kernel.org/r/20161126231350.10321-12-bige...@linutronix.de
Signed-off-by: Thomas Gleixner 

---
 include/linux/cpuhotplug.h |  1 +
 mm/zswap.c | 73 +++---
 2 files changed, 18 insertions(+), 56 deletions(-)

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 9f29dd9..62f51a4 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -65,6 +65,7 @@ enum cpuhp_state {
CPUHP_ARM_BL_PREPARE,
CPUHP_TRACE_RB_PREPARE,
CPUHP_MM_ZS_PREPARE,
+   CPUHP_MM_ZSWP_MEM_PREPARE,
CPUHP_TIMERS_DEAD,
CPUHP_NOTF_ERR_INJ_PREPARE,
CPUHP_MIPS_SOC_PREPARE,
diff --git a/mm/zswap.c b/mm/zswap.c
index 275b22c..b13aa57 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -352,70 +352,28 @@ static struct zswap_entry *zswap_entry_find_get(struct 
rb_root *root,
 **/
 static DEFINE_PER_CPU(u8 *, zswap_dstmem);
 
-static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
+static int zswap_dstmem_prepare(unsigned int cpu)
 {
u8 *dst;
 
-   switch (action) {
-   case CPU_UP_PREPARE:
-   dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
-   if (!dst) {
-   pr_err("can't allocate compressor buffer\n");
-   return NOTIFY_BAD;
-   }
-   per_cpu(zswap_dstmem, cpu) = dst;
-   break;
-   case CPU_DEAD:
-   case CPU_UP_CANCELED:
-   dst = per_cpu(zswap_dstmem, cpu);
-   kfree(dst);
-   per_cpu(zswap_dstmem, cpu) = NULL;
-   break;
-   default:
-   break;
+   dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
+   if (!dst) {
+   pr_err("can't allocate compressor buffer\n");
+   return -ENOMEM;
}
-   return NOTIFY_OK;
+   per_cpu(zswap_dstmem, cpu) = dst;
+   return 0;
 }
 
-static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
-unsigned long action, void *pcpu)
+static int zswap_dstmem_dead(unsigned int cpu)
 {
-   return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
-}
-
-static struct notifier_block zswap_dstmem_notifier = {
-   .notifier_call =zswap_cpu_dstmem_notifier,
-};
+   u8 *dst;
 
-static int __init zswap_cpu_dstmem_init(void)
-{
-   unsigned long cpu;
+   dst = per_cpu(zswap_dstmem, cpu);
+   kfree(dst);
+   per_cpu(zswap_dstmem, cpu) = NULL;
 
-   cpu_notifier_register_begin();
-   for_each_online_cpu(cpu)
-   if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
-   NOTIFY_BAD)
-   goto cleanup;
-   __register_cpu_notifier(_dstmem_notifier);
-   cpu_notifier_register_done();
return 0;
-
-cleanup:
-   for_each_online_cpu(cpu)
-   __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
-   cpu_notifier_register_done();
-   return -ENOMEM;
-}
-
-static void zswap_cpu_dstmem_destroy(void)
-{
-   unsigned long cpu;
-
-   cpu_notifier_register_begin();
-   for_each_online_cpu(cpu)
-   __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
-   __unregister_cpu_notifier(_dstmem_notifier);
-   cpu_notifier_register_done();
 }
 
 static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
@@ -1238,6 +1196,7 @@ static void __exit zswap_debugfs_exit(void) { }
 static int __init init_zswap(void)
 {
struct zswap_pool *pool;
+   int ret;
 
zswap_init_started = true;
 
@@ -1246,7 +1205,9 @@ static int __init init_zswap(void)
goto cache_fail;
}
 
-   if (zswap_cpu_dstmem_init()) {
+   ret = cpuhp_setup_state(CPUHP_MM_ZSWP_MEM_PREPARE, "mm/zswap:prepare",
+   zswap_dstmem_prepare, zswap_dstmem_dead);
+   if (ret) {
pr_err("dstmem alloc failed\n");
goto dstmem_fail;
}
@@ -1267,7 +1228,7 @@ static int __init init_zswap(void)
return 0;
 
 pool_fail:
-   zswap_cpu_dstmem_destroy();
+   cpuhp_remove_state(CPUHP_MM_ZSWP_MEM_PREPARE);
 dstmem_fail:
zswap_entry_cache_destroy();
 cache_fail: