lkml.org 
[lkml]   [2016]   [Jul]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:smp/hotplug] profile: Convert to hotplug state machine
Commit-ID:  e722d8daafb974b9ad1bbaf42f384a5ea5929f5f
Gitweb: http://git.kernel.org/tip/e722d8daafb974b9ad1bbaf42f384a5ea5929f5f
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate: Wed, 13 Jul 2016 17:16:59 +0000
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 15 Jul 2016 10:41:42 +0200

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>
---
include/linux/cpuhotplug.h | 1 +
kernel/profile.c | 181 ++++++++++++++++-----------------------------
2 files changed, 66 insertions(+), 116 deletions(-)

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 15d46d2..ace5ad0 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -16,6 +16,7 @@ enum cpuhp_state {
CPUHP_X86_APB_DEAD,
CPUHP_WORKQUEUE_PREP,
CPUHP_HRTIMERS_PREPARE,
+ CPUHP_PROFILE_PREPARE,
CPUHP_TIMERS_DEAD,
CPUHP_NOTIFY_PREPARE,
CPUHP_BRINGUP_CPU,
diff --git a/kernel/profile.c b/kernel/profile.c
index c2199e9..2dbccf2 100644
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -328,68 +328,57 @@ out:
put_cpu();
}

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

- switch (action) {
- case CPU_UP_PREPARE:
- case CPU_UP_PREPARE_FROZEN:
- node = cpu_to_mem(cpu);
- per_cpu(cpu_profile_flip, cpu) = 0;
- if (!per_cpu(cpu_profile_hits, cpu)[1]) {
- page = __alloc_pages_node(node,
- GFP_KERNEL | __GFP_ZERO,
- 0);
- if (!page)
- return notifier_from_errno(-ENOMEM);
- per_cpu(cpu_profile_hits, cpu)[1] = page_address(page);
- }
- if (!per_cpu(cpu_profile_hits, cpu)[0]) {
- page = __alloc_pages_node(node,
- GFP_KERNEL | __GFP_ZERO,
- 0);
- if (!page)
- goto out_free;
- per_cpu(cpu_profile_hits, cpu)[0] = page_address(page);
- }
- break;
-out_free:
- page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
- per_cpu(cpu_profile_hits, cpu)[1] = NULL;
- __free_page(page);
- return notifier_from_errno(-ENOMEM);
- case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- if (prof_cpu_mask != NULL)
- cpumask_set_cpu(cpu, prof_cpu_mask);
- break;
- case CPU_UP_CANCELED:
- case CPU_UP_CANCELED_FROZEN:
- case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- if (prof_cpu_mask != NULL)
- cpumask_clear_cpu(cpu, prof_cpu_mask);
- if (per_cpu(cpu_profile_hits, cpu)[0]) {
- page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
- per_cpu(cpu_profile_hits, cpu)[0] = NULL;
+ if (prof_cpu_mask != NULL)
+ cpumask_clear_cpu(cpu, prof_cpu_mask);
+
+ for (i = 0; i < 2; i++) {
+ if (per_cpu(cpu_profile_hits, cpu)[i]) {
+ page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[i]);
+ per_cpu(cpu_profile_hits, cpu)[i] = NULL;
__free_page(page);
}
- if (per_cpu(cpu_profile_hits, cpu)[1]) {
- page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
- per_cpu(cpu_profile_hits, cpu)[1] = NULL;
- __free_page(page);
+ }
+ return 0;
+}
+
+static int profile_prepare_cpu(unsigned int cpu)
+{
+ int i, node = cpu_to_mem(cpu);
+ struct page *page;
+
+ per_cpu(cpu_profile_flip, cpu) = 0;
+
+ for (i = 0; i < 2; i++) {
+ if (per_cpu(cpu_profile_hits, cpu)[i])
+ continue;
+
+ page = __alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
+ if (!page) {
+ profile_dead_cpu(cpu);
+ return -ENOMEM;
}
- break;
+ per_cpu(cpu_profile_hits, cpu)[i] = page_address(page);
+
}
- return NOTIFY_OK;
+ return 0;
+}
+
+static int profile_online_cpu(unsigned int cpu)
+{
+ if (prof_cpu_mask != NULL)
+ cpumask_set_cpu(cpu, prof_cpu_mask);
+
+ return 0;
}
+
#else /* !CONFIG_SMP */
#define profile_flip_buffers() do { } while (0)
#define profile_discard_flip_buffers() do { } while (0)
-#define profile_cpu_callback NULL

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

-#ifdef CONFIG_SMP
-static void profile_nop(void *unused)
-{
-}
-
-static int create_hash_tables(void)
+int __ref create_proc_profile(void)
{
- int cpu;
-
- for_each_online_cpu(cpu) {
- int node = cpu_to_mem(cpu);
- struct page *page;
-
- page = __alloc_pages_node(node,
- GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE,
- 0);
- if (!page)
- goto out_cleanup;
- per_cpu(cpu_profile_hits, cpu)[1]
- = (struct profile_hit *)page_address(page);
- page = __alloc_pages_node(node,
- GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE,
- 0);
- if (!page)
- goto out_cleanup;
- per_cpu(cpu_profile_hits, cpu)[0]
- = (struct profile_hit *)page_address(page);
- }
- return 0;
-out_cleanup:
- prof_on = 0;
- smp_mb();
- on_each_cpu(profile_nop, NULL, 1);
- for_each_online_cpu(cpu) {
- struct page *page;
-
- if (per_cpu(cpu_profile_hits, cpu)[0]) {
- page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);
- per_cpu(cpu_profile_hits, cpu)[0] = NULL;
- __free_page(page);
- }
- if (per_cpu(cpu_profile_hits, cpu)[1]) {
- page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);
- per_cpu(cpu_profile_hits, cpu)[1] = NULL;
- __free_page(page);
- }
- }
- return -1;
-}
-#else
-#define create_hash_tables() ({ 0; })
+ struct proc_dir_entry *entry;
+#ifdef CONFIG_SMP
+ enum cpuhp_state online_state;
#endif

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

if (!prof_on)
return 0;
-
- cpu_notifier_register_begin();
-
- if (create_hash_tables()) {
- err = -ENOMEM;
- goto out;
- }
-
+#ifdef CONFIG_SMP
+ err = cpuhp_setup_state(CPUHP_PROFILE_PREPARE, "PROFILE_PREPARE",
+ profile_prepare_cpu, profile_dead_cpu);
+ if (err)
+ return err;
+
+ err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "AP_PROFILE_ONLINE",
+ profile_online_cpu, NULL);
+ if (err < 0)
+ goto err_state_prep;
+ online_state = err;
+ err = 0;
+#endif
entry = proc_create("profile", S_IWUSR | S_IRUGO,
NULL, &proc_profile_operations);
if (!entry)
- goto out;
+ goto err_state_onl;
proc_set_size(entry, (1 + prof_len) * sizeof(atomic_t));
- __hotcpu_notifier(profile_cpu_callback, 0);

-out:
- cpu_notifier_register_done();
+ return err;
+err_state_onl:
+#ifdef CONFIG_SMP
+ cpuhp_remove_state(online_state);
+err_state_prep:
+ cpuhp_remove_state(CPUHP_PROFILE_PREPARE);
+#endif
return err;
}
subsys_initcall(create_proc_profile);
\
 
 \ /
  Last update: 2016-07-19 10:21    [W:0.384 / U:9.072 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site