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-rw-r--r--kernel/cpu.c19
1 files changed, 13 insertions, 6 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 90a3d017b90c..5d220234b3ca 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -86,6 +86,16 @@ static struct {
86#define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map) 86#define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map)
87#define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map) 87#define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map)
88 88
89static void apply_puts_pending(int max)
90{
91 int delta;
92
93 if (atomic_read(&cpu_hotplug.puts_pending) >= max) {
94 delta = atomic_xchg(&cpu_hotplug.puts_pending, 0);
95 cpu_hotplug.refcount -= delta;
96 }
97}
98
89void get_online_cpus(void) 99void get_online_cpus(void)
90{ 100{
91 might_sleep(); 101 might_sleep();
@@ -93,6 +103,7 @@ void get_online_cpus(void)
93 return; 103 return;
94 cpuhp_lock_acquire_read(); 104 cpuhp_lock_acquire_read();
95 mutex_lock(&cpu_hotplug.lock); 105 mutex_lock(&cpu_hotplug.lock);
106 apply_puts_pending(65536);
96 cpu_hotplug.refcount++; 107 cpu_hotplug.refcount++;
97 mutex_unlock(&cpu_hotplug.lock); 108 mutex_unlock(&cpu_hotplug.lock);
98} 109}
@@ -105,6 +116,7 @@ bool try_get_online_cpus(void)
105 if (!mutex_trylock(&cpu_hotplug.lock)) 116 if (!mutex_trylock(&cpu_hotplug.lock))
106 return false; 117 return false;
107 cpuhp_lock_acquire_tryread(); 118 cpuhp_lock_acquire_tryread();
119 apply_puts_pending(65536);
108 cpu_hotplug.refcount++; 120 cpu_hotplug.refcount++;
109 mutex_unlock(&cpu_hotplug.lock); 121 mutex_unlock(&cpu_hotplug.lock);
110 return true; 122 return true;
@@ -161,12 +173,7 @@ void cpu_hotplug_begin(void)
161 cpuhp_lock_acquire(); 173 cpuhp_lock_acquire();
162 for (;;) { 174 for (;;) {
163 mutex_lock(&cpu_hotplug.lock); 175 mutex_lock(&cpu_hotplug.lock);
164 if (atomic_read(&cpu_hotplug.puts_pending)) { 176 apply_puts_pending(1);
165 int delta;
166
167 delta = atomic_xchg(&cpu_hotplug.puts_pending, 0);
168 cpu_hotplug.refcount -= delta;
169 }
170 if (likely(!cpu_hotplug.refcount)) 177 if (likely(!cpu_hotplug.refcount))
171 break; 178 break;
172 __set_current_state(TASK_UNINTERRUPTIBLE); 179 __set_current_state(TASK_UNINTERRUPTIBLE);