Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

[mirror_ubuntu-artful-kernel.git] / kernel / events / callchain.c

diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index 343c22f5e867de2bbe6c2220535b413a6ea0f4ed..b9325e7dcba1088d74e2502177d2a22ececce4dc 100644 (file)
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -18,6 +18,14 @@ struct callchain_cpus_entries {
        struct perf_callchain_entry     *cpu_entries[0];
 };
 
+int sysctl_perf_event_max_stack __read_mostly = PERF_MAX_STACK_DEPTH;
+
+static inline size_t perf_callchain_entry__sizeof(void)
+{
+       return (sizeof(struct perf_callchain_entry) +
+               sizeof(__u64) * sysctl_perf_event_max_stack);
+}
+
 static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]);
 static atomic_t nr_callchain_events;
 static DEFINE_MUTEX(callchain_mutex);
@@ -73,7 +81,7 @@ static int alloc_callchain_buffers(void)
        if (!entries)
                return -ENOMEM;
 
-       size = sizeof(struct perf_callchain_entry) * PERF_NR_CONTEXTS;
+       size = perf_callchain_entry__sizeof() * PERF_NR_CONTEXTS;
 
        for_each_possible_cpu(cpu) {
                entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL,
@@ -147,7 +155,8 @@ static struct perf_callchain_entry *get_callchain_entry(int *rctx)
 
        cpu = smp_processor_id();
 
-       return &entries->cpu_entries[cpu][*rctx];
+       return (((void *)entries->cpu_entries[cpu]) +
+               (*rctx * perf_callchain_entry__sizeof()));
 }
 
 static void
@@ -215,3 +224,25 @@ exit_put:
 
        return entry;
 }
+
+int perf_event_max_stack_handler(struct ctl_table *table, int write,
+                                void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+       int new_value = sysctl_perf_event_max_stack, ret;
+       struct ctl_table new_table = *table;
+
+       new_table.data = &new_value;
+       ret = proc_dointvec_minmax(&new_table, write, buffer, lenp, ppos);
+       if (ret || !write)
+               return ret;
+
+       mutex_lock(&callchain_mutex);
+       if (atomic_read(&nr_callchain_events))
+               ret = -EBUSY;
+       else
+               sysctl_perf_event_max_stack = new_value;
+
+       mutex_unlock(&callchain_mutex);
+
+       return ret;
+}