summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--include/linux/perf_counter.h2
-rw-r--r--kernel/perf_counter.c15
-rw-r--r--kernel/sysctl.c8
3 files changed, 21 insertions, 4 deletions
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 0fcbf34a4f73..00081d84169f 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -358,6 +358,7 @@ struct file;
struct perf_mmap_data {
struct rcu_head rcu_head;
int nr_pages; /* nr of data pages */
+ int nr_locked; /* nr pages mlocked */
atomic_t poll; /* POLL_ for wakeups */
atomic_t head; /* write position */
@@ -575,6 +576,7 @@ struct perf_callchain_entry {
extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);
extern int sysctl_perf_counter_priv;
+extern int sysctl_perf_counter_mlock;
extern void perf_counter_init(void);
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 6e6834e0587e..2d1342738305 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -44,6 +44,7 @@ static atomic_t nr_munmap_tracking __read_mostly;
static atomic_t nr_comm_tracking __read_mostly;
int sysctl_perf_counter_priv __read_mostly; /* do we need to be privileged */
+int sysctl_perf_counter_mlock __read_mostly = 128; /* 'free' kb per counter */
/*
* Lock for (sysadmin-configurable) counter reservations:
@@ -1461,7 +1462,7 @@ static void perf_mmap_close(struct vm_area_struct *vma)
if (atomic_dec_and_mutex_lock(&counter->mmap_count,
&counter->mmap_mutex)) {
- vma->vm_mm->locked_vm -= counter->data->nr_pages + 1;
+ vma->vm_mm->locked_vm -= counter->data->nr_locked;
perf_mmap_data_free(counter);
mutex_unlock(&counter->mmap_mutex);
}
@@ -1480,6 +1481,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
unsigned long nr_pages;
unsigned long locked, lock_limit;
int ret = 0;
+ long extra;
if (!(vma->vm_flags & VM_SHARED) || (vma->vm_flags & VM_WRITE))
return -EINVAL;
@@ -1507,8 +1509,12 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
goto unlock;
}
- locked = vma->vm_mm->locked_vm;
- locked += nr_pages + 1;
+ extra = nr_pages /* + 1 only account the data pages */;
+ extra -= sysctl_perf_counter_mlock >> (PAGE_SHIFT - 10);
+ if (extra < 0)
+ extra = 0;
+
+ locked = vma->vm_mm->locked_vm + extra;
lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
lock_limit >>= PAGE_SHIFT;
@@ -1524,7 +1530,8 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
goto unlock;
atomic_set(&counter->mmap_count, 1);
- vma->vm_mm->locked_vm += nr_pages + 1;
+ vma->vm_mm->locked_vm += extra;
+ counter->data->nr_locked = extra;
unlock:
mutex_unlock(&counter->mmap_mutex);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 8203d70928d5..3b05c2b088d2 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -920,6 +920,14 @@ static struct ctl_table kern_table[] = {
.mode = 0644,
.proc_handler = &proc_dointvec,
},
+ {
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "perf_counter_mlock_kb",
+ .data = &sysctl_perf_counter_mlock,
+ .maxlen = sizeof(sysctl_perf_counter_mlock),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
#endif
/*
* NOTE: do not add new entries to this table unless you have read