perf_counter: provide an mlock threshold

Provide a threshold to relax the mlock accounting, increasing usability.

Each counter gets perf_counter_mlock_kb for free.

[ Impact: allow more mmap buffering ]

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090505155437.112113632@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 8 insertions, 0 deletions

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