[tip:perf/urgent] perf: Rebase max unprivileged mlock threshold on top of page size

[tip-bot for Frederic Weisbecker <fweisbec@gmail.com>]

Commit-ID:  20443384fe090c5f8aeb016e7e85659c5bbdd69f
Gitweb:     http://git.kernel.org/tip/20443384fe090c5f8aeb016e7e85659c5bbdd69f
Author:     Frederic Weisbecker <fweisbec@gmail.com>
AuthorDate: Thu, 31 Mar 2011 03:33:29 +0200
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 31 Mar 2011 13:02:54 +0200

perf: Rebase max unprivileged mlock threshold on top of page size

Ensure we allow 512 kiB + 1 page for user control without
assuming a 4096 bytes page size.

Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: <stable@kernel.org>
LKML-Reference: <1301535209-9679-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/perf_event.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index c75925c..2616909 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -145,8 +145,8 @@ static struct srcu_struct pmus_srcu;
  */
 int sysctl_perf_event_paranoid __read_mostly = 1;
 
-/* Minimum for 128 pages + 1 for the user control page */
-int sysctl_perf_event_mlock __read_mostly = 516; /* 'free' kb per user */
+/* Minimum for 512 kiB + 1 user control page */
+int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
 
 /*
  * max perf event sample rate