Commit a3862d3f authored May 24, 2009 by Ingo Molnar

perf_counter: Increase mmap limit

In a default 'perf top' run the tool will create a counter for
each online CPU. With enough CPUs this will eventually exhaust
the default limit.

So scale it up with the number of online CPUs.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent c2990a2a

kernel/perf_counter.c

+6 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1704,6 +1704,12 @@ static int perf_mmap(struct file file, struct vm_area_struct vma)

	user_extra = nr_pages + 1;		user_extra = nr_pages + 1;
	user_lock_limit = sysctl_perf_counter_mlock >> (PAGE_SHIFT - 10);		user_lock_limit = sysctl_perf_counter_mlock >> (PAGE_SHIFT - 10);

			/*
			* Increase the limit linearly with more CPUs:
			*/
			user_lock_limit *= num_online_cpus();

	user_locked = atomic_long_read(&user->locked_vm) + user_extra;		user_locked = atomic_long_read(&user->locked_vm) + user_extra;

	extra = 0;		extra = 0;