Re: [PATCH] perf/core: don't WARN for impossible rb sizes

On 2/12/2019 9:07 PM, Peter Zijlstra wrote: On Tue, Feb 12, 2019 at 10:42:38AM +0800, Jin, Yao wrote: diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index 4a9937076331..309ef5a64af5 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -734,6

Re: [PATCH] perf/core: don't WARN for impossible rb sizes

On Tue, Feb 12, 2019 at 10:42:38AM +0800, Jin, Yao wrote: > > diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c > > index 4a9937076331..309ef5a64af5 100644 > > --- a/kernel/events/ring_buffer.c > > +++ b/kernel/events/ring_buffer.c > > @@ -734,6 +734,9 @@ struct ring_buffer

Re: [PATCH] perf/core: don't WARN for impossible rb sizes

Hi Mark, Looks I hit a regression issue on SKL desktop. For example, root@skl:/tmp# perf record -g -a failed to mmap with 12 (Cannot allocate memory) In this case, size = 1264, order_base_2 = 11, MAX_ORDER = 11 if (order_base_2(size) >= MAX_ORDER) goto fail; It will goto fail

Re: [PATCH] perf/core: don't WARN for impossible rb sizes

Hi Mark, On 10/01/2019 14:27, Mark Rutland wrote: > The perf tool uses /proc/sys/kernel/perf_event_mlock_kb to determine how > large its ringbuffer mmap should be. This can be configured to arbitrary > values, which can be larger than the maximum possible allocation from > kmalloc. > > When this

[PATCH] perf/core: don't WARN for impossible rb sizes

The perf tool uses /proc/sys/kernel/perf_event_mlock_kb to determine how large its ringbuffer mmap should be. This can be configured to arbitrary values, which can be larger than the maximum possible allocation from kmalloc. When this is configured to a suitably large value (e.g. thanks to the