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perf: Disable PERF_RECORD_MMAP2 support

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For now, we disable the extended MMAP record support (MMAP2).

We have identified cases where it would not report the correct mapping
information, clone(VM_CLONE) but with separate pids.  We will revisit
the support once we find a solution for this case.

The patch changes the kernel to return EINVAL if attr->mmap2 is set. The
patch also modifies the perf tool to use regular PERF_RECORD_MMAP for
synthetic events and it also prevents the tool from requesting
attr->mmap2 mode because the kernel would reject it.

The support will be revisited once the kenrel interface is updated.

In V2, we reduce the patch to the strict minimum.

In V3, we avoid calling perf_event_open() with mmap2 set because we know
it will fail and require fallback retry.

Signed-off-by: Stephane Eranian <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/20131017173215.GA8820@quad
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
This commit is contained in:
Stephane Eranian 2013-10-17 19:32:15 +02:00 • committed by Arnaldo Carvalho de Melo
commit 3090ffb5a2
3 changed files with 17 additions and 18 deletions
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4
kernel/events/core.c
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@ -6767,6 +6767,10 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr,
if (ret)
return -EFAULT;
/* disabled for now */
if (attr->mmap2)
return -EINVAL;
if (attr->__reserved_1)
return -EINVAL;