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Commit 32c5fb7e authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Ingo Molnar
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perf: Kill the dead !vma->vm_mm code in perf_event_mmap_event() 



1. perf_event_mmap(vma) is never called with a gate_vma-like arg,
   remove the "if (!vma->vm_mm)" code.

2. arch_vma_name() can use the chached value of mmap_event->vma.

3. Change the code to not call arch_vma_name() twice.

4. Purely cosmetic, but since we use "goto got_name" all the time
   remove "else" from "[stack]" branch just for symmetry.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20131016200945.GB23214@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent d9494cb4

kernel/events/core.c

+6 −8
Original line number Diff line number Diff line
@@ -5136,21 +5136,19 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) 
		min = MINOR(dev);



	} else {

		if (arch_vma_name(mmap_event->vma)) {

			name = strncpy(tmp, arch_vma_name(mmap_event->vma),

				       sizeof(tmp) - 1);

		name = arch_vma_name(vma);

		if (name) {

			name = strncpy(tmp, name, sizeof(tmp) - 1);

			tmp[sizeof(tmp) - 1] = '\0';

			goto got_name;

		}



		if (!vma->vm_mm) {

			name = strncpy(tmp, "[vdso]", sizeof(tmp));

			goto got_name;

		} else if (vma->vm_start <= vma->vm_mm->start_brk &&

		if (vma->vm_start <= vma->vm_mm->start_brk &&

				vma->vm_end >= vma->vm_mm->brk) {

			name = strncpy(tmp, "[heap]", sizeof(tmp));

			goto got_name;

		} else if (vma->vm_start <= vma->vm_mm->start_stack &&

		}

		if (vma->vm_start <= vma->vm_mm->start_stack &&

				vma->vm_end >= vma->vm_mm->start_stack) {

			name = strncpy(tmp, "[stack]", sizeof(tmp));

			goto got_name;