perf: Kill the dead !vma->vm_mm code in perf_event_mmap_event() (32c5fb7e) · Commits · 戴 / test

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:

Oleg Nesterov <oleg@redhat.com> Signed-off-by:

Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131016200945.GB23214@redhat.com Signed-off-by:

Ingo Molnar <mingo@kernel.org>

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;

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