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| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2021-10-15 13:42:40 -0400 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2021-10-19 20:33:20 -0400 |
| commit | 9b84fadc444de5456ab5f5487e2108311c724c3f (patch) | |
| tree | 0bbafa429f2728795926fbe1b152ea2415a339f0 /kernel/trace/ring_buffer.c | |
| parent | 7ce1bb83a14019f8c396d57ec704d19478747716 (diff) | |
| download | linux-9b84fadc444de5456ab5f5487e2108311c724c3f.tar.gz | |
tracing: Reuse logic from perf's get_recursion_context()
Instead of having branches that adds noise to the branch prediction, use the addition logic to set the bit for the level of interrupt context that the state is currently in. This copies the logic from perf's get_recursion_context() function. Link: https://lore.kernel.org/all/20211015161702.GF174703@worktop.programming.kicks-ass.net/ Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/ring_buffer.c')
| -rw-r--r-- | kernel/trace/ring_buffer.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index c5a3fbf19617..15d4380006e3 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -3168,13 +3168,13 @@ trace_recursive_lock(struct ring_buffer_per_cpu *cpu_buffer) { unsigned int val = cpu_buffer->current_context; unsigned long pc = preempt_count(); - int bit; + int bit = 0; - if (!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET))) - bit = RB_CTX_NORMAL; - else - bit = pc & NMI_MASK ? RB_CTX_NMI : - pc & HARDIRQ_MASK ? RB_CTX_IRQ : RB_CTX_SOFTIRQ; + bit += !!(pc & (NMI_MASK)); + bit += !!(pc & (NMI_MASK | HARDIRQ_MASK)); + bit += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET)); + + bit = RB_CTX_NORMAL - bit; if (unlikely(val & (1 << (bit + cpu_buffer->nest)))) { /* |