From: Daniel Bristot de Oliveira <bristot@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: Steven Rostedt <rostedt@goodmis.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Ingo Molnar <mingo@redhat.com>, Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"Joel Fernandes (Google)" <joel@joelfernandes.org>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Tommaso Cucinotta <tommaso.cucinotta@santannapisa.it>,
Romulo Silva de Oliveira <romulo.deoliveira@ufsc.br>,
Clark Williams <williams@redhat.com>,
x86@kernel.org
Subject: [RFC PATCH 3/7] trace: Optimize trace_get_context_bit()
Date: Tue, 2 Apr 2019 22:03:55 +0200 [thread overview]
Message-ID: <d4efd910035c5b5eaa9f54eea64f8fef2c33339d.1554234787.git.bristot@redhat.com> (raw)
In-Reply-To: <cover.1554234787.git.bristot@redhat.com>
trace_get_context_bit() and trace_recursive_lock() uses the same logic,
but the second reads the per_cpu variable only once.
Uses the trace_recursive_lock()'s logic in trace_get_context_bit().
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Tommaso Cucinotta <tommaso.cucinotta@santannapisa.it>
Cc: Romulo Silva de Oliveira <romulo.deoliveira@ufsc.br>
Cc: Clark Williams <williams@redhat.com>
Cc: linux-kernel@vger.kernel.org
Cc: x86@kernel.org
---
kernel/trace/trace.h | 19 ++++++-------------
1 file changed, 6 insertions(+), 13 deletions(-)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index dad2f0cd7208..09318748fab8 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -635,20 +635,13 @@ enum {
static __always_inline int trace_get_context_bit(void)
{
- int bit;
-
- if (in_interrupt()) {
- if (in_nmi())
- bit = TRACE_CTX_NMI;
+ unsigned long pc = preempt_count();
- else if (in_irq())
- bit = TRACE_CTX_IRQ;
- else
- bit = TRACE_CTX_SOFTIRQ;
- } else
- bit = TRACE_CTX_NORMAL;
-
- return bit;
+ if (pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET))
+ return pc & NMI_MASK ? TRACE_CTX_NMI :
+ pc & HARDIRQ_MASK ? TRACE_CTX_IRQ : TRACE_CTX_SOFTIRQ;
+ else
+ return TRACE_CTX_NORMAL;
}
static __always_inline int trace_test_and_set_recursion(int start, int max)
--
2.20.1
next prev parent reply other threads:[~2019-04-02 20:04 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-02 20:03 [RFC PATCH 0/7] Early task context tracking Daniel Bristot de Oliveira
2019-04-02 20:03 ` [RFC PATCH 1/7] x86/entry: Add support for early " Daniel Bristot de Oliveira
2019-04-02 20:03 ` [RFC PATCH 2/7] trace: Move the trace recursion context enum to trace.h and reuse it Daniel Bristot de Oliveira
2019-04-02 20:03 ` Daniel Bristot de Oliveira [this message]
2019-04-02 20:03 ` [RFC PATCH 4/7] trace/ring_buffer: Use trace_get_context_bit() Daniel Bristot de Oliveira
2019-04-02 20:03 ` [RFC PATCH 5/7] trace: Use early task context tracking if available Daniel Bristot de Oliveira
2019-04-02 20:03 ` [RFC PATCH 6/7] events: Create an trace_get_context_bit() Daniel Bristot de Oliveira
2019-04-02 20:03 ` [RFC PATCH 7/7] events: Use early task context tracking if available Daniel Bristot de Oliveira
2019-04-04 0:01 ` [RFC PATCH 0/7] Early task context tracking Andy Lutomirski
2019-04-04 9:42 ` Peter Zijlstra
2019-04-08 12:47 ` Daniel Bristot de Oliveira
2019-04-08 16:08 ` Andy Lutomirski
2019-04-04 17:40 ` Joel Fernandes
2019-04-08 12:54 ` Daniel Bristot de Oliveira
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