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Message-ID: <20241022095241.RFY4Iiu_@linutronix.de> References: <20241021151257.102296-1-bigeasy@linutronix.de> <20241021151257.102296-2-bigeasy@linutronix.de> <20241022031418.12154e63@rorschach.local.home> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20241022031418.12154e63@rorschach.local.home> On 2024-10-22 03:14:18 [-0400], Steven Rostedt wrote: > On Mon, 21 Oct 2024 17:08:40 +0200 > Sebastian Andrzej Siewior wrote: > > > From: Thomas Gleixner > > > > The TRACE_FLAG_IRQS_NOSUPPORT flag is used by tracing_gen_ctx.*() to > > signal that CONFIG_TRACE_IRQFLAGS_SUPPORT is not enabled and tracing IRQ > > flags is not supported. > > > > This could be replaced by using the 0 as flags and then deducting that > > there is no IRQFLAGS_SUPPORT based on the config option. The downside is > > that without CONFIG_TRACE_IRQFLAGS_SUPPORT we can not distinguish > > between no-IRQ passed flags and callers which passed 0. On the upside we > > have room for one additional flags which could be used for LAZY_PREEMPTION. > > > > Remove TRACE_FLAG_IRQS_NOSUPPORT and set it flags are 0 and > > CONFIG_TRACE_IRQFLAGS_SUPPORT is not set. > > We could also add that we have: > > # > # Minimum requirements an architecture has to meet for us to > # be able to offer generic tracing facilities: > # > config TRACING_SUPPORT > bool > depends on TRACE_IRQFLAGS_SUPPORT > depends on STACKTRACE_SUPPORT > default y > > So this can't even be built without TRACE_IRQFLAGS_SUPPORT! Good point. So we could TRACE_FLAG_IRQS_NOSUPPORT since it can't be used. This is since commit 0ea5ee035133a ("tracing: Remove PPC32 wart from config TRACING_SUPPORT"). > > +++ b/include/linux/trace_events.h > > @@ -184,8 +184,7 @@ unsigned int tracing_gen_ctx_irq_test(un > > > > enum trace_flag_type { > > TRACE_FLAG_IRQS_OFF = 0x01, > > - TRACE_FLAG_IRQS_NOSUPPORT = 0x02, > > - TRACE_FLAG_NEED_RESCHED = 0x04, > > + TRACE_FLAG_NEED_RESCHED = 0x02, > > These flags are user visible (I probably should move them into uapi). > They are parsed by libtraceevent. > > Please just remove NOSUPPORT and do not touch NEED_RESCHED. Then I put the lazy bit where we have not NOSUPPORT. > > TRACE_FLAG_HARDIRQ = 0x08, > > TRACE_FLAG_SOFTIRQ = 0x10, > > TRACE_FLAG_PREEMPT_RESCHED = 0x20, > > --- a/kernel/trace/trace_output.c > > +++ b/kernel/trace/trace_output.c > > @@ -460,7 +460,7 @@ int trace_print_lat_fmt(struct trace_seq > > (entry->flags & TRACE_FLAG_IRQS_OFF && bh_off) ? 'D' : > > (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' : > > bh_off ? 'b' : > > - (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' : > > + !IS_ENABLED(CONFIG_TRACE_IRQFLAGS_SUPPORT) ? 'X' : > > Probably can even remove this check. Yes. > -- Steve Sebastian