From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E6D1EC433F5 for ; Fri, 14 Jan 2022 11:54:11 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7DB0E10E144; Fri, 14 Jan 2022 11:54:10 +0000 (UTC) X-Greylist: delayed 431 seconds by postgrey-1.36 at gabe; Fri, 14 Jan 2022 11:54:07 UTC Received: from smtp2.axis.com (smtp2.axis.com [195.60.68.18]) by gabe.freedesktop.org (Postfix) with ESMTPS id BCF8010E13A; Fri, 14 Jan 2022 11:54:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=axis.com; q=dns/txt; s=axis-central1; t=1642161248; x=1673697248; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=AMs+u9nkmpDZ5lxA/fLhYjA5QxFXQFce1TTDfia+q9o=; b=BwnurFI7TWdUrKvcHbOtcOxy6j66lWHbOY25eFyI7MGQ16S7Ofa9uyUw bBUz9a9+r7UuIExfqKaIaXSVAN5E5tYg7Wku7GC44+9rj0X8QwffSE3B9 RMpYq2uX5eGW2CHnRm/rqnN/n95eJKaom5cFT3zQQq8RDXA/5bGJHj1t3 qjoxC56I0hBLhu4lBYEPC1/1baWAOEAuuS9mwYltDRfl2w9OXZx9zeuCL P2I58Bswrn8mPnZYSHUNWUVrL3WoFf/4z64G8SycEl5HAio6FUzfQMUaP 0go8S0UZVavRw0l0w5QAp1ewoU2PjODMGxnEKWolr1h8KIELBITe9I0AW Q==; Date: Fri, 14 Jan 2022 12:46:54 +0100 From: Vincent Whitchurch To: Jim Cromie Subject: Re: [PATCH v11 03/19] dyndbg: add write-to-tracefs code Message-ID: <20220114114654.GA23983@axis.com> References: <20220107052942.1349447-1-jim.cromie@gmail.com> <20220107052942.1349447-4-jim.cromie@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20220107052942.1349447-4-jim.cromie@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "quic_saipraka@quicinc.com" , "catalin.marinas@arm.com" , "linux@rasmusvillemoes.dk" , "dri-devel@lists.freedesktop.org" , "will@kernel.org" , "maz@kernel.org" , "amd-gfx@lists.freedesktop.org" , "mingo@redhat.com" , "daniel.vetter@ffwll.ch" , "arnd@arndb.de" , "linux-arm-msm@vger.kernel.org" , "intel-gfx@lists.freedesktop.org" , "rostedt@goodmis.org" , "jbaron@akamai.com" , "mathieu.desnoyers@efficios.com" , "intel-gvt-dev@lists.freedesktop.org" , "linux-arm-kernel@lists.infradead.org" , "gregkh@linuxfoundation.org" , "linux-kernel@vger.kernel.org" , "quic_psodagud@quicinc.com" , "seanpaul@chromium.org" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Fri, Jan 07, 2022 at 06:29:26AM +0100, Jim Cromie wrote: > adds: dynamic_trace() > uses trace_console() temporarily to issue printk:console event > uses internal-ish __ftrace_trace_stack code: > 4-context buffer stack, barriers per Steve > > call it from new funcs: > dynamic_printk() - print to both syslog/tracefs > dynamic_dev_printk() - dev-print to both syslog/tracefs > > These handle both _DPRINTK_FLAGS_PRINTK and _DPRINTK_FLAGS_TRACE > cases, allowing to vsnprintf the message once and use it for both, > skipping past the KERN_DEBUG character for tracing. > > Finally, adjust the callers: __dynamic_{pr_debug,{,net,ib}dev_dbg}, > replacing printk and dev_printk with the new funcs above. > > The _DPRINTK_FLAGS_TRACE flag character s 'T', so the following finds > all callsites enabled for tracing: > > grep -P =p?T /proc/dynamic_debug/control > > Enabling debug-to-tracefs is 2 steps: > > # event enable > echo 1 > /sys/kernel/tracing/events/dyndbg/enable > # callsite enable > echo module foo +T > /proc/dynamic_debug/control > > This patch,~1,~2 are based upon: > https://lore.kernel.org/lkml/20200825153338.17061-1-vincent.whitchurch@axis.com/ > > .. with simplification of temporarily reusing trace_console() rather > than adding a new printk:dyndbg event. Soon, add 2 new events > capturing the pr_debug & dev_dbg() args. The example above does not match the code in this patch since the dyndbg:* events are only added in a later patch. Perhaps you could reorder this patch stack so that you don't use trace_console() in this patch just to replace it with the new events in the next patch? > > CC: vincent.whitchurch@axis.com > Signed-off-by: Jim Cromie > --- > .../admin-guide/dynamic-debug-howto.rst | 1 + > lib/dynamic_debug.c | 155 +++++++++++++++--- > 2 files changed, 130 insertions(+), 26 deletions(-) > > diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst [...] > @@ -723,29 +822,33 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, > { > struct va_format vaf; > va_list args; > + unsigned int flags; > > va_start(args, fmt); > > vaf.fmt = fmt; > vaf.va = &args; > + flags = descriptor->flags; > > if (ibdev && ibdev->dev.parent) { > char buf[PREFIX_SIZE] = ""; > > - dev_printk_emit(LOGLEVEL_DEBUG, ibdev->dev.parent, > - "%s%s %s %s: %pV", > - dynamic_emit_prefix(descriptor, buf), > - dev_driver_string(ibdev->dev.parent), > - dev_name(ibdev->dev.parent), > - dev_name(&ibdev->dev), > - &vaf); > + dynamic_dev_printk(flags, ibdev->dev.parent, > + "%s%s %s %s: %pV", > + dynamic_emit_prefix(descriptor, buf), > + dev_driver_string(ibdev->dev.parent), > + dev_name(ibdev->dev.parent), > + dev_name(&ibdev->dev), > + &vaf); > } else if (ibdev) { > - printk(KERN_DEBUG "%s: %pV", dev_name(&ibdev->dev), &vaf); > + dynamic_printk(flags, KERN_DEBUG "%s%s: %pV", > + dev_name(&ibdev->dev), &vaf); > } else { > - printk(KERN_DEBUG "(NULL ib_device): %pV", &vaf); > + dynamic_printk(flags, KERN_DEBUG "(NULL ip_device): %pV", > + &vaf); > } > > - va_end(args); > +va_end(args); This looks like an unintentional whitespace change?