From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E0A20352C40; Thu, 29 Jan 2026 20:29:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.13 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769718591; cv=none; b=XN0k2F58OtB4eiXLowUxgSElypi7XpT7ix0lrQqUBnr0btuKHQTZ3TtdxLHkEZNCDZFmHjXRS4PXkx4jLgG28gOU585q48PGrCQRmxWQ0cCHmAH2GZUa9bj8TJrsuqc3SVnOOcgSl+Pj5Rad1yJNFK0CGpJL1epRo3tFfT4jPmo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769718591; c=relaxed/simple; bh=4qJbSptnmcF43KW9k9yEejbJpKYWg/JMhClRakopTQI=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=eVbQnHKsI7LckCPf6PmIgKcwbnlolyeSjyJQ/9ykYJvnyjFQ8sdYh12x+Nypdh2TKKidVdZZfwAluqg+tQakHaYQ3KyG9RfUlaqWryMcyjiQdl5AEW4+AJmYkhfsP5ruCphkxWJ5wkQzSdPE9wtroHTkI04SLZa7ldIfiCUtg1o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 4B0141A02E0; Thu, 29 Jan 2026 20:29:48 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf13.hostedemail.com (Postfix) with ESMTPA id 0C50320010; Thu, 29 Jan 2026 20:29:45 +0000 (UTC) Date: Thu, 29 Jan 2026 15:29:58 -0500 From: Steven Rostedt To: Jens Axboe Cc: Yaxiong Tian , mhiramat@kernel.org, mathieu.desnoyers@efficios.com, corbet@lwn.net, skhan@linuxfoundation.org, linux-trace-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH v4 5/5] blktrace: Make init_blk_tracer() asynchronous when trace_async_init set Message-ID: <20260129152958.05c1ca46@gandalf.local.home> In-Reply-To: <56C8934E-3D17-4467-93E6-D813770BF577@kernel.dk> References: <20260128194104.30051be1@gandalf.local.home> <56C8934E-3D17-4467-93E6-D813770BF577@kernel.dk> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) 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-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 0C50320010 X-Stat-Signature: b33d9fd4ichz7wyqqzjufmukuixmzmni X-Rspamd-Server: rspamout05 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX19qkA0wJOpiwjiiKOANYpARcGxp1NJrOCw= X-HE-Tag: 1769718585-900540 X-HE-Meta: U2FsdGVkX18NrxCl9h9TMLWr6AHyg4XoMaI4xsFj/zTKMfdNpCY1eMAjTIojzsFqilHKPXu6nzLw3efnC1YKbyCN8QRwd7HBONn2XrNuIGa3NsH7cf2+l3Ziq9pPI7riuNsWui6B1bqIpmRWlIqRcJWv29+PD2M9Y1aqpTdAvqVxryvIDcF7FKrJGnZEkDcs1IyUewHfMtBdQdOYmVPRiuF3vOUyabAzzUs8XtRwdK86jtCKk8yTofnohI/3LizIi+3Wpx7izDMU+bIvo1Pbu5teogmir4QLXasV7gnUrVCLqKToescXf9eAiIBXwi9TTkvTH8DDVqrn2nqar9F0PAToSB1aHyOtE17gIk8IgE8svr1vatd5f2FxSEKZzPoT On Wed, 28 Jan 2026 19:25:46 -0700 Jens Axboe wrote: > On Jan 28, 2026, at 5:40=E2=80=AFPM, Steven Rostedt = wrote: > >=20 > > =EF=BB=BF > > Jens, > >=20 > > Can you give me an acked-by on this patch and I can take the series thr= ough > > my tree. =20 >=20 > On phone, hope this works: >=20 > Acked-by: Jens Axboe Thanks! >=20 > > Or perhaps this doesn't even need to test the trace_async_init flag and= can > > always do the work queue? Does blk_trace ever do tracing at boot up? Th= at > > is, before user space starts? =20 >=20 > Not via the traditonal way of running blktrace. Masami and Yaxiong, I've been thinking about this more and I'm not sure we need the trace_async_init kernel parameter at all. As blktrace should only be enabled by user space, it can always use the work queue. For kprobes, if someone is adding a kprobe on the kernel command line, then they are already specifying that tracing is more important. Patch 3 already keeps kprobes from being an issue with contention of the tracing locks, so I don't think it ever needs to use the work queue. Wouldn't it just be better to remove the trace_async_init and make blktrace always use the work queue and kprobes never do it (but exit out early if there were no kprobes registered)? That is, remove patch 2 and 4 and make this patch always use the work queue. -- Steve