From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 42BB142981A for ; Wed, 21 Jan 2026 14:56:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769007389; cv=none; b=iaaLt63J+hpNXxRC7WrVqZKa4n5EdJJSIv+LLZ8Zydn1zjd4pqC0UIP6dtTHwvNWNLr97OJsrfy6hDkye/9WIDQH9HYKTgqUcl707ont6r2/cL2sOIsYkttCQDbS+lAOvqbLj75153RvWbS8elAIUvn/u2tBJteNjDmqa8XRjn4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769007389; c=relaxed/simple; bh=j+Qxr/WnIT3OJZ8m6GRBgrRI/8t0Bs+7c7F9UCSCMP4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=b/rcUBfhOsqlxEk6QmmsI4TNveg8pJn0/sCWZAEvd4Jq0h78/roN/zwgPH6dIdqW3/a8I+eE8V+1sMs/qAU8yk2bs961h8u0sBA1P/1OUv59MK62oK2O5uxfBHA8MEClPW8kBwgYTEuE9G24wCJSS5EZHquSLoKX0I8iOyVVkAE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=YYFNiD9B; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="YYFNiD9B" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=W0Z25jwKWwyMR2jUm4j//BVRm86j1Donlgmn/Yew920=; b=YYFNiD9B0oe4tt62OVRRoO3WiB 0D5nqbXPv/SWl/zm9QTnIfl/x3DGhL6mZD2VrVUDxWa5F61NSGyAJfPeoDgVHJhOOP7yEIERe/GNx 75138skPQdi9WFUhZhBnDkTGHMX/Np+iOmUK4p/ogASq9sA/oPwZsNzIEyE/Q0fTLGuulzge3a6lt +1WwevTXXwMtBIV7pAY9a7IkNU8Kb/+WgyC6D4qO+W04foJGjqCgqM8gW1SqET/twzc0zum/Pufmn tqECilYieTbKuptNYvAWmytv8puPJm/uRAg84fKWmz+Z/1UOAryz0OaFjEUr/nV/l46aLBPWr1ss9 9T0o5iRg==; Received: from 2001-1c00-8d85-5700-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d85:5700:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1viZd2-0000000GFWz-2Lqk; Wed, 21 Jan 2026 14:56:16 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 16824300B8A; Wed, 21 Jan 2026 15:56:16 +0100 (CET) Date: Wed, 21 Jan 2026 15:56:16 +0100 From: Peter Zijlstra To: Thomas =?iso-8859-1?Q?Wei=DFschuh?= Cc: tglx@linutronix.de, mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org, paulmck@kernel.org, boqun.feng@gmail.com, corbet@lwn.net, prakash.sangappa@oracle.com, vineethr@linux.ibm.com, kprateek.nayak@amd.com, rostedt@goodmis.org, bigeasy@linutronix.de, arnd@arndb.de, rdunlap@infradead.org, rongevarg@gmail.com, longman@redhat.com Subject: Re: [PATCH 2/5] rseq: Move slice_ext_nsec to debugfs Message-ID: <20260121145616.GD166857@noisy.programming.kicks-ass.net> References: <20260121142457.242071831@infradead.org> <20260121143207.923520192@infradead.org> <20260121154225-d38a4029-6ad9-4a83-926e-c83b6af49ac6@linutronix.de> 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=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260121154225-d38a4029-6ad9-4a83-926e-c83b6af49ac6@linutronix.de> On Wed, Jan 21, 2026 at 03:50:55PM +0100, Thomas Weißschuh wrote: > On Wed, Jan 21, 2026 at 03:24:59PM +0100, Peter Zijlstra wrote: > > Move changing the slice ext duration to debugfs, a sliglty less permanent > > interface. > > > > Signed-off-by: Peter Zijlstra (Intel) > > --- > > (...) > > > --- a/kernel/rseq.c > > +++ b/kernel/rseq.c > > @@ -222,12 +222,16 @@ static const struct file_operations debu > > .release = single_release, > > }; > > > > +extern void rseq_slice_ext_init(struct dentry *root_dir); > > This is actually a static function. Yes, but it is not always defined. > > + > > static int __init rseq_debugfs_init(void) > > { > > struct dentry *root_dir = debugfs_create_dir("rseq", NULL); > > > > debugfs_create_file("debug", 0644, root_dir, NULL, &debug_ops); > > rseq_stats_init(root_dir); > > + if (IS_ENABLED(CONFIG_RSEQ_SLICE_EXTENSIO)) > > Missing 'N' at the end. Argh. Some day my editor will tell me this :/ > > + rseq_slice_ext_init(root_dir); > > return 0; > > } > > __initcall(rseq_debugfs_init); > > @@ -515,7 +519,9 @@ struct slice_timer { > > void *cookie; > > }; > > (...) > > > +#ifdef CONFIG_DEBUG_FS > > (...) > > > +#else > > +static void rseq_slice_ext_init(struct dentry *root_dir) { } > > +#endif > > It might be possible to just remove the CONFIG_DEBUG_FS ifdeffery and let the > compiler optimize away all of the debugfs-related code automatically. I'll check.