From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: [patch V2 21/29] tracing: Use percpu stack trace buffer more intelligently Date: Thu, 18 Apr 2019 11:46:29 -0400 Message-ID: <20190418114629.023b63d7@gandalf.local.home> References: <20190418084119.056416939@linutronix.de> <20190418084254.999521114@linutronix.de> <20190418105334.5093528d@gandalf.local.home> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Thomas Gleixner Cc: LKML , Josh Poimboeuf , x86@kernel.org, Andy Lutomirski , Alexander Potapenko , Alexey Dobriyan , Andrew Morton , Pekka Enberg , linux-mm@kvack.org, David Rientjes , Christoph Lameter , Catalin Marinas , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, Mike Rapoport , Akinobu Mita , iommu@lists.linux-foundation.org, Robin Murphy , Christoph Hellwig , Marek Szyprowski List-Id: linux-arch.vger.kernel.org On Thu, 18 Apr 2019 17:43:59 +0200 (CEST) Thomas Gleixner wrote: > On Thu, 18 Apr 2019, Steven Rostedt wrote: > > On Thu, 18 Apr 2019 10:41:40 +0200 > > Thomas Gleixner wrote: > > > -static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack); > > > +/* This allows 8 level nesting which is plenty */ > > > > Can we make this 4 level nesting and increase the size? (I can see us > > going more than 64 deep, kernel developers never cease to amaze me ;-) > > That's all we need: > > > > Context: Normal, softirq, irq, NMI > > > > Is there any other way to nest? > > Not that I know, but you are the tracer dude :) > There's other places I only test 4 deep, so it should be fine to limit it to 4 then. Thanks! -- Steve From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:43132 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387519AbfDRPqf (ORCPT ); Thu, 18 Apr 2019 11:46:35 -0400 Date: Thu, 18 Apr 2019 11:46:29 -0400 From: Steven Rostedt Subject: Re: [patch V2 21/29] tracing: Use percpu stack trace buffer more intelligently Message-ID: <20190418114629.023b63d7@gandalf.local.home> In-Reply-To: References: <20190418084119.056416939@linutronix.de> <20190418084254.999521114@linutronix.de> <20190418105334.5093528d@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Thomas Gleixner Cc: LKML , Josh Poimboeuf , x86@kernel.org, Andy Lutomirski , Alexander Potapenko , Alexey Dobriyan , Andrew Morton , Pekka Enberg , linux-mm@kvack.org, David Rientjes , Christoph Lameter , Catalin Marinas , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, Mike Rapoport , Akinobu Mita , iommu@lists.linux-foundation.org, Robin Murphy , Christoph Hellwig , Marek Szyprowski , Johannes Thumshirn , David Sterba , Chris Mason , Josef Bacik , linux-btrfs@vger.kernel.org, dm-devel@redhat.com, Mike Snitzer , Alasdair Kergon , intel-gfx@lists.freedesktop.org, Joonas Lahtinen , Maarten Lankhorst , dri-devel@lists.freedesktop.org, David Airlie , Jani Nikula , Daniel Vetter , Rodrigo Vivi , linux-arch@vger.kernel.org Message-ID: <20190418154629.BMo27cb3IoiS4O3GQ_jjJXFbmJuKs7S5613tv1tohoQ@z> On Thu, 18 Apr 2019 17:43:59 +0200 (CEST) Thomas Gleixner wrote: > On Thu, 18 Apr 2019, Steven Rostedt wrote: > > On Thu, 18 Apr 2019 10:41:40 +0200 > > Thomas Gleixner wrote: > > > -static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack); > > > +/* This allows 8 level nesting which is plenty */ > > > > Can we make this 4 level nesting and increase the size? (I can see us > > going more than 64 deep, kernel developers never cease to amaze me ;-) > > That's all we need: > > > > Context: Normal, softirq, irq, NMI > > > > Is there any other way to nest? > > Not that I know, but you are the tracer dude :) > There's other places I only test 4 deep, so it should be fine to limit it to 4 then. Thanks! -- Steve