From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: [patch V2 01/29] tracing: Cleanup stack trace code Date: Thu, 18 Apr 2019 17:24:43 -0400 Message-ID: <20190418172443.30ec83e3@gandalf.local.home> References: <20190418084119.056416939@linutronix.de> <20190418084253.142712304@linutronix.de> <20190418135721.5vwd6ngxagrrrrtt@treble> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Thomas Gleixner Cc: Mike Snitzer , David Airlie , Catalin Marinas , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, dm-devel@redhat.com, Alexander Potapenko , Christoph Lameter , Christoph Hellwig , Alasdair Kergon , Marek Szyprowski , linux-arch@vger.kernel.org, x86@kernel.org, kasan-dev@googlegroups.com, Johannes Thumshirn , Andrey Ryabinin , Alexey Dobriyan , intel-gfx@lists.freedesktop.org, David Rientjes , Akinobu Mita , Josef Bacik , Mike Rapoport , Andy Lutomirski , Josh Poimboeuf , David Sterba , Dmitry Vyukov List-Id: linux-arch.vger.kernel.org T24gVGh1LCAxOCBBcHIgMjAxOSAyMzoxNDo0NSArMDIwMCAoQ0VTVCkKVGhvbWFzIEdsZWl4bmVy IDx0Z2x4QGxpbnV0cm9uaXguZGU+IHdyb3RlOgoKPiBPbiBUaHUsIDE4IEFwciAyMDE5LCBKb3No IFBvaW1ib2V1ZiB3cm90ZToKPiAKPiA+IE9uIFRodSwgQXByIDE4LCAyMDE5IGF0IDEwOjQxOjIw QU0gKzAyMDAsIFRob21hcyBHbGVpeG5lciB3cm90ZTogIAo+ID4gPiAtIFJlbW92ZSB0aGUgZXh0 cmEgYXJyYXkgbWVtYmVyIG9mIHN0YWNrX2R1bXBfdHJhY2VbXS4gSXQncyBub3QgcmVxdWlyZWQg YXMKPiA+ID4gICB0aGUgc3RhY2sgdHJhY2VyIHN0b3JlcyBhdCBtYXggYXJyYXkgc2l6ZSAtIDEg ZW50cmllcyBzbyB0aGVyZSBpcyBzdGlsbAo+ID4gPiAgIGFuIGVtcHR5IHNsb3QuICAKPiA+IAo+ ID4gV2hhdCBpcyB0aGUgZW1wdHkgc2xvdCB1c2VkIGZvcj8gIAo+IAo+IEkgd2FzIHRyeWluZyB0 byBmaW5kIGFuIGFuc3dlciBidXQgZmFpbGVkLiBNYXliZSBpdCdzIGp1c3QgaGlzdG9yaWNhbAo+ IGxlZnRvdmVycyBvciBTdGV2ZW4ga25vd3Mgd2hlcmUgdGhlIG1hZ2ljIGlzIGluIHRoaXMgbWF6 ZS4KPgoKSSBiZWxpZXZlIGl0IHdhcyBmb3IgaGlzdG9yaWNhbCBsZWZ0b3ZlcnMgKHRoZXJlIHdh cyBhIHRpbWUgaXQgd2FzCnJlcXVpcmVkKSwgYW5kIGxlZnQgdGhlcmUgZm9yICJwYXJhbm9pZCIg c2FrZS4gQnV0IGxldCBtZSBhcHBseSB0aGUKcGF0Y2ggYW5kIHNlZSBpZiBpdCBpcyByZWFsbHkg bmVlZGVkLgoKLS0gU3RldmUKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX18KSW50ZWwtZ2Z4IG1haWxpbmcgbGlzdApJbnRlbC1nZnhAbGlzdHMuZnJlZWRlc2t0 b3Aub3JnCmh0dHBzOi8vbGlzdHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8vaW50 ZWwtZ2Z4 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:42386 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728264AbfDRVYt (ORCPT ); Thu, 18 Apr 2019 17:24:49 -0400 Date: Thu, 18 Apr 2019 17:24:43 -0400 From: Steven Rostedt Subject: Re: [patch V2 01/29] tracing: Cleanup stack trace code Message-ID: <20190418172443.30ec83e3@gandalf.local.home> In-Reply-To: References: <20190418084119.056416939@linutronix.de> <20190418084253.142712304@linutronix.de> <20190418135721.5vwd6ngxagrrrrtt@treble> 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: Josh Poimboeuf , LKML , 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: <20190418212443.MLsQBB9Z7Q-Bj_57FVtCWgi2jk6xZQVROJEZqeokrKc@z> On Thu, 18 Apr 2019 23:14:45 +0200 (CEST) Thomas Gleixner wrote: > On Thu, 18 Apr 2019, Josh Poimboeuf wrote: > > > On Thu, Apr 18, 2019 at 10:41:20AM +0200, Thomas Gleixner wrote: > > > - Remove the extra array member of stack_dump_trace[]. It's not required as > > > the stack tracer stores at max array size - 1 entries so there is still > > > an empty slot. > > > > What is the empty slot used for? > > I was trying to find an answer but failed. Maybe it's just historical > leftovers or Steven knows where the magic is in this maze. > I believe it was for historical leftovers (there was a time it was required), and left there for "paranoid" sake. But let me apply the patch and see if it is really needed. -- Steve