From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: last_marked array is now ifdef'ed away Date: Tue, 17 Sep 2024 16:22:48 +0300 Message-ID: <86cyl2bejb.fsf@gnu.org> References: <86zfokyp64.fsf@gnu.org> <86ed5pkz53.fsf@gnu.org> <851C7C12-44A1-4661-9EA7-16B0B7209D11@gmail.com> <86a5gbk295.fsf@gnu.org> <8634m2f8ii.fsf@gnu.org> <86o74pea7k.fsf@gnu.org> <861q1ldmla.fsf@gnu.org> <9354266E-9F9E-430E-A862-2169A62C9F67@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="39098"; mail-complaints-to="usenet@ciao.gmane.io" Cc: emacs-devel@gnu.org, acorallo@gnu.org To: Mattias =?utf-8?Q?Engdeg=C3=A5rd?= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Tue Sep 17 15:23:43 2024 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1sqYBD-000A2A-8t for ged-emacs-devel@m.gmane-mx.org; Tue, 17 Sep 2024 15:23:43 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sqYAd-0002dE-UC; Tue, 17 Sep 2024 09:23:07 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sqYAY-0002cT-Jw for emacs-devel@gnu.org; Tue, 17 Sep 2024 09:23:05 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sqYAX-0000Kd-Ai; Tue, 17 Sep 2024 09:23:01 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=MIME-version:References:Subject:In-Reply-To:To:From: Date; bh=pOSOr4GIsXpKqudkrEornvnz9Cy7SxoZjXiuTYS6nRA=; b=RX+AGgUv49oCL+6nQYcI 9PExer3yv8sEoEZQrSZQCka1P5D9m0gVHa2k3ixLLs44SYasVh4JuDpIDnem83PkJvdZHVUp+LF21 QCV7pSqZ4RmQpjkiU6zvSyo4A53EvekTgpM5ES1LAcE6Z4ZqOyqKA7DRJKzFFrtlE1D4Eo5hjwXMY HojyZUyKp58ayIJ8q6fWWDs5xBy70/OGDQiIpBWfD6JNegfE+iWlX4M2GL99zyvI6F+fa6ugW2CXX DvS7b7+D2U/np/uYL6avCGyMyf/VCaOLUwmQ2Rsv9I5ShjPMForBRwHvE941gQXILx+TvUZzc1mAF w+rYDSeQmS3gUw==; In-Reply-To: <9354266E-9F9E-430E-A862-2169A62C9F67@gmail.com> (message from Mattias =?utf-8?Q?Engdeg=C3=A5rd?= on Tue, 17 Sep 2024 12:15:16 +0200) X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:323693 Archived-At: > From: Mattias Engdegård > Date: Tue, 17 Sep 2024 12:15:16 +0200 > Cc: emacs-devel@gnu.org, > Andrea Corallo > > 15 sep. 2024 kl. 16.21 skrev Eli Zaretskii : > > > There's no need for any evidence to keep the code which we always had. > > Well, we didn't have it in Emacs 29, so one might be excused for thinking it wasn't a strict necessity. Because it was silently disabled. This change should have been discussed in advance. > > That won't help because GC crashes are seldom if ever reproducible. > > So if the trace is off, the information is gone and cannot be > > recovered in practice. > > My experience is rather that in such cases the crash was already gone because there was no core dump or debugger attached anyway, but we then take the necessary steps to catch the bug next time – turn on core dumps (if possible), run with a debugger, enable checking, etc – and we always end up trapping the gremlin eventually. At least some (many?) users have core dumps available, even though current systems foolishly disable them by default. I see this all the time on debbugs: users report bugs and tell they have core files or the crashed Emacs in a debugger. > Anyway, I'm going to re-enable the mark trace buffer for the sake of development peace; since it's important to you, that's also worth something. I shall add a configuration option for disabling it, with its trade-off clearly documented, so that users can make an informed decision, but the buffer will be enabled by default. Thank you. Having a knob to disable it is fine, as long as the default is to have it enabled.