From owner-freebsd-stable@freebsd.org Sat Jul 22 07:41:24 2017 Return-Path: Delivered-To: freebsd-stable@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id A3039CFE20A for ; Sat, 22 Jul 2017 07:41:24 +0000 (UTC) (envelope-from eugen@grosbein.net) Received: from hz.grosbein.net (hz.grosbein.net [78.47.246.247]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "hz.grosbein.net", Issuer "hz.grosbein.net" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 3A2FC7020C; Sat, 22 Jul 2017 07:41:23 +0000 (UTC) (envelope-from eugen@grosbein.net) Received: from eg.sd.rdtc.ru (root@eg.sd.rdtc.ru [62.231.161.221]) by hz.grosbein.net (8.15.2/8.15.2) with ESMTPS id v6M7fEB6027054 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sat, 22 Jul 2017 09:41:15 +0200 (CEST) (envelope-from eugen@grosbein.net) X-Envelope-From: eugen@grosbein.net X-Envelope-To: kostikbel@gmail.com Received: from [10.58.0.4] ([10.58.0.4]) by eg.sd.rdtc.ru (8.15.2/8.15.2) with ESMTPS id v6M7f4tI091237 (version=TLSv1.2 cipher=DHE-RSA-AES128-SHA bits=128 verify=NOT); Sat, 22 Jul 2017 14:41:04 +0700 (+07) (envelope-from eugen@grosbein.net) Subject: Re: stable/11 r321349 crashing immediately To: Konstantin Belousov References: <201707220542.v6M5ggtP052112@gw.catspoiler.org> <5972E7C5.6070102@grosbein.net> <20170722070529.GP1935@kib.kiev.ua> Cc: Don Lewis , pz-freebsd-stable@ziemba.us, freebsd-stable@FreeBSD.org From: Eugene Grosbein Message-ID: <5973018B.2050505@grosbein.net> Date: Sat, 22 Jul 2017 14:40:59 +0700 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: <20170722070529.GP1935@kib.kiev.ua> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=0.3 required=5.0 tests=BAYES_00,LOCAL_FROM autolearn=no autolearn_force=no version=3.4.1 X-Spam-Report: * -2.3 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0000] * 2.6 LOCAL_FROM From my domains X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on hz.grosbein.net X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 22 Jul 2017 07:41:24 -0000 22.07.2017 14:05, Konstantin Belousov wrote: > On Sat, Jul 22, 2017 at 12:51:01PM +0700, Eugene Grosbein wrote: >> Also, there is https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=219476 > > I strongly disagree with the idea of increasing the default kernel > stack size, it will cause systematic problems for all users instead of > current state where some workloads are problematic. Finding contig > KVA ranges for larger stacks on KVA-starved architectures is not going > to work. My practice shows that increase of default kernel stack size for i386 system using IPSEC and ZFS with compression and KVA_PAGES=512/KSTACK_PAGES=4 does work. No stack-relates problems observed with such parametes. Contrary, problems quickly arise if one does not increase default kernel stack size for such i386 system. I use several such systems for years. We have src/UPDATING entries 20121223 and 20150728 stating the same. Those are linked to Errata Notes to every release since 10.2 as open issues. How many releases are we going to keep this "open"? Also, I've always wondered what load pattern one should have to exhibit real kernel stack problems due to KVA fragmentation and KSTACK_PAGES>2 on i386? > The real solution is to move allocations from stack to heap, one by one. That was not done since 10.2-RELEASE and I see that this only getting worse. > You claimed that vm/vm_object.o consumes 1.5K of stack, can you show > the ddb backtrace of this situation ? These data were collected with machine object code inspection and only some of numbers were verified by hand. I admit there may be some false positives. How can I get ddb backtrace you asked for? I'm not very familiar with ddb. I have serial console to such i386 system.