From owner-freebsd-current@freebsd.org Thu May 21 10:14:37 2020 Return-Path: Delivered-To: freebsd-current@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id AAF0032FE42 for ; Thu, 21 May 2020 10:14:37 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 49SQTT27sQz4hfN; Thu, 21 May 2020 10:14:36 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from tom.home (kib@localhost [127.0.0.1]) by kib.kiev.ua (8.15.2/8.15.2) with ESMTPS id 04LAETP2027910 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Thu, 21 May 2020 13:14:32 +0300 (EEST) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua 04LAETP2027910 Received: (from kostik@localhost) by tom.home (8.15.2/8.15.2/Submit) id 04LAESks027909; Thu, 21 May 2020 13:14:28 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Thu, 21 May 2020 13:14:28 +0300 From: Konstantin Belousov To: Ryan Libby Cc: Rick Macklem , "freebsd-current@FreeBSD.org" , Konstantin Belousov Subject: Re: r358252 causes intermittent hangs where processes are stuck sleeping on btalloc Message-ID: <20200521101428.GC64045@kib.kiev.ua> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FORGED_GMAIL_RCVD,FREEMAIL_FROM, NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on tom.home X-Rspamd-Queue-Id: 49SQTT27sQz4hfN X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:6939, ipnet:2001:470::/32, country:US] X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 21 May 2020 10:14:37 -0000 On Wed, May 20, 2020 at 11:58:50PM -0700, Ryan Libby wrote: > On Wed, May 20, 2020 at 6:04 PM Rick Macklem wrote: > > > > Hi, > > > > Since I hadn't upgraded a kernel through the winter, it took me a while > > to bisect this, but r358252 seems to be the culprit. > > > > If I do a kernel build over NFS using my not so big Pentium 4 (single core, > > 1.25Gbytes RAM, i386), about every second attempt will hang. > > When I do a "ps" in the debugger, I see processes sleeping on btalloc. > > If I revert to r358251, I cannot reproduce this. > > > > Any ideas? > > > > I can easily test any change you might suggest to see if it fixes the > > problem. > > > > If you want more debug info, let me know, since I can easily > > reproduce it. > > > > Thanks, rick > > Nothing obvious to me. I can maybe try a repro on a VM... > > ddb ps, acttrace, alltrace, show all vmem, show page would be welcome. > > "btalloc" is "We're either out of address space or lost a fill race." Yes, I would be not surprised to be out of something on 1G i386 machine. Please also add 'show alllocks'.