From owner-svn-src-head@freebsd.org Thu Aug 27 16:28:21 2015 Return-Path: Delivered-To: svn-src-head@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 3DBFA9C42C8 for ; Thu, 27 Aug 2015 16:28:21 +0000 (UTC) (envelope-from julien@jch.io) Received: from mail-qk0-f169.google.com (mail-qk0-f169.google.com [209.85.220.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id F033139C for ; Thu, 27 Aug 2015 16:28:20 +0000 (UTC) (envelope-from julien@jch.io) Received: by qkfh127 with SMTP id h127so13336165qkf.1 for ; Thu, 27 Aug 2015 09:28:14 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:to:references:cc:from:message-id:date :user-agent:mime-version:in-reply-to:content-type; bh=IR4EwaeRQY5W/I2jyuIwuNTNbsCvxfoeeqjWGveDMqY=; b=LBGN5H3gSlKrm7FQZPWhndbKWAg5p6wXpuSYKBpkJZonNwYhGvCcw9ym5H6/9GUI7k LxW56lzptdrZHjRhtEJL6KTWkGvPqT3+GDO1OsbRRc1/n8/Nl5D0SdsIDYH+KGngsKQS zLAXD+39uXZtsSkjBLC0IA7JD3I5UDQ9oaoQwzFXuJTWonwcyB5DNKaVoCEUbhdvxN3A FIMe/ZiCPqfTH8xge0Toiqu7kFn9fuup34m9Fgu/yospZu/M5hqUTYU4OCkLn2dQaAsY 3BhmAsww/8l6PkTohyXGx0oMABLR1K7U7rqIYNbB1x46lIWpIDBlcdoMfNZh710yqbx2 yZYg== X-Gm-Message-State: ALoCoQnhGplt57o/IL4PF0oEcTunHzGhSdTZBWtXo8jtCA8ogypj+LywNvHxAcFe5NBCQDCqnoMX X-Received: by 10.55.25.39 with SMTP id k39mr8011991qkh.3.1440692894590; Thu, 27 Aug 2015 09:28:14 -0700 (PDT) Received: from FRI2JCHARBON-M1.local (h87.s239.verisign.com. [216.168.239.87]) by smtp.googlemail.com with ESMTPSA id s90sm1516267qki.46.2015.08.27.09.28.11 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 27 Aug 2015 09:28:13 -0700 (PDT) Subject: Re: svn commit: r286880 - head/sys/kern To: Konstantin Belousov References: <201508181015.t7IAFAex055889@repo.freebsd.org> <55DD69E5.4090904@selasky.org> <55DD74EB.30601@selasky.org> <55DE01F7.8040508@freebsd.org> <20150827104946.GH2072@kib.kiev.ua> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, John Baldwin From: Julien Charbon X-Enigmail-Draft-Status: N1110 Message-ID: <55DF3A93.8080507@freebsd.org> Date: Thu, 27 Aug 2015 18:28:03 +0200 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20150827104946.GH2072@kib.kiev.ua> Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="SVS6NPqis9EGM4UjCbJLup9A4J7fHAD6T" X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 27 Aug 2015 16:28:21 -0000 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --SVS6NPqis9EGM4UjCbJLup9A4J7fHAD6T Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Hi Konstantin, On 27/08/15 12:49, Konstantin Belousov wrote: > On Wed, Aug 26, 2015 at 08:14:15PM +0200, Julien Charbon wrote: >> As I said, I am not opposed to back out this change, callout(9) API i= n >> mpsafe mode is a already complex/subtle API, it won't change too much >> the current complexity. >> >> Let say that if nobody screams until Friday 8/28, I will put back >> r284245 and revert this change _and_ I will make this case clear in th= e >> man page. >=20 > [Replying to a random message in the whole set of conversations] >=20 > There is one more case, besides TCP timers, which is equially, of not > more, critical and sensitive WRT to the callout_stop(). Look at the > sys/kern/subr_sleepqueue.c:sleepq_check_timeout(). Stray return of > the false result from callout_stop() causes creation of the non-killabl= e > processes: the callout fired, we missed the wakeup and went to sleep > by manually doing the context switch. Such thread cannot be woken up. >=20 > I suspect that your fix is a better approach than my attempt to look > at something similar at PR 200992 (may be not). This change (r286880) won't improve the PR 200992: r286880 only addresses a case where callout_stop() returns 1 instead of 0. Thus the only thing that can do r286880 to PR 200992: - Don't change anything the issues - Worsen the issue Sorry to kill your hope of a simple and elegant fix for PR 200992. -- Julien --SVS6NPqis9EGM4UjCbJLup9A4J7fHAD6T Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQEcBAEBCgAGBQJV3zqZAAoJEKVlQ5Je6dhx8VIIAOHAgwFW0zb381yUbXDkyPmV EldTc+OgznnnB3MblbC0kyxBOI+rxgo1S0cOldzMNtiK+Cf2YYQDsRp6rwgu8aVg CgGsGAMXAsA3BCJvHzjb57JOOBRMVJ5Q5+qjpRykzOkDeaX9UXiF6m/XmKx79DMM 5+mDWz6GlJlnTRZN/iZrQAR2PdBR0ebpw2egSE+EXPmcwa5DApRY06hvSbTUNfYs XVblS7HYmCGzQw5Dz2VsSDoBXV3jrbYrrSZepIA/s9SB+ez0XbfKBQT8XAYXJg6g OJSn+0Ef+jgFRcGC+4h9RMUAga2MJH+EwjAr+l+Mq2OwI8Q5LKpQenkPC75z1B4= =HDgT -----END PGP SIGNATURE----- --SVS6NPqis9EGM4UjCbJLup9A4J7fHAD6T--