From owner-freebsd-hackers@FreeBSD.ORG Thu Sep 16 07:54:19 2010 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 292FA1065673 for ; Thu, 16 Sep 2010 07:54:19 +0000 (UTC) (envelope-from cronfy@gmail.com) Received: from mail-bw0-f54.google.com (mail-bw0-f54.google.com [209.85.214.54]) by mx1.freebsd.org (Postfix) with ESMTP id 828AB8FC1B for ; Thu, 16 Sep 2010 07:54:18 +0000 (UTC) Received: by bwz15 with SMTP id 15so1692964bwz.13 for ; Thu, 16 Sep 2010 00:54:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:mime-version:received:in-reply-to :references:from:date:message-id:subject:to:cc:content-type :content-transfer-encoding; bh=OYHEdS863mPnBUZrwgDQFTXSraAuIWi8EB+7DDTN0Lo=; b=jnVYTQYFL7fiuHbzo84ckt3cSxArUrYUejMpKRxHuWQmT1MlH/12wCFkFw7lSKxIj9 To/tcLuUC4fB1yIKjobXZasTcKllZ8sh9ItqZl+LlkHIWWBxgfXETxcPxU8Mlx1wayTb ZEvt6yjhs/CPilWBlOm29SgIpqiUIsdsUJx6s= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=ILpALBYbfO1m0sLFVOjl6RMBzr8bFUFBjsBIu04Q+tbR4yNa0fjX/2u5BIcARLzbKo qlJD/1uK4DbgmVT2FHI9VGlv9VBFCMn/I0r8Ubcg+LBYl4KsZknA068T4lEm0uUu7up3 /ET5wEXpdpPwGifwlZJRx9oJeUP5F68t01sPs= Received: by 10.204.82.18 with SMTP id z18mr2231732bkk.125.1284623657408; Thu, 16 Sep 2010 00:54:17 -0700 (PDT) MIME-Version: 1.0 Received: by 10.204.99.197 with HTTP; Thu, 16 Sep 2010 00:53:47 -0700 (PDT) In-Reply-To: <201009151509.49728.jhb@freebsd.org> References: <201009151509.49728.jhb@freebsd.org> From: cronfy Date: Thu, 16 Sep 2010 11:53:47 +0400 Message-ID: To: freebsd-hackers@freebsd.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: Subject: Re: is vfs.lookup_shared unsafe in 7.3? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 16 Sep 2010 07:54:19 -0000 >> Hello, >> >> Trying to overtake high server load (sudden peaks of 15%us/85%sy, LA > >> 40, very slow lstat() at these moments, looks like some kind of lock >> contention) I enabled vfs.lookup_shared=3D1 on two servers today. One is >> FreeBSD-7.3 kernel csup'ed and built Sep =A09 2010 and other is >> FreeBSD-7.3 csup'ed and built Jul 16 2010. >> >> The server with more fresh kernel is running nice and does not show >> high load anymore. But on the second server it did not help. More, >> after a few hours of work with vfs.lookup_shared=3D1 I noticed processes >> stucked in "ufs" state. I tried to kill them with no luck. Disabling >> vfs.lookup_shared freezed the whole system. >> >> So, is vfs.lookup_shared=3D1 unsafe in 7.3? Did it become more stable >> between 16 Jul and 9 Sep (is it the reason why first system is still >> running?), or should I expect that it will freeze in a near time too? >> >> Thanks in advance! > > No, 7.3 has a bug that can cause these hangs that is probably made worse = by > vfs.lookup_shared=3D1, but can occur even if it is disabled. =A0You want > these fixes applied (in order, one of them reverts part of another): Thank you for the fix and for the explanation, that's exactly what I wanted to know. Just to be sure: do these patches completely fix the bug with hangs (even without vfs.lookup_shared=3D1)? --=20 // cronfy