From owner-freebsd-stable@FreeBSD.ORG Wed Aug 28 22:07:00 2013 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 4A3FD2B4 for ; Wed, 28 Aug 2013 22:07:00 +0000 (UTC) (envelope-from robert.burmeister@utoledo.edu) Received: from sam.nabble.com (sam.nabble.com [216.139.236.26]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 2AC9A2B2B for ; Wed, 28 Aug 2013 22:06:59 +0000 (UTC) Received: from [192.168.236.26] (helo=sam.nabble.com) by sam.nabble.com with esmtp (Exim 4.72) (envelope-from ) id 1VEntD-0005MS-4a for freebsd-stable@freebsd.org; Wed, 28 Aug 2013 15:06:59 -0700 Date: Wed, 28 Aug 2013 15:06:59 -0700 (PDT) From: Robert_Burmeister To: freebsd-stable@freebsd.org Message-ID: <1377727619133-5839769.post@n5.nabble.com> In-Reply-To: References: <521C9E85.4060801@UToledo.edu> <521D7552.5080008@UToledo.edu> Subject: Re: Suggest changing dirhash defaults for FreeBSD 9.2. MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 28 Aug 2013 22:07:00 -0000 Ivan Voras-7 wrote > On 28/08/2013 05:58, Robert Burmeister wrote: >> >> On 8/27/2013 9:40 AM, Sergey Kandaurov wrote: >>> On 27 August 2013 16:41, Robert Burmeister >>> < > Robert.Burmeister@ > > wrote: >>>> I believe that increasing the following values by 10 would benefit >>>> most FreeBSD users without disadvantage. >>>> vfs.ufs.dirhash_maxmem: 2097152 to 20971520 >>>> vfs.ufs.dirhash_reclaimage: 5 to 50 or 60 > > I'll bump vfs.ufs.dirhash_reclaimage to 60, it's worth it. Note that vfs.ufs.dirhash_reclaimage is not used to shield ufs_dirhashmem entries, rather all entries older than reclaimage are evicted from the cache on vm_lowmem before evicting a percentage of the oldest remaining entries. If it has been hours since a kernel vm_lowmem event, most of the entries in the cache can be lost due to a momentary memory spike. Also note, under kernel memory pressure continuous vm_lowmem events will effectively extinguish the ufs_dirhash cache, returning its memory to the kernel. I believe this prevents the ufsdirhash cache from in any way contributing to a kernel panic, so bumping vfs.ufs.dirhash_reclaimage to 60 should be riskless. -- View this message in context: http://freebsd.1045724.n5.nabble.com/Suggest-changing-dirhash-defaults-for-FreeBSD-9-2-tp5839351p5839769.html Sent from the freebsd-stable mailing list archive at Nabble.com.