From owner-freebsd-stable@freebsd.org Thu Oct 13 09:59:53 2016 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 DBF39C0EADC for ; Thu, 13 Oct 2016 09:59:53 +0000 (UTC) (envelope-from petefrench@ingresso.co.uk) Received: from constantine.ingresso.co.uk (ingresso-1-pt.tunnel.tserv1.lon2.ipv6.he.net [IPv6:2001:470:1f1c:411::2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id AAB0D227 for ; Thu, 13 Oct 2016 09:59:53 +0000 (UTC) (envelope-from petefrench@ingresso.co.uk) Received: from dilbert.london-internal.ingresso.co.uk ([10.64.50.6]) by constantine.ingresso.co.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.87 (FreeBSD)) (envelope-from ) id 1bucnn-000EIS-MZ for freebsd-stable@freebsd.org; Thu, 13 Oct 2016 09:59:51 +0000 Subject: Re: ZFS l2arc broken in 10.3 To: freebsd-stable@freebsd.org References: From: Pete French Message-ID: <530d4222-535e-b29d-aba7-9520644dc6e5@ingresso.co.uk> Date: Thu, 13 Oct 2016 10:59:51 +0100 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit 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: Thu, 13 Oct 2016 09:59:53 -0000 Ok, thats a bit worry if true - but I can confirm that l2arc works fine under 10.3 on amd64, so what you say about cross-compling might be true. Am taking an inetrest in this as I have just dpeloyed a lot of machines which are going to be relying on l2arc working to get reasobale performance. -pete. On 10/12/16 21:18, Peter wrote: > Details: > After upgrading 2 machines from 9.3 to 10.3-STABLE, on one of them the > l2arc stays empty (capacity alloc = 0), although it is online and gets > accessed. It did work well on 9.3. > > I did the following tests: > * Create a zpool on a stick, with two volumes: one filesystem and one > cache. The cache stays with alloc=0. > Export it and move it into the other machine. The cache immediately > fills. > Move it back, the cache stays with alloc=0. > -> this rules out all zpool/zfs get/set options, as they should > walk with the pool. > * Boot the GENERIC kernel. l2arc stays with alloc=0. > -> this rules out all my nonstandard kernel options. > * Boot in single user mode. l2arc stays with alloc=0. > -> this rules out all /etc/* config files. > * Delete the zpool.cache and reimport pools. l2arc stays with alloc=0. > * Copy the /boot/loader.conf settings to the other machine. The l2arc > still works there. > > I could not think of any remaining place where this could come from, > except the kernel code itself. > From there, I found these counters nicely incrementing each second: > kstat.zfs.misc.arcstats.l2_write_buffer_list_iter: 50758 > kstat.zfs.misc.arcstats.l2_write_buffer_list_null_iter: 27121 > kstat.zfs.misc.arcstats.l2_write_buffer_bytes_scanned: 40589375488 > But also this counter incrementing: > kstat.zfs.misc.arcstats.l2_write_full: 14604 > > Then with some printf in the code I saw these values provided: > buf_sz = hdr->b_size; > align = (size_t)1 << dev->l2ad_vdev->vdev_ashift; > buf_a_sz = P2ROUNDUP(buf_sz, align); > if ((write_asize + buf_a_sz) > target_sz) { > full = B_TRUE; > mutex_exit(hash_lock); > ARCSTAT_BUMP(arcstat_l2_write_full); > break; > } > > buf_sz = 1536 > align = 512 > buf_a_sz = 18446744069414585856 > write_asize = 0 > target_sz = 16777216 > > where buf_a_sz is obviousely off by (2^64 - 2^32). > > Maybe this is an effect of crosscompiling i386 on amd64. But anyway, as > long as i386 is still supported, it should not happen. > > > Now, my real concern is: if this really obvious ... made it undetected > until 10.3, how many other missing typecasts are still in the code?? > > _______________________________________________ > freebsd-stable@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org"