From owner-freebsd-arm@freebsd.org Tue Feb 14 03:35:03 2017 Return-Path: Delivered-To: freebsd-arm@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 9BCBCCDCC8D for ; Tue, 14 Feb 2017 03:35:03 +0000 (UTC) (envelope-from markmi@dsl-only.net) Received: from asp.reflexion.net (outbound-mail-210-73.reflexion.net [208.70.210.73]) (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 4FDFF1FB1 for ; Tue, 14 Feb 2017 03:35:02 +0000 (UTC) (envelope-from markmi@dsl-only.net) Received: (qmail 11358 invoked from network); 14 Feb 2017 03:34:55 -0000 Received: from unknown (HELO rtc-sm-01.app.dca.reflexion.local) (10.81.150.1) by 0 (rfx-qmail) with SMTP; 14 Feb 2017 03:34:55 -0000 Received: by rtc-sm-01.app.dca.reflexion.local (Reflexion email security v8.30.0) with SMTP; Mon, 13 Feb 2017 22:34:55 -0500 (EST) Received: (qmail 21990 invoked from network); 14 Feb 2017 03:34:55 -0000 Received: from unknown (HELO iron2.pdx.net) (69.64.224.71) by 0 (rfx-qmail) with (AES256-SHA encrypted) SMTP; 14 Feb 2017 03:34:55 -0000 Received: from [192.168.1.111] (c-67-170-167-181.hsd1.or.comcast.net [67.170.167.181]) by iron2.pdx.net (Postfix) with ESMTPSA id 9A6CFEC7822; Mon, 13 Feb 2017 19:34:54 -0800 (PST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 10.2 \(3259\)) Subject: Re: Out of swap - NOT From: Mark Millard In-Reply-To: <20170214032036.GR2092@kib.kiev.ua> Date: Mon, 13 Feb 2017 19:34:53 -0800 Cc: wynkoop@wynn.com, freebsd-arm@freebsd.org Content-Transfer-Encoding: quoted-printable Message-Id: <75FA953B-4F23-4FF9-92D9-B78BA890EEA6@dsl-only.net> References: <20170211022800.14138f68@pearl> <20170214032036.GR2092@kib.kiev.ua> To: Konstantin Belousov X-Mailer: Apple Mail (2.3259) X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 14 Feb 2017 03:35:03 -0000 On 2017-Feb-13, at 7:20 PM, Konstantin Belousov = wrote: > On Mon, Feb 13, 2017 at 04:46:04PM -0500, Brett Wynkoop wrote: >> On Mon, 13 Feb 2017 15:55:11 -0500 >> Joe Nosay wrote: >>=20 >>> Is it possible to place the swap on a separate disk such as a usb? >>=20 >> Yes, but I am not sure what difference that will make. I would think = a >> swapfile is a swapfile. Yes I am swapping on a file because the = image >> autogrew the filesystem on first boot, so no chance to set up a >> partition. > swapfile write requires the write request to come through the = filesystem > write path, which might require the filesystem to allocate more memory > and read some data. E.g. it is known that any ZFS write request > allocates memory, and that write request on large UFS file might = require > allocating and reading an indirect block buffer to find the block = number > of the written block, if the indirect block was not yet read. >=20 > As result, swapfile swapping is more prone to the trivial and = unavoidable > deadlocks where the pagedaemon thread, which produces free memory, = needs > more free memory to make a progress. Swap write on the raw partition = over > simple partitioning scheme directly over HBA are usually safe, while = e.g. > zfs over geli over umass is the worst construction. Thanks for the explanation of bugzilla 206038: 11.0-CURRENT -r293227 (and others) arm (rpi2/BeagleBone Black) amd64 etc: swapfile usage hangs; swap partition works I'll copy your text into the comments for that submittal. =3D=3D=3D Mark Millard markmi at dsl-only.net