From owner-freebsd-stable@freebsd.org Sat Feb 3 22:09:59 2018 Return-Path: Delivered-To: freebsd-stable@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 42DBBEF0BC6 for ; Sat, 3 Feb 2018 22:09:59 +0000 (UTC) (envelope-from marklmi26-fbsd@yahoo.com) Received: from sonic305-4.consmr.mail.bf2.yahoo.com (sonic305-4.consmr.mail.bf2.yahoo.com [74.6.133.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id E0E8E7D931 for ; Sat, 3 Feb 2018 22:09:58 +0000 (UTC) (envelope-from marklmi26-fbsd@yahoo.com) X-YMail-OSG: 6p.RC9MVM1mgRPWuT.49vRpoGLxxE.auwmlVTx9rE4BK0sUpkOBqTDSu81yoKCM HI0MGxgyUVYMFp3TcoRYjoDOwS3b.gFDBFgohHQV9c2Fx6UasNW1BIQ6eDVMH6NLIsjVIn8TrnPF Pxkb0G5bmt2fR8h9e2CrDagNpJylhGxLQR9EpZoIvmh6gu5FkcJEwccvUlZkYwkR591CGFTzbrE4 vqJBETplXikIwJtojnYEScTbC1mtkg55xXhQjh1KwO6bSREou50Vh.80TKORnmLFh7zLvcaUWynD RrOCuWoTj8q99SZPaiILYsyX4S4PnAB8oACk0BOVNh.vN.9DerF_8L_bYil9LTI9p52t8H11vFor W_X.KOnUOUsniwI.Eh1MSdIe64_KU_brLp1obwtUy62RCSZGwnXWUVgLm8g9bzZ3l25oAkFeqt3T t8y99ZdctZ0lAtG8SokeKW_iC3A7UhZ1pgddxEf3DluSuCFWryj.34jGzcIWABy62eKPR Received: from sonic.gate.mail.ne1.yahoo.com by sonic305.consmr.mail.bf2.yahoo.com with HTTP; Sat, 3 Feb 2018 22:09:58 +0000 Received: from smtpgate102.mail.bf1.yahoo.com (EHLO [192.168.1.25]) ([72.30.28.113]) by smtp405.mail.bf1.yahoo.com (JAMES SMTP Server ) with ESMTPA ID 35e4c7477b0057b032515b55c84ba93b for ; Sat, 03 Feb 2018 22:09:54 +0000 (UTC) From: Mark Millard Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Mac OS X Mail 11.2 \(3445.5.20\)) Subject: Re: 50 percent swap used, but "ps auxww" output shows no processes swapped out Message-Id: <4AF9AE33-887E-43F3-8885-B8EF37185407@yahoo.com> Date: Sat, 3 Feb 2018 14:09:53 -0800 To: FreeBSD-STABLE Mailing List X-Mailer: Apple Mail (2.3445.5.20) X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 03 Feb 2018 22:09:59 -0000 Brandon Allbery allbery.b at gmail.com wrote on Sat Feb 3 21:18:53 UTC 2018 : > Swapping whole processes out is not really a thing any more. = Individual > pages are paged to/from memory; if a memory page has no backing file, = it > will be allocated a block in swap space as its backing storage. >=20 > (I'm not sure "W" status even means swap; I thought whole-process = swapping > wasn't even supported any more.) =46rom what I've seen on the lists there is a technical distinction made between "kernel stacks for the process no longer memory resident" (swapped out) and other pages for the process having paged to disk and not being resident. But many tools do not seem to present that point of view and still reflect an older view in the terminology used, including in documentation. One has to interpret what one is shown as I understand. As an example, top can show RES being zero despite the kernel stacks for the process not having been moved to disk. RES zero might not mean what one might expect about "swapped out". I do not know if a W after the first letter in state (STAT) for "ps auxww" track the kernel-stacks' resident-vs-not status for the process or not. (Matching your not sure status.) > On Sat, Feb 3, 2018 at 4:14 PM, Michael Voorhis wrote: >=20 > > Hi all, > > > > I've got an amd64 system running 11.1-STABLE r325027, with something > > like 20G of swap. "swapinfo" shows that half the swap is used. > > > > So of course I'm curious to know which processes have been swapped > > out. I'm not using any "tmpfs" filesystems; no ZFS, no huge amounts = of > > wired-down memory. The system's got 16 processors and 128G of RAM. = "ps > > auxww" output shows *no* processes that are swapped out (2nd = character > > in "STAT" field is "W"). Not a single one. The only process with a W = in > > the stat field at all is the "[intr]" kernel thread. > > > > What is using the swapspace The so-called swapspace is really the paging/swap-space with most of the use being paging typically. (As Brandon indicated.) Once a page is paged out, if the process sticks around but does not use or free the page, the page likely stays paged-out. (I'm guessing some at the intended results for default tuning --and that you probably are using default tuning.) So the in-use swapspace is likely from one or more existing processes that did page-outs earlier. (Expect my descriptions to be over simplified, but hopefully pointing in the right general direction.) > > Please educate me. > > =3D=3D=3D Mark Millard marklmi at yahoo.com ( markmi at dsl-only.net is going away in 2018-Feb, late)