From owner-freebsd-hackers@freebsd.org Sun Nov 18 19:30:21 2018 Return-Path: Delivered-To: freebsd-hackers@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 79A44110C8A2 for ; Sun, 18 Nov 2018 19:30:21 +0000 (UTC) (envelope-from rwmaillists@googlemail.com) Received: from mail-wr1-x434.google.com (mail-wr1-x434.google.com [IPv6:2a00:1450:4864:20::434]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4EDCD6C35F for ; Sun, 18 Nov 2018 19:30:20 +0000 (UTC) (envelope-from rwmaillists@googlemail.com) Received: by mail-wr1-x434.google.com with SMTP id l9so16892756wrt.13 for ; Sun, 18 Nov 2018 11:30:20 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=M/nWWUXlQHa/Vl9v9Rf0QEZ1wFwjaYuNL/pSllXm5oI=; b=P3/FoHBIuyx61onKdTiEsK8jm0hMCIXGvhPr2cat7kpukoQ3HQY5DJsgfhNMGAc30U OTiQESur6Hd5fMqTiNOz+wO41D3veCTei4C6ZUSycoLzE3Zne3jt1msrPlXHUG71/b3B HydbPAKTVceVvUuf+snGMavooaXjMWwdr65JeVDLEue6tQHC6zfswC3cbap3E1y6qOJ7 qIVMGYWYtVmoseCx8v2yzw0uOLYjd+tTsO7lDu5NUwpZVOGOzqtLmL0JDw3jPUGV1EOt Ykioruj0T9BHSPF1p8awRUsmCW76uU/VbEdmS330iqYPUE0M+05Qf/4RL0F63TJM2xka z2OQ== X-Gm-Message-State: AA+aEWbqTv0/phr9y2P6Wz2U+aesu+tgiLGLc89cyoqWJ3YLHZ55sgBT yKfkLlp2+sa9POc++tFFu7205PNP X-Google-Smtp-Source: AFSGD/Udqn2sVYo+64wnDgqmo5elje6EHNbtQL4d3z440q6OTl3c2e/MR4vGt8xabPMR2k8sXNFQUQ== X-Received: by 2002:a5d:4b01:: with SMTP id v1mr9846684wrq.5.1542569418751; Sun, 18 Nov 2018 11:30:18 -0800 (PST) Received: from gumby.homeunix.com ([90.211.70.103]) by smtp.gmail.com with ESMTPSA id y83-v6sm26218869wmb.20.2018.11.18.11.30.17 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sun, 18 Nov 2018 11:30:18 -0800 (PST) Date: Sun, 18 Nov 2018 19:30:16 +0000 From: RW To: freebsd-hackers@freebsd.org Subject: Re: 13-CURRENT: several GB swap being used despite plenty of free RAM Message-ID: <20181118193016.094cca9d@gumby.homeunix.com> In-Reply-To: References: <201811180154.wAI1smhg049214@slippy.cwsent.com> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; amd64-portbld-freebsd11.1) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 4EDCD6C35F X-Spamd-Result: default: False [-3.63 / 15.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; R_DKIM_ALLOW(-0.20)[googlemail.com]; NEURAL_HAM_MEDIUM(-1.00)[-0.998,0]; FROM_HAS_DN(0.00)[]; R_SPF_ALLOW(-0.20)[+ip6:2a00:1450:4000::/36]; FREEMAIL_FROM(0.00)[googlemail.com]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-hackers@freebsd.org]; TO_DN_NONE(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; RCVD_COUNT_THREE(0.00)[3]; IP_SCORE(-0.72)[ipnet: 2a00:1450::/32(-1.78), asn: 15169(-1.73), country: US(-0.09)]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_TRACE(0.00)[googlemail.com:+]; DMARC_POLICY_ALLOW(-0.50)[googlemail.com,quarantine]; RCVD_IN_DNSWL_NONE(0.00)[4.3.4.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.0.0.4.6.8.4.0.5.4.1.0.0.a.2.list.dnswl.org : 127.0.5.0]; MX_GOOD(-0.01)[alt3.gmail-smtp-in.l.google.com,alt4.gmail-smtp-in.l.google.com,gmail-smtp-in.l.google.com,alt2.gmail-smtp-in.l.google.com,alt1.gmail-smtp-in.l.google.com]; NEURAL_HAM_SHORT(-0.90)[-0.900,0]; RECEIVED_SPAMHAUS_PBL(0.00)[103.70.211.90.zen.spamhaus.org : 127.0.0.10]; FROM_EQ_ENVFROM(0.00)[]; FREEMAIL_ENVFROM(0.00)[googlemail.com]; ASN(0.00)[asn:15169, ipnet:2a00:1450::/32, country:US]; RCVD_TLS_LAST(0.00)[] X-Rspamd-Server: mx1.freebsd.org X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 18 Nov 2018 19:30:21 -0000 On Sun, 18 Nov 2018 17:53:52 +0100 (CET) Wojciech Puchar wrote: > why someone changes WELL WORKING swapping algorithm? > > On Sun, 18 Nov 2018, Stefan Blachmann wrote: > > > So I guess the unwillingness of the developer team to add an option > > like "NoPreemptiveSwapping", which disables swapping out as long as > > there is free physical memory available, is of psychological > > nature. > > in FReeBSD 12 there is > > vm.swap_idle_threshold2: 10 > vm.swap_idle_threshold1: 2 > vm.swap_idle_enabled: 0 > > > which works as expected and can be turned on or off as required. The above settings are about process level swapping, i.e. the deactivation of whole processes, they don't control swapping in the sense of paging out to the swap device. By default process swapping is only used under extreme memory shortage, setting vm.swap_idle_enabled=1 allows idle processes to be deactivated. It's only really intended for some special cases like login servers, which tend to have a lot of inactive shell and editor processes. Changing those setting wont reduce swap usage, they may increase it.