From owner-svn-src-all@FreeBSD.ORG Wed May 20 17:28:52 2015 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 2D59C2B1; Wed, 20 May 2015 17:28:52 +0000 (UTC) Received: from lauren.room52.net (lauren.room52.net [210.50.193.198]) by mx1.freebsd.org (Postfix) with ESMTP id E7E131866; Wed, 20 May 2015 17:28:51 +0000 (UTC) Received: from lgwl-lstewart2.corp.netflix.com (c110-22-60-167.eburwd6.vic.optusnet.com.au [110.22.60.167]) by lauren.room52.net (Postfix) with ESMTPSA id 137467E820; Thu, 21 May 2015 03:28:41 +1000 (EST) Message-ID: <555CC40C.1070502@freebsd.org> Date: Thu, 21 May 2015 03:27:40 +1000 From: Lawrence Stewart User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Eric van Gyzen , Hiren Panchasara CC: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r283136 - head/sys/netinet References: <201505200108.t4K181No006311@svn.freebsd.org> <555C09D5.9090709@freebsd.org> <20150520042438.GA95600@strugglingcoder.info> <555C2ABC.60102@freebsd.org> <555C89F4.9080607@FreeBSD.org> In-Reply-To: <555C89F4.9080607@FreeBSD.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=2.4 required=5.0 tests=DNS_FROM_AHBL_RHSBL, UNPARSEABLE_RELAY autolearn=no version=3.3.2 X-Spam-Level: ** X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on lauren.room52.net X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 20 May 2015 17:28:52 -0000 On 05/20/15 23:19, Eric van Gyzen wrote: > On 05/20/2015 02:33, Lawrence Stewart wrote: >> On 05/20/15 14:24, Hiren Panchasara wrote: >>> On 05/20/15 at 02:13P, Lawrence Stewart wrote: >>>> Hi Hiren, >>>> >>>> On 05/20/15 11:08, Hiren Panchasara wrote: >>>>> Author: hiren Date: Wed May 20 01:08:01 2015 New Revision: >>>>> 283136 URL: https://svnweb.freebsd.org/changeset/base/283136 >>>>> >>>>> Log: Add a new sysctl net.inet.tcp.hostcache.purgenow=1 to >>>>> expire and purge all entries in hostcache immediately. >>>>> >>>>> In collaboration with: bz, rwatson MFC after: 1 week Relnotes: >>>>> yes Sponsored by: Limelight Networks >>>> >>>> Why introduce a new sysctl and not change the existing behaviour >>>> of net.inet.tcp.hostcache.purge? >>> >>> I thought it'd make more sense to keep the existing behavior as is >>> and provide new knob for the new behavior. >> >> Don't think so - why would deferring a purge to the next purge run be >> useful compared to purging immediately? I'd strongly suggest you adapt >> this change to the existing purge sysctl. I can't see why anyone would >> miss the old functionality. > > I am generally wary of a question such as "Why would anyone want...", because as soon as the code is released, someone answers it. > > That being said, I have always wanted Hiren's purgenow behavior, and I've always been annoyed by the lazy-purge behavior. I would suggest implementing Lawrence's suggestion, but NOT MFC'ing it, since that would be a disruptive change. > > Thanks for your work, Hiren. I see no reason not to MFC it - it's not a POLA violation for a stable branch. When the user requests a purge, it's surely equally as good (and I think anyone of right mind would argue better ;) to purge immediately than some number of seconds "n" in the future, where "n" is between 1 and the value of net.inet.tcp.hostcache.prune. Cheers, Lawrence