From owner-svn-src-all@FreeBSD.ORG Mon Dec 22 18:42:51 2014 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 6DB2E1E5; Mon, 22 Dec 2014 18:42:51 +0000 (UTC) Received: from mail-wi0-x235.google.com (mail-wi0-x235.google.com [IPv6:2a00:1450:400c:c05::235]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id F0B59171A; Mon, 22 Dec 2014 18:42:50 +0000 (UTC) Received: by mail-wi0-f181.google.com with SMTP id r20so8808965wiv.8; Mon, 22 Dec 2014 10:42:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=9KZr+71qCbBSryuzfKjk17uDVLYGqLr5gGHnwetAI6Q=; b=Yfr2fYqpegmOOUFneAIj8SEYtgMktiID29HiBV/idXbwA+wP28nIjWE/v8M0KN2hQi 2/cJWim2Xi1q4HXFLxtr7AaFjoYuKWW1/9HqqGl+xUxjZTIH8xGChgcdhBeN+YNj8TN5 szQWk5V0YCfojyeRciv2gfQf5In91tOQN5P+29Ah7SjP6SDu7cKyYwJGeGn+6iLvb4Ku k367KolmmOKez/+1kkCeqcgPVJduB/nj5fa4PXN5TQddLGrQUFU7hHLkBqz2QkuIJ6tB XuKaWNihvG0z9DpG7gGjHsgtHJLC+S8FMsHexkw9NvFn5w5qlDAi8wPPqQwRrzEdU63r Qe7g== MIME-Version: 1.0 X-Received: by 10.180.91.193 with SMTP id cg1mr34081966wib.26.1419273769374; Mon, 22 Dec 2014 10:42:49 -0800 (PST) Sender: adrian.chadd@gmail.com Received: by 10.216.106.195 with HTTP; Mon, 22 Dec 2014 10:42:49 -0800 (PST) In-Reply-To: <20141222172810.GY2148@kib.kiev.ua> References: <201412211332.sBLDW8VC030548@svn.freebsd.org> <20141221151425.GX2148@kib.kiev.ua> <5496F37D.5030903@FreeBSD.org> <201412220940.02509.jhb@freebsd.org> <20141222172810.GY2148@kib.kiev.ua> Date: Mon, 22 Dec 2014 10:42:49 -0800 X-Google-Sender-Auth: wIfifv2PFOAbysI5BxuYNAGmcHE Message-ID: Subject: Re: svn commit: r276008 - in head/sys: kern sys From: Adrian Chadd To: Konstantin Belousov Content-Type: text/plain; charset=UTF-8 Cc: "svn-src-head@freebsd.org" , "svn-src-all@freebsd.org" , "src-committers@freebsd.org" , Andriy Gapon , John Baldwin X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.18-1 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: Mon, 22 Dec 2014 18:42:51 -0000 On 22 December 2014 at 09:28, Konstantin Belousov wrote: > On Mon, Dec 22, 2014 at 09:40:02AM -0500, John Baldwin wrote: >> On Sunday, December 21, 2014 11:21:17 am Andriy Gapon wrote: >> > On 21/12/2014 17:14, Konstantin Belousov wrote: >> > > On Sun, Dec 21, 2014 at 04:45:28PM +0200, Andriy Gapon wrote: >> > >> On 21/12/2014 16:41, Konstantin Belousov wrote: >> > >>> Or, are you asking why caching of the name could be needed for >> > >>> core dump files at all ? >> > >> >> > >> Sort of. Why VN_OPEN_NAMECACHE is useful in the case of core dumps? >> > >> What does it make better? >> > > The vn_fullpath() mostly works for the core files after the change, >> > > comparing with the non-working state at all before. >> > > >> > >> > Ah, vn_fullpath(). Thank you. >> >> Is there something specific to core dumps that makes vn_fullpath() more >> useful to have working before a process tries to open the core? (As >> compared to other newly-created files) > > See other Rui' reply in the thread. It was done by his request. > > Basically, we cannot enable caching for CREATE, since operations like > extracting large archive, would flush the cache. Doing it rarely > and when needed is acceptable. The explained use case seems to > be warranted. .. 2c, sounds like having an ARC style replacement policy for namecache entries would be useful. (I mean the policy as described in the ARC paper, not the ZFS implementation as a block cache.) -adrian