From owner-svn-src-projects@FreeBSD.ORG Fri May 11 15:48:13 2012 Return-Path: Delivered-To: svn-src-projects@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id F04291065672; Fri, 11 May 2012 15:48:13 +0000 (UTC) (envelope-from mjg@semihalf.com) Received: from smtp.semihalf.com (smtp.semihalf.com [213.17.239.109]) by mx1.freebsd.org (Postfix) with ESMTP id 9479C8FC16; Fri, 11 May 2012 15:48:13 +0000 (UTC) Received: from localhost (unknown [213.17.239.109]) by smtp.semihalf.com (Postfix) with ESMTP id 01B4EC3CB7; Fri, 11 May 2012 17:48:03 +0200 (CEST) X-Virus-Scanned: by amavisd-new at semihalf.com Received: from smtp.semihalf.com ([213.17.239.109]) by localhost (smtp.semihalf.com [213.17.239.109]) (amavisd-new, port 10024) with ESMTP id G6yZ0F730E+J; Fri, 11 May 2012 17:48:02 +0200 (CEST) Received: from pcbsd-2342.semihalf.com (cardhu.semihalf.com [213.17.239.108]) by smtp.semihalf.com (Postfix) with ESMTPSA id 2D9A2C3840; Fri, 11 May 2012 17:48:02 +0200 (CEST) Date: Fri, 11 May 2012 17:48:10 +0200 From: Mateusz Guzik To: Konstantin Belousov Message-ID: <20120511154810.GA99005@pcbsd-2342.semihalf.com> References: <20120317085116.GC1340@garage.freebsd.pl> <20120317161050.GI75778@deviant.kiev.zoral.com.ua> <4FA8FFB9.7090002@freebsd.org> <20120508095631.GV2358@deviant.kiev.zoral.com.ua> <4FA94609.3060306@freebsd.org> <20120510103105.GG2358@deviant.kiev.zoral.com.ua> <4FABC64F.3060502@freebsd.org> <20120510115857.GH2358@deviant.kiev.zoral.com.ua> <20120510164519.GA13258@pcbsd-2342.semihalf.com> <20120511104648.GM2358@deviant.kiev.zoral.com.ua> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20120511104648.GM2358@deviant.kiev.zoral.com.ua> User-Agent: Mutt/1.5.21 (2010-09-15) Cc: svn-src-projects@freebsd.org, Grzegorz Bernacki , src-committers@freebsd.org Subject: Re: svn commit: r233072 - projects/nand/sys/kern X-BeenThere: svn-src-projects@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the src " projects" tree" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 11 May 2012 15:48:14 -0000 On Fri, May 11, 2012 at 01:46:48PM +0300, Konstantin Belousov wrote: > On Thu, May 10, 2012 at 06:45:19PM +0200, Mateusz Guzik wrote: > > http://people.freebsd.org/~raj/patches/misc/vfs_highdirtybuf.diff > > > > callbacks are expected to increase flushed counter if they happend to > > flush some buffers. > I do not think this is right. You need to call a routine when getnewblk() > is unable to find a buffer to recycle. > > As I understand, in your situation with lot of managed buffers, the dirty > queue could be just empty. I don't think I follow. Is your concern that with a lot of managed buffers and empty dirty queue nothing can be recycled? Or that managed buffers affect calls to buf_do_flush? I presume you talk about the code below the following: /* * If we exhausted our list, sleep as appropriate. We may have to * wakeup various daemons and write out some dirty buffers. * * Generally we are sleeping due to insufficient buffer space. */ if (bp == NULL) { Conditions that cause bufdaemon weakups/buf_do_flush calls seem to be not dependent on buffers being managed or not. buf_do_flush with our change always calls registered callbacks and the callback that we register calls code that knowns what nandfs managed buffers are dirty and flushes those. Buffers from dirty queues (if any) are flushed separately. If I'm wrong or misunderstood you, please elaborate on problem you have in mind. > > > > Example proof-of-concept (will be cleaned up) change for nandfs: > > http://people.freebsd.org/~raj/patches/misc/nandfs_vfs_highdirtybuf.diff > > > > Does this look reasonable? > > -- Mateusz Guzik