From owner-svn-src-all@FreeBSD.ORG Wed Mar 13 15:18:46 2013 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 103E0E99; Wed, 13 Mar 2013 15:18:46 +0000 (UTC) (envelope-from glebius@FreeBSD.org) Received: from cell.glebius.int.ru (glebius.int.ru [81.19.69.10]) by mx1.freebsd.org (Postfix) with ESMTP id 67B87DBD; Wed, 13 Mar 2013 15:18:44 +0000 (UTC) Received: from cell.glebius.int.ru (localhost [127.0.0.1]) by cell.glebius.int.ru (8.14.6/8.14.6) with ESMTP id r2DFIhMw070964; Wed, 13 Mar 2013 19:18:43 +0400 (MSK) (envelope-from glebius@FreeBSD.org) Received: (from glebius@localhost) by cell.glebius.int.ru (8.14.6/8.14.6/Submit) id r2DFIhbN070963; Wed, 13 Mar 2013 19:18:43 +0400 (MSK) (envelope-from glebius@FreeBSD.org) X-Authentication-Warning: cell.glebius.int.ru: glebius set sender to glebius@FreeBSD.org using -f Date: Wed, 13 Mar 2013 19:18:43 +0400 From: Gleb Smirnoff To: Andre Oppermann Subject: Re: svn commit: r248196 - head/sys/nfs Message-ID: <20130313151843.GS48089@FreeBSD.org> References: <201303121219.r2CCJN5Z069789@svn.freebsd.org> <513F3A54.3090702@freebsd.org> <20130312150053.GI48089@FreeBSD.org> <513F4A39.8040107@freebsd.org> <20130312155005.GJ48089@FreeBSD.org> <513F58C0.4050302@freebsd.org> <20130312194936.GL48089@FreeBSD.org> <513F9BC9.3060300@freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=koi8-r Content-Disposition: inline In-Reply-To: <513F9BC9.3060300@freebsd.org> User-Agent: Mutt/1.5.21 (2010-09-15) Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.14 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, 13 Mar 2013 15:18:46 -0000 Okay, I will redo my patch to make default not to allow > PAGE_SIZE clusters. On Tue, Mar 12, 2013 at 10:19:05PM +0100, Andre Oppermann wrote: A> Jumbos always were physically contiguous. That was the very reason for A> their existence. They were invented to allow early NIC's with limited A> DMA capabilities to handle jumbo ethernet frames. Today they should only A> be used for DMA challenged NIC's and nothing else. They definitely were not physically contigous prior to r174247. A> > Let me repeat: there is a lot of code, that does handmade allocation of A> > an mbuf chain of an arbitrary length using mbufs and common clusters. This A> > code can be cut and use m_getm2(), if we can restrict it to avoid page size A> > clusters. I don't have time to dig deeper in the code and analyze and test A> > whether it can support page sized clusters in chains. A> A> m_getm2() can be used in any such case and doesn't have to avoid PAGE_SIZE A> clusters. PAGE_SIZE jumbo clusters are fine. Larger than PAGE_SIZE is not. A> A> When the code is able to work with mbuf chains the exact size of each cluster A> isn't important anymore. We can use the optimal size. Do you volunteer to fix if anything is broken? If not, I'd prefer to be conservative and make m_getm() capable to produce chains without clusters bigger than MCLBYTES. -- Totus tuus, Glebius.