From owner-cvs-src@FreeBSD.ORG Sat Mar 27 12:28:06 2004 Return-Path: Delivered-To: cvs-src@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9893916A4CE; Sat, 27 Mar 2004 12:28:06 -0800 (PST) Received: from cs.rice.edu (cs.rice.edu [128.42.1.30]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8497943D1D; Sat, 27 Mar 2004 12:28:06 -0800 (PST) (envelope-from alc@cs.rice.edu) Received: from localhost (calypso.cs.rice.edu [128.42.1.127]) by cs.rice.edu (Postfix) with ESMTP id 3BD754AC83; Sat, 27 Mar 2004 14:28:06 -0600 (CST) Received: from cs.rice.edu ([128.42.1.30]) by localhost (calypso.cs.rice.edu [128.42.1.127]) (amavisd-new, port 10024) with LMTP id 08850-01-21; Sat, 27 Mar 2004 14:28:05 -0600 (CST) Received: by cs.rice.edu (Postfix, from userid 19572) id C415F4AC7F; Sat, 27 Mar 2004 14:28:05 -0600 (CST) Date: Sat, 27 Mar 2004 14:28:05 -0600 From: Alan Cox To: Mike Silbersack Message-ID: <20040327202805.GU19961@cs.rice.edu> References: <200403271950.i2RJoN9P033780@repoman.freebsd.org> <20040327140454.H3199@odysseus.silby.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040327140454.H3199@odysseus.silby.com> User-Agent: Mutt/1.3.28i X-Virus-Scanned: by amavis-20030616-p7 at cs.rice.edu cc: Alan Cox cc: cvs-src@FreeBSD.org cc: src-committers@FreeBSD.org cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern subr_param.c sys_pipe.c src/sys/sys pipe.h X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 27 Mar 2004 20:28:06 -0000 On Sat, Mar 27, 2004 at 02:05:56PM -0600, Mike Silbersack wrote: > > On Sat, 27 Mar 2004, Alan Cox wrote: > > > Log: > > Revise the direct or optimized case to use uiomove_fromphys() by the reader > > instead of ephemeral mappings using pmap_qenter() by the writer. The > > writer is still, however, responsible for wiring the pages, just not > > mapping them. Consequently, the allocation of KVA for the direct case is > > unnecessary. Remove it and the sysctls limiting it, i.e., > > kern.ipc.maxpipekvawired and kern.ipc.amountpipekvawired. The number > > of temporarily wired pages is still, however, limited by > > kern.ipc.maxpipekva. > > The best advantage of this change is that the workings of direct mapped > pipes make much more sense to those of us who are not VM experts. :) > I hope this also serves to motivate people to work on eliminating the buffer map. Consider uiomove_fromphys() as my contribution to that effort. :-) Alan