From owner-freebsd-hackers Sat Mar 3 11:25:27 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from bingnet2.cc.binghamton.edu (bingnet2.cc.binghamton.edu [128.226.1.18]) by hub.freebsd.org (Postfix) with ESMTP id 2589F37B71D for ; Sat, 3 Mar 2001 10:28:11 -0800 (PST) (envelope-from zzhang@cs.binghamton.edu) Received: from onyx (onyx.cs.binghamton.edu [128.226.140.171]) by bingnet2.cc.binghamton.edu (8.11.2/8.11.2) with ESMTP id f23ISAJ26376 for ; Sat, 3 Mar 2001 13:28:10 -0500 (EST) Date: Sat, 3 Mar 2001 13:28:08 -0500 (EST) From: Zhiui Zhang X-Sender: zzhang@onyx To: freebsd-hackers@freebsd.org Subject: Linux kiobuf stuff... Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG While looking at Linux 2.4 code, I see the kiobuf stuff. They implement it because Linux 2.2 lacks raw device support. I am wondering whether FreeBSD has a similar mechanism already in place. My reasonings: (1) FreeBSD's buffer is variable sized while Linux's buffer is fixed sized. So in the case of FreeBSD, a buffer can easily be associated with many pages. The kiobuf in Linux seems to limit the max I/O to 64KB. (2) We have physical buffers, they can be used separately (like in physio() and swapping) or they can be built on top of regular buffers (like in clustering I/O). Thanks for any enlightment. -Zhihui To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message