From owner-freebsd-hackers Wed Dec 8 15:22:39 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by hub.freebsd.org (Postfix) with ESMTP id 5CC5A1527F for ; Wed, 8 Dec 1999 15:22:36 -0800 (PST) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.9.3/8.9.1) id PAA44403; Wed, 8 Dec 1999 15:22:33 -0800 (PST) (envelope-from dillon) Date: Wed, 8 Dec 1999 15:22:33 -0800 (PST) From: Matthew Dillon Message-Id: <199912082322.PAA44403@apollo.backplane.com> To: Jason Young Cc: Alfred Perlstein , freebsd-hackers@FreeBSD.ORG Subject: Re: Getting a new MAP_ flag into mmap() prior to 4.x freeze References: Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG : : :I think that you imply explicit msync() calls still flush data to disk. Is :that the case? : :Jason Young :accessUS Chief Network Engineer msync never guarenteed the flushing of data to disk, it simply guarentees synchronization with the buffer cache. FreeBSD, however, uses a coherent VM/buffer-cache. The FreeBSD msync with the MS_SYNC flag appears to flush VM data to physical media, though in my test it is terribly slow (it doesn't cluster!). msync doesn't care whether the pages are NOSYNC or not. i.e. NOSYNC has no effect on the operation of msync(). msync() with the MS_ASYNC flag appears to cluster properly. -Matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message