From owner-freebsd-hackers Thu Nov 8 12: 5: 6 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.magmacom.com (mx1.magmacom.com [206.191.0.217]) by hub.freebsd.org (Postfix) with ESMTP id 0817437B419 for ; Thu, 8 Nov 2001 12:05:03 -0800 (PST) Received: from mail6.magma.ca (mail6 [206.191.0.248]) by mx1.magmacom.com (8.9.3/8.9.3) with ESMTP id PAA20830; Thu, 8 Nov 2001 15:05:02 -0500 (EST) Received: from lucan (mothership.macadamian.com [206.191.21.204]) by mail6.magma.ca (8.9.3/8.9.3) with SMTP id PAA28184; Thu, 8 Nov 2001 15:05:01 -0500 (EST) Message-ID: <02ae01c16891$4c1f4970$2a64a8c0@macadamian.com> From: "Jason Mawdsley" To: "mark tinguely" , Cc: References: <200111081947.fA8JlAe03457@web.cs.ndsu.nodak.edu> Subject: Re: mmap/madvise Date: Thu, 8 Nov 2001 15:09:39 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG > Jason Mawdsley asks: > > > > I am looking for a way to reserve memory, without actually allocating the > > > swap space. > > Alfred Perlstein answers: > > > Just proceed normally, freebsd does overcommit such that you really > > don't need to do anything special to get the results you desire. > > I assume Jason is writting a userland application, but I cannot tell > how he was using the allocated memory. Alfred is correct in that > allocated memory is not even physical until needed and only paged back > if modified AND space becomes low. > > Without information of what he was doing, I was trying to read between > the lines of his message and wonder if he needs the memory physically > there and wired (using mprotect) to prevent the memory from being released. I am creating a virtual memory manager. Currently I am doing a mmap(...PROT_NONE, MAP_ANON ) to reserve the memory. then when committing the memory I am using mprotect( ...PROT_READ | PROT_WRITE ) HTH Jason Mawdsley ~ jason@macadamian.com m_ a c a d a m i a n t e c h n o l o g i e s "Software developers for the world's leading technology companies." http://www.macadamian.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message