From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e5.ny.us.ibm.com (8.12.11/8.12.11) with ESMTP id k0EKjfsr024792 for ; Sat, 14 Jan 2006 15:45:41 -0500 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay02.pok.ibm.com (8.12.10/NCO/VERS6.8) with ESMTP id k0EKjcDQ121606 for ; Sat, 14 Jan 2006 15:45:41 -0500 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.12.11/8.13.3) with ESMTP id k0EKjbib024479 for ; Sat, 14 Jan 2006 15:45:37 -0500 Message-ID: <43C962F0.30400@us.ibm.com> Date: Sat, 14 Jan 2006 14:45:36 -0600 From: Brian Twichell MIME-Version: 1.0 Subject: Re: [PATCH/RFC] Shared page tables References: <43C7C4C7.8050409@cfl.rr.com> In-Reply-To: <43C7C4C7.8050409@cfl.rr.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Phillip Susi Cc: Dave McCracken , Hugh Dickins , Andrew Morton , Linux Kernel , Linux Memory Management List-ID: Phillip Susi wrote: > Shouldn't those kind of applications already be using threads to share > page tables rather than forking hundreds of processes that all mmap() > the same file? > We're talking about sharing anonymous memory here, not files. The feedback we've gotten on converting from a process-based to a thread-based model is that it's a major undertaking, when development and test expense is considered. It's understandable if one considers that they'd probably want to convert across on several operating systems at once to minimize the number of source trees they have to maintain. Also, the case for conversion isn't helped by the fact that at least two prominent commercial UNIX flavors either inherently share page tables, or provide an explicit memory allocation mechanism that achieves page table sharing (e.g. Intimate Shared Memory). Cheers, Brian -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org