From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265187AbUFBI4P (ORCPT ); Wed, 2 Jun 2004 04:56:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265206AbUFBI4P (ORCPT ); Wed, 2 Jun 2004 04:56:15 -0400 Received: from Spamfilter.post.RO ([80.86.96.12]:53962 "EHLO spamfilter.post.ro") by vger.kernel.org with ESMTP id S265187AbUFBI4O (ORCPT ); Wed, 2 Jun 2004 04:56:14 -0400 From: dahood@post.ro X-Priority: 3 MIME-Version: 1.0 Message-Id: <40BD9615.000002.22735@server.post.ro> Date: Wed, 2 Jun 2004 11:55:47 +0300 (EEST) Content-Type: Text/Plain Content-Transfer-Encoding: 7bit To: linux-kernel@vger.kernel.org Subject: Locking pages in memory Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, I'm trying to lock some pages from a mmaped user memory (say user_addr). (mmap on a file) For this I did the following (in a kernel module): 1. with get_user I fault every page into the memory, then I get the physical address of each page. 2. I put PG_reserved and do a get_page on each page. 3. After I finish using the memory, I truncate the file used for mmap to 0, and close the file descriptor(this is done in user space). 4. In kernel space, I do set_page_count to 1, for every page, clear PG_reserved, and do put_page. My problem is that in kernel 2.4, this works perfectly, while in 2.6, when I do put_page, I get an bad state on page, because page_mapped is not 0 (page->pte.direct != 0), which means that the page in take into account into rmap. But because the page is PG_reserved, I think it shoudn't be. Is there is something more that I should do in kernel 2.6 if I'm using reserved pages, more than in 2.4? In kernel 2.4, I know that is my responsability to set the page count to 1, when I'm sure that there is no one else using the pages, and put_page to kernel. I tried a workaround in 2.6, by setting page->pte.direct=0, before doing the final put_page. In this way, the put_page function is happy, but when I try do large allocation in user space program, I keep getting segmentation fault, so I think that the pte.direct hack is not ok. Thank you, Dan