From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 12 Apr 2000 15:45:14 +0100 From: "Stephen C. Tweedie" Subject: Re: page->offset Message-ID: <20000412154514.G7570@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: ; from pnilesh@in.ibm.com on Wed, Apr 12, 2000 at 06:34:21PM +0530 Sender: owner-linux-mm@kvack.org Return-Path: To: pnilesh@in.ibm.com Cc: "Stephen C. Tweedie" , linux-mm@kvack.org List-ID: Hi, On Wed, Apr 12, 2000 at 06:34:21PM +0530, pnilesh@in.ibm.com wrote: > > If a file is opened and from an offset which is not page aligned say from > offset 10. > When we read this file into the memory page ,where the first byte will be > loaded into the memory ? > In 2.2 the first byte of the page will be the 10th byte of the file. > In 2.3 the first byte will be first byte in the file and 10th byte is the > 10th in the file. No. The cache will always be page aligned in both 2.2 and 2.3 for all user IO and for all mmap()ed files. The _only_ case where we allow non-aligned mappings is when the execve() syscall is executed on a QMAGIC binary, in which case 2.2 will allow the mapping and will page the binary in at unaligned offsets when page faults occur. --Stephen -- 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.eu.org/Linux-MM/