From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 25 Sep 1999 12:50:57 -0400 (EDT) From: James Simmons Subject: Re: mm->mmap_sem In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Andrea Arcangeli Cc: "Stephen C. Tweedie" , linux-mm@kvack.org List-ID: On Sat, 25 Sep 1999, Andrea Arcangeli wrote: > On Fri, 24 Sep 1999, James Simmons wrote: > > >Just out of curoisty how would one revoke all read-write to that page? > > man mprotect (have a look to PROT_NONE) > > >I know this would be expensive to do. > > If you don't know how to do that how do you know it's expensive? ;) Well I kind of figured I would have to do what mprotects does. I just needed someone to say yes mprotect is the way to not allow processes physical access to a memory region. I just wanted to make sure I was right. Also I don't want the process to be sent a SIGSEGV. I just want to put it to sleep for a period of time if it access such a region. > But indeed you are right: it's a bit expensive as if the pages are just > allocated you'll have to change all their ptes. Like mprotect does. How does this compare to unmmaping a large memory region and putting a process to sleep in a no_page_fault routine. Is their any way to do cooperative locking kernel side between two memory regions? If one is being access you can't physically access the other. I just want to process to sleep not kill it if it attempts this. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://humbolt.geo.uu.nl/Linux-MM/