From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH] recognize MAP_LOCKED in mmap() call Message-ID: From: Mark_H_Johnson@raytheon.com Date: Wed, 18 Sep 2002 14:18:05 -0500 MIME-Version: 1.0 Content-type: text/plain; charset=us-ascii Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, owner-linux-mm@kvack.org List-ID: Andrew Morton wrote: >(SuS really only anticipates that mmap needs to look at prior mlocks >in force against the address range. It also says > > Process memory locking does apply to shared memory regions, > >and we don't do that either. I think we should; can't see why SuS >requires this.) Let me make sure I read what you said correctly. Does this mean that Linux 2.4 (or 2.5) kernels do not lock shared memory regions if a process uses mlockall? If not, that is *really bad* for our real time applications. We don't want to take a page fault while running some 80hz task, just because some non-real time application tried to use what little physical memory we allow for the kernel and all other applications. I asked a related question about a week ago on linux-mm and didn't get a response. Basically, I was concerned that top did not show RSS == Size when mlockall(MCL_CURRENT|MCL_FUTURE) was called. Could this explain the difference or is there something else that I'm missing here? Thanks. --Mark H Johnson -- 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/