From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 15 Mar 2006 11:00:31 -0800 (PST) From: Christoph Lameter Subject: Re: page migration: Fail with error if swap not setup In-Reply-To: <20060315213904.GA13771@dmt.cnet> Message-ID: References: <1142434053.5198.1.camel@localhost.localdomain> <20060315204742.GB12432@dmt.cnet> <20060315213904.GA13771@dmt.cnet> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Marcelo Tosatti Cc: Lee Schermerhorn , linux-mm@kvack.org, nickpiggin@yahoo.com.au, akpm@osdl.org List-ID: On Wed, 15 Mar 2006, Marcelo Tosatti wrote: > > That does not answer the question if VM_LOCKED pages should be > > migratable. We all agree that they should not show up on swap. > > I guess you missed the first part of the man page: > > All pages which contain a part of the specified memory range are > guaranteed be resident in RAM when the mlock system call returns > successfully and they are guaranteed to stay in RAM until the pages are > unlocked by munlock or munlockall, until the pages are unmapped via > munmap, or until the process terminates or starts another program with > exec. Child processes do not inherit page locks across a fork. > > That is, mlock() only guarantees that pages are kept in RAM and not > swapped. It does seem to refer to physical placing of pages. If VM_LOCKED is not pinning memory then how does one pin memory? There are likely applications / drivers that require memory not to move. Increase pagecount? -- 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