From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 11 Oct 1999 12:05:23 -0400 (EDT) From: Alexander Viro Subject: Re: locking question: do_mmap(), do_munmap() In-Reply-To: <14338.1859.507452.652164@dukat.scot.redhat.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: "Stephen C. Tweedie" Cc: Manfred Spraul , Andrea Arcangeli , linux-kernel@vger.rutgers.edu, Ingo Molnar , linux-mm@kvack.org List-ID: On Mon, 11 Oct 1999, Stephen C. Tweedie wrote: > Hi, > > On Sun, 10 Oct 1999 15:03:45 -0400 (EDT), Alexander Viro > said: > > > Hold on. In swap_out_mm() you have to protect find_vma() (OK, it doesn't > > block, but we'll have to take care of mm->mmap_cache) _and_ you'll have to > > protect vma from destruction all way down to try_to_swap_out(). And to > > vma->swapout(). Which can sleep, so spinlocks are out of question > > here. > > No, spinlocks would be ideal. The vma swapout codes _have_ to be > prepared for the vma to be destroyed as soon as we sleep. In fact, the > entire mm may disappear if the process happens to exit. Once we know > which page to write where, the swapout operation becomes a per-page > operation, not per-vma. Aha, so you propose to drop it in ->swapout(), right? (after get_file() in filemap_write_page()... Ouch. Probably we'ld better lambda-expand the call in filemap_swapout() - the thing is called from other places too)... -- 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/