Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 9 Sep 2002 17:59:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 9 Sep 2002 17:59:11 -0400 Received: from packet.digeo.com ([12.110.80.53]:43732 "EHLO packet.digeo.com") by vger.kernel.org with ESMTP id ; Mon, 9 Sep 2002 17:59:10 -0400 Message-ID: <3D7D1AB4.B465ABE8@digeo.com> Date: Mon, 09 Sep 2002 15:03:32 -0700 From: Andrew Morton X-Mailer: Mozilla 4.79 [en] (X11; U; Linux 2.5.32 i686) X-Accept-Language: en MIME-Version: 1.0 To: Daniel Phillips CC: Rik van Riel , trond.myklebust@fys.uio.no, Chuck Lever , Linux Kernel Mailing List Subject: Re: invalidate_inode_pages in 2.5.32/3 References:

<3D7A8718.E626D3C7@digeo.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 09 Sep 2002 22:03:48.0149 (UTC) FILETIME=[C5F17650:01C2584C] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2136 Lines: 55 Daniel Phillips wrote: > > > I'm very unkeen about using the inaccurate invalidate_inode_pages > > for anything which matters, really. And the consistency of pagecache > > data matters. > > > > NFS should be using something stronger. And that's basically > > vmtruncate() without the i_size manipulation. > > Yes, that looks good. Semantics are basically "and don't come back > until every damm page is gone" which is enforced by the requirement > that we hold the mapping->page_lock though one entire scan of the > truncated region. (Yes, I remember sweating this one out a year > or two ago so it doesn't eat 100% CPU on regular occasions.) > > So, specifically, we want: > > void invalidate_inode_pages(struct inode *inode) > { > truncate_inode_pages(mapping, 0); > } > > Is it any harder than that? Pretty much - need to leave i_size where it was. But there are apparently reasons why NFS cannot sleepingly lock pages in this particular context. > By the way, now that we're all happy with the radix tree, we might > as well just go traverse that instead of all the mapping->*_pages. > (Not that I'm seriously suggesting rocking the boat that way just > now, but it might yield some interesting de-crufting possibilities.) Oh absolutely. unsigned long radix_tree_gang_lookup(void **pointers, unsiged long starting_from_here, unsigned long this_many); could be used nicely in readahead, drop_behind, truncate, invalidate and invalidate2. But to use it in writeback (desirable) we would need additional metadata in radix_tree_node. One bit per page, which means "this page is dirty" or "this subtree has dirty pages". I keep saying this in the hope that someone will take pity and write it. > ... > Now, what is this invalidate_inode_pages2 seepage about? Called from > one place. Sheesh. heh. We still do have some O_DIRECT/pagecache coherency problems. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/