From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3C830598.E2FB5E1A@zip.com.au> Date: Sun, 03 Mar 2002 21:26:48 -0800 From: Andrew Morton MIME-Version: 1.0 Subject: Re: [PATCH] radix-tree pagecache for 2.4.19-pre2-ac2 References: <20020303210346.A8329@caldera.de> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Hellwig Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: Christoph Hellwig wrote: > > I have uploaded an updated version of the radix-tree pagecache patch > against 2.4.19-pre2-ac2. News in this release: > > * fix a deadlock when vmtruncate takes i_shared_lock twice by introducing > a new mapping->page_lock that mutexes mapping->page_tree. (akpm) > * move setting of page->flags back out of move_to/from_swap_cache. (akpm) > * put back lost page state settings in shmem_unuse_inode. (akpm) > * get rid of remove_page_from_inode_queue - there was only one caller. (me) > * replace add_page_to_inode_queue with ___add_to_page_cache. (me) > > Please give it some serious beating while I try to get 2.5 working and > port the patch over 8) One of my reasons for absorbing ratcache into my current stuff is just that - to give it a serious beating. The fact that I found a hitherto-undiscovered BUG() and a deadlock in the first 30 minutes just shows what a mean beat I have :) I haven't yet even looked at lib/rat.c, but based on testing, I believe radix-tree pagecache is ready for 2.5. It would be good if the other Christoph could check over the shmem.c changes. As far as I know, the sole remaining "issue" is that block_flushpage() is being called under spinlock. Well, there's nothing new here. The kernel is *already* calling block_flushpage() under spinlock it at least three places. But it just so happens that there are never (?) any locked buffers against the page from those call sites. So I don't see the block_flushpage() thing as a blocker for this patch - it's just general ickiness which needs sorting out separately. I looked at block_flushpage() a month or so back. I ended up concluding that we should just create block_flushpage_atomic() and make it go BUG() if the page has locked buffers. Then call the atomic version from under spinlock, and leave it at that. - -- 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/