From: Andrew Morton <akpm@osdl.org>
To: Andrea Arcangeli <andrea@suse.de>
Cc: hugh@veritas.com, vrajesh@umich.edu,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [RFC][PATCH 1/3] radix priority search tree - objrmap complexity fix
Date: Thu, 1 Apr 2004 16:52:16 -0800 [thread overview]
Message-ID: <20040401165216.40b9be98.akpm@osdl.org> (raw)
In-Reply-To: <20040402001535.GG18585@dualathlon.random>
Andrea Arcangeli <andrea@suse.de> wrote:
>
> > @@ -149,8 +149,14 @@ int rw_swap_page_sync(int rw, swp_entry_
> > };
> >
> > lock_page(page);
> > -
> > + /*
> > + * This library call can be only used to do I/O
> > + * on _private_ pages just allocated with alloc_pages().
> > + */
> > BUG_ON(page->mapping);
> > + BUG_ON(PageSwapCache(page));
> > + BUG_ON(PageAnon(page));
> > + BUG_ON(PageLRU(page));
> > ret = add_to_page_cache(page, &swapper_space, entry.val, GFP_KERNEL);
> > if (unlikely(ret)) {
> > unlock_page(page);
>
>
> the good thing is that I believe this fix will make it work with the -mm
> writeback changes. However this fix now collides with anon-vma since
> swapsuspend passes compound pages to rw_swap_page_sync and
> add_to_page_cache overwrites page->private and the kernel crashes at the
> next page_cache_get() since page->private is now the swap entry and not
> a page_t pointer.
Why do swapcache pages have their ->index in ->private? That should have
been commented.
(hugetlb pages are also added to pagecache, and they are compound, but the
code looks OK).
> So I guess I've a good reason now to giveup trying to
> add the page to the swapcache, and to just fake the radix tree like I
> did in my original fix. That way the page won't be swapcache either so I
> don't even need to use get_page to avoid remove_exclusive_swap_page to
> mess with it.
The BUG_ON in radix_tree_tag_set() is a fairly arbitrary sanity check:
"hey, why are you tagging a non-existent item?".
We could simply replace it with a `return NULL;'?
next prev parent reply other threads:[~2004-04-02 0:50 UTC|newest]
Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <Pine.LNX.4.44.0403150527400.28579-100000@localhost.localdomain>
2004-03-21 22:10 ` [RFC][PATCH 1/3] radix priority search tree - objrmap complexity fix Rajesh Venkatasubramanian
2004-03-21 22:12 ` [RFC][PATCH 2/3] Dave & Hugh's objrmap patch Rajesh Venkatasubramanian
2004-03-21 22:13 ` [RFC][PATCH 3/3] Covert objrmap to use prio_tree Rajesh Venkatasubramanian
2004-03-21 22:26 ` URL typo Rajesh Venkatasubramanian
2004-03-22 0:46 ` [RFC][PATCH 1/3] radix priority search tree - objrmap complexity fix Andrea Arcangeli
2004-03-22 2:32 ` Rik van Riel
2004-03-22 3:49 ` Rajesh Venkatasubramanian
2004-03-22 4:02 ` Rik van Riel
2004-03-22 4:21 ` put_super for proc Abhishek Rai
2004-03-22 12:04 ` Maneesh Soni
2004-03-25 22:59 ` [RFC][PATCH 1/3] radix priority search tree - objrmap complexity fix Andrea Arcangeli
2004-03-26 4:06 ` Rajesh Venkatasubramanian
2004-03-26 7:53 ` Andrea Arcangeli
2004-03-26 15:43 ` Rajesh Venkatasubramanian
2004-03-26 17:58 ` Andrea Arcangeli
2004-03-27 19:51 ` Rajesh Venkatasubramanian
2004-03-29 17:22 ` Andrea Arcangeli
2004-03-29 17:50 ` Rajesh Venkatasubramanian
2004-03-29 18:01 ` Andrea Arcangeli
2004-03-29 20:40 ` Andrew Morton
2004-03-29 22:24 ` Hugh Dickins
2004-03-29 22:54 ` Andrea Arcangeli
2004-03-29 23:08 ` William Lee Irwin III
2004-03-29 22:39 ` Andrea Arcangeli
2004-03-29 22:42 ` Andrew Morton
2004-03-31 15:07 ` Andrea Arcangeli
2004-03-31 15:26 ` Andrea Arcangeli
2004-03-31 16:45 ` Hugh Dickins
2004-03-31 17:28 ` Andrea Arcangeli
2004-04-01 0:45 ` Andrea Arcangeli
2004-04-01 1:22 ` Andrew Morton
2004-04-01 1:26 ` Andrea Arcangeli
2004-04-01 1:51 ` Andrew Morton
2004-04-01 2:01 ` Andrea Arcangeli
2004-04-01 5:05 ` Hugh Dickins
2004-04-01 13:35 ` Andrea Arcangeli
2004-04-01 15:09 ` Andrea Arcangeli
2004-04-01 15:15 ` Andrea Arcangeli
2004-04-02 0:15 ` Andrea Arcangeli
2004-04-02 0:52 ` Andrew Morton [this message]
2004-04-02 1:06 ` Andrea Arcangeli
2004-04-02 1:03 ` Hugh Dickins
2004-04-02 1:16 ` Andrea Arcangeli
2004-04-02 1:36 ` Andrew Morton
2004-04-02 2:00 ` Andrea Arcangeli
2004-04-02 2:08 ` Andrew Morton
2004-04-02 2:22 ` Andrea Arcangeli
2004-04-02 6:05 ` Christoph Hellwig
2004-04-02 7:07 ` Paul Mackerras
2004-04-02 7:11 ` Christoph Hellwig
2004-04-02 15:28 ` Andrea Arcangeli
2004-04-02 15:22 ` Andrea Arcangeli
2004-04-02 15:27 ` Christoph Hellwig
2004-04-02 15:38 ` Andrea Arcangeli
2004-04-02 15:45 ` Andrea Arcangeli
2004-04-02 9:43 ` Christoph Hellwig
2004-04-02 10:21 ` Marc-Christian Petersen
2004-04-02 10:55 ` Hugh Dickins
2004-04-02 16:46 ` Andrea Arcangeli
2004-04-02 18:59 ` Christoph Hellwig
2004-04-02 19:29 ` Andrea Arcangeli
2004-04-02 19:54 ` Christoph Hellwig
2004-04-02 20:35 ` Andrea Arcangeli
2004-04-03 8:40 ` Christoph Hellwig
2004-04-03 15:20 ` Andrea Arcangeli
2004-04-03 15:59 ` Andrea Arcangeli
2004-04-03 17:02 ` Andrea Arcangeli
2004-04-05 9:59 ` Christoph Hellwig
2004-04-05 12:11 ` Christoph Hellwig
2004-04-05 16:08 ` Andrea Arcangeli
2004-04-06 4:22 ` Andrea Arcangeli
2004-04-06 4:43 ` Andrew Morton
2004-04-06 5:14 ` Christoph Hellwig
2004-04-06 21:54 ` Andrea Arcangeli
2004-04-07 1:39 ` Nathan Scott
2004-04-06 5:16 ` Christoph Hellwig
2004-04-06 16:01 ` Andrea Arcangeli
2004-04-07 1:33 ` Nathan Scott
2004-04-03 17:40 ` Andrea Arcangeli
2004-04-03 20:02 ` Andrew Morton
2004-04-03 23:27 ` Andrea Arcangeli
2004-04-03 23:46 ` Andrew Morton
2004-04-04 0:40 ` Andrea Arcangeli
2004-04-08 19:10 ` Bill Davidsen
2004-04-20 22:29 ` Pavel Machek
2004-04-02 20:13 ` Pavel Machek
2004-04-02 21:42 ` Andrea Arcangeli
2004-04-02 21:45 ` Pavel Machek
2004-04-02 21:49 ` Andrea Arcangeli
2004-03-29 18:12 ` Hugh Dickins
2004-03-29 18:20 ` Andrea Arcangeli
2004-03-29 18:38 ` Christoph Hellwig
2004-03-29 21:30 ` 2.6.5-rc2-aa5 Rajesh Venkatasubramanian
2004-03-29 22:50 ` 2.6.5-rc2-aa5 Andrea Arcangeli
2004-04-05 3:14 ` [RFC][PATCH 1/3] radix priority search tree - objrmap complexity fix Rajesh Venkatasubramanian
2004-04-05 4:42 ` Andrea Arcangeli
2004-03-26 12:26 ` William Lee Irwin III
2004-03-26 19:18 ` Andrea Arcangeli
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