Re: [PATCH 2/2] Futex non-page-pinning fix

[Rusty Russell <rusty@rustcorp.com.au>]

In message <Pine.LNX.4.44.0309020355160.1923-100000@localhost.localdomain> you 
write:
> On Mon, 1 Sep 2003, Hugh Dickins wrote:
> > 
> > 5. If you're not doing anything in __remove_from_page_cache (rightly
> > trying to avoid hotpath), you do need to futex_rehash in mm/swap_state.c
> > __delete_from_swap_cache (last time I did say without the __s, but that
> > would miss an instance you need to catch).  That will handle the swapoff
> > case amongst others.
> 
> Of course, the reason I originally said without the __s, was because
> move_from_swap_cache uses __delete_from_swap_cache, and we don't want
> interference there.  So best convert that to use __remove_from_page_cache
> instead, with INC_CACHE_INFO(del_total) outside the locking, after the
> set_page_dirty: would improve symmetry between move_from_ and move_to_.

But you previously said:

Message-ID: <Pine.LNX.4.44.0309012053110.1817-100000@localhost.localdomain>
> 2. Please leave mm/swap_state.c's move_to_swap_cache and move_from_swap_
> cache out of it.  I already explained how those are for tmpfs files, and
> it's only the file mapping and index you need to worry about, you won't
> see a such page while it's assigned to swapper_space.  If you're anxious
> to show that you've visited everywhere that modifies page->mapping, then
> add a comment or BUG, but not code which could mislead people into
> thinking futexes really need to be rehashed there.

Confused,
Rusty.
--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.