Re: [PATCH -mm 05/15] free swap space on swap-in/activation

[Rik van Riel <riel@redhat.com>]

On Tue, 13 May 2008 22:00:44 +0900
Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:

> On 2008/05/12 22:33 +0900, Rik van Riel wrote:
> > On Mon, 12 May 2008 20:21:32 +0900
> > Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:
> > 
> >> So, the intention of this patch is
> >> not to free a swap space of swap cache that has already swapped in
> >> and only used one process as do_swap_page() does,
> >> but to free a swap space that is only used as a swap cache
> >> (not used by any processes), right?
> > 
> > No.  The code should also free the swap space of pages that are
> > mapped by processes, in order to free up swap space for other
> > uses.  This only happens if vm_swap_full() is true.
> > 
> 
> OK.
> 
> I thought that current code cannot free the swap space
> of pages that are mapped by processes(and I think it cannot),
> so I asked the intention of this patch for clarification.

You may be right, due to the refcounting magic that is going
on.  I will verify the code and send in a fix if it turns out
to be needed.

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