Re: [PATCH] mm: remove compressed copy from zram in-memory

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 9 Apr 2013 10:02:31 +0900 Minchan Kim <minchan@kernel.org> wrote:

> > Also, what's up with the SWP_BLKDEV test?  zram doesn't support
> > SWP_FILE?  Why on earth not?
> > 
> > Putting swap_slot_free_notify() into block_device_operations seems
> > rather wrong.  It precludes zram-over-swapfiles for all time and means
> > that other subsystems cannot get notifications for swap slot freeing
> > for swapfile-backed swap.
> 
> Zram is just pseudo-block device so anyone can format it with any FSes
> and swapon a file. In such case, he can't get a benefit from
> swap_slot_free_notify. But I think it's not a severe problem because
> there is no reason to use a file-swap on zram. If anyone want to use it,
> I'd like to know the reason. If it's reasonable, we have to rethink a
> wheel and it's another story, IMHO.

My point is that making the swap_slot_free_notify() callback a
blockdev-specific thing was restrictive.  What happens if someone wants
to use it for swapfile-backed swap?  This has nothing to do with zram.

--
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/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>