RE: PATCH: allow percentile size of tmpfs (2.5.66 / 2.4.20-pre2)

[Hua Zhong]

There is at least one case that ramfs works but tmpfs doesn't.

If you have a loopback file A, and the following will fail in 2.4:

mount -t tmpfs tmpfs /mnt/tmp
extract file A to /mnt/tmp/A
mount -t ext2 -o loop /mnt/tmp /mnt/loopback

You'll get "ioctl: LOOP_SET_FD: Invalid argument".

But ramfs works great.

Is this a bug or feature?

> Uuh, now you are beating me with my old statements ;-)
>
> tmpfs has the drawback that the in memory data structures are bigger
> than ramfs'. But the core of tmpfs is always compiled in for anonymous
> shared memory. And it has size limits. So you are probably right, that
> tmpfs is the right choice.
>
> But you are arguing at a corner case. tmpfs is IMHO more often used on
> machines with swap and (at least for me) the use of swap as store for
> temporary data is the big point to use tmpfs. So the percentile should
> take swap into account.
>
> Greetings
> 		Christoph
>
>
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