[linux-mm-cc] Compcache as Ramdisk

[Nitin Gupta]

On 07/10/2009 10:21 AM, John McCabe-Dansted wrote:
> On Fri, Jul 10, 2009 at 12:38 PM, Vijayendra Suman 
> <vijayendra.suman at gmail.com <mailto:vijayendra.suman at gmail.com>> wrote:
>
>     Hi,
>
>     I want to use compcache 0.3 release as ramfs, which could be used
>     for processes for shred memory communication.
>     Currently, I compcache acts as virtual block driver and act as
>     swap Filesystem
>
>     1) swapoff compcache partition
>     2) mkfs.vfat -F 32 -S 4096 /dev/ramzswap0
>     3) mount /dev/ramzswap0 /mnt 
>
>
> ramzswap is not a generic block device, so as I understand you cannot 
> mount normal filesystems on it (It only supports I/O of size PAGE_SIZE).
>
> Would something like the following suffice?
>
> 1) swapon /dev/ramzswap
> 2) mount -t tmpfs -o size=1G,nr_inodes=10k,mode=0700 tmpfs /space
>
> http://en.wikipedia.org/wiki/TMPFS
>
> The linux kernel should swap out tmpfs pages that have not been 
> frequently used, so this should be fairly close to what you want. 
> tmpfs is probably a better fit for this than vfat anyway.

tmpfs solution looks good since ramzswap is not a generic block device.

BTW, Vijayendra, why do you want to stick with version 0.3 which is more 
than a year old?
This version uses 'TLSF' allocator which has problem of exhausting 
vmalloc area pretty quickly. Did you get any problems with compcache-0.5.3?


Nitin