Re: new dm-bufio

[Joe Thornber <thornber@redhat.com>]

On Mon, Aug 22, 2011 at 04:05:28PM -0400, Mikulas Patocka wrote:
> I uploaded new dm-bufio patch at 
> http://people.redhat.com/mpatocka/patches/kernel/dm-thinp-bufio/dm-bufio.patch
> 
> It reports the number of allocated bytes in 
> "/sys/module/dm_bufio/parameters/". There is a file "total_allocated" that 
> contains the number of bytes allocated for buffer cache. There are files 
> "allocated_get_free_pages", "allocated_kmalloc", "allocated_vmalloc" that 
> contain a number of allocated bytes with each method.
> 
> BTW. if you store "1" in "cache_size", it switches to a mode where it 
> won't allocate any memory during operation, relying only on preallocated 
> reserves --- useful for testing reservation deadlocks.

Great stuff, will merge straight away.

Are these stats broken down by bufio client?  ie. can we tell which pool/thinps are consuming all the space?

Would it be possible to record a high watermark as well?  This would
be very useful for benchmarking.  eg, we'd run a heavy load, then be
able to get the peak memory usage.  (Resetting this hwm would also be useful).

- Joe