[dm-devel] new dm-bufio
Mikulas Patocka
mpatocka at redhat.com
Tue Aug 23 14:16:03 UTC 2011
On Tue, 23 Aug 2011, Joe Thornber wrote:
> 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?
No, it would me much more complicated to export such numbers.
> 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).
I uploaded new version to
http://people.redhat.com/mpatocka/patches/kernel/dm-thinp-bufio/dm-bufio.patch
There is file "/sys/module/dm_bufio/parameters/peak_allocated" which
contains peak memory consumption. You can reset the value by writing 0 to
the file.
Mikulas
> - Joe
>
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