On 5/28/20 8:54 PM, Matthew Wilcox wrote:
On Thu, May 28, 2020 at 01:50:02PM -0400, Douglas Gilbert wrote:
On 2020-05-28 12:36 p.m., Hannes Reinecke wrote:
Use xarray for device lookup by target. LUNs below 256 are linear,
and can be used directly as the index into the xarray.
LUNs above 256 have a distinct LUN format, and are not necessarily
linear. They'll be stored in indices above 256 in the xarray, with
the next free index in the xarray.
I don't understand why you think this is an improvement over just
using an allocating XArray for all LUNs. It seems like more code,
and doesn't actually save you any storage space ... ?
The LUN range is 64 bit.
I was under the impression that xarray can only handle up to unsigned
long; which probably would work for 64bit systems, but there _are_ users
running on 32 bit, and they get patently unhappy when we have to tell
them 'sorry, not for you'.
At least I _know_ that I'll get complaints if I try a stunt like this.
If you can make xarray 64 bit on all systems, sure, I'm game.
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
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