Re: PATCH - raise max_anon limit

[Andrew Morton <akpm@osdl.org>]

Tim Hockin <thockin@sun.com> wrote:
>
> Attached is a patch to raise the limit of anonymous block devices.  The
>  sysctl allows the admin to set the order of pages allocated for the unnamed
>  bitmap from 1 page to the full MINORBITS limit.

It would be better to lose the sysctl and do it all dynamically.

Options are:

a) realloc the bitmap when it fills up

   Simple, a bit crufty, doesn't release memory.

b) lib/radix-tree.c

   Each entry in the radix tree can be a bitmap (radix-tree.c should
   have been defined to store unsigned longs, not void*'s.  Oh well), so
   you get good space utilisation, but finding a new entry will take ten or
   so lines of code.

c) lib/idr.c

   Worst space utilisation, but simplest code.


I'd go with c), personally.