malloc backed md/mfs filesystem swapped?

Colin Percival colin.percival at wadham.ox.ac.uk
Fri Feb 13 17:44:30 PST 2004


At 00:56 14/02/2004, Robert Watson wrote:
>If you
>have swap available, you pretty much always want to use swap-backing for
>memory disks -- if there's room in memory they will run as fast as
>malloc-backed, but you don't have to be as worried about the "Oh shoot,
>I'm out of room" case.

   Actually, there is one consideration: swap-backed memory disks have a
sector size equal to the machine page size.  This will result in some
inflation in memory usage, and can confuse program which expect a sector
size of 512 bytes (for example, dd, which I plan on fixing but I haven't
gotten around to yet).

Colin Percival




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