tree 7daf7b505723f5ed2767353dc3fe53b939c46d87
parent d04714580f12379fcf7a0f799e86c92b96dd4e1f
author Mikulas Patocka <mpatocka@redhat.com> 1306670589 +0100
committer Alasdair G Kergon <agk@redhat.com> 1306670589 +0100

dm io: use fixed initial mempool size

Replace the arbitrary calculation of an initial io struct mempool size
with a constant.

The code calculated the number of reserved structures based on the request
size and used a "magic" multiplication constant of 4.  This patch changes
it to reserve a fixed number - itself still chosen quite arbitrarily.
Further testing might show if there is a better number to choose.

Note that if there is no memory pressure, we can still allocate an
arbitrary number of "struct io" structures.  One structure is enough to
process the whole request.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>