CACHE_LINE_SIZE too small, so struct vpglocks size alignment doesn't work

From: Svatopluk Kraus <onwahe_at_gmail.com>
Date: Fri, 1 Oct 2010 15:00:00 +0200
Hallo,

  a size of 'struct vpglocks' is padded to CACHE_LINE_SIZE size in
'sys/vm/vm_page.h'
header file. I work on a 'coldfire' port where CACHE_LINE_SIZE is 16 bytes and
sizeof(struct mtx) is 20 bytes thus size alignment doesn't work.

  I solved it somehow, but I like to learn how to solve it in spirit
of FreeBSD.
There are a couple of possibilities:

A1. Do nothing for small CACHE_LINE_SIZE.
A2. Pad to multiple of CACHE_LINE_SIZE.

B1. use #if with CACHE_LINE_SIZE
B2. use #if with __coldfire__

When I use B1 solution I need to known sizeof(struct mtx) value in
preprocessing time.
So, is it correct to use something like 'assym.s' magic
(sys/i386/i386/genassym.c)
in MI code? Or has someone another suggestion?

   Regards, Svata
Received on Fri Oct 01 2010 - 11:31:18 UTC

This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:40:07 UTC