[parisc-linux] Progress - Update
Grant Grundler
grundler@cup.hp.com
Wed, 01 Dec 1999 10:55:21 -0800
"John David Anglin" wrote:
...
> Also, we may need to flush the cache line for &var. The coding in buffer.c
> which caused the original panic in xchg looks dubiousin this regoard:
>
> /* Update the reuse list */
> tail->b_next_free = xchg(&reuse_list, NULL);
> reuse_list = bh;
If this data struct is only touched by processors, they are coherent
and flushing is not needed. (Except VM aliases...but I have to ignore
this case due to my ignorance). If any driver DMAs this data and the
platform is I/O coherent (ie has ccio, epic or sba driver), processor
doesn't need to flush either. Processor should only need to flush on
*any* (SMP or not) platform which is not I/O coherent (assume the page
is mapped cacheable).
grant
Grant Grundler
Unix Developement Lab
+1.408.447.7253