![]() | ||||||||||
Messages in this thread |
>
>
>I'm curious about the last statement, is this to mean that a TLB entry will
>be reserved at set_fixmap() time in which the translation will happen, and
>that particular entry will be locked down for the duration of the mapping?
>
>
No. fixmap mappings are global - identical for all processes and all
cpus. Therefore it's not necessary to flush them during a task switch.
But that's just an optimization, not a mandatory feature:
On x86 it's possible to mark page table entries as global. Global
entries are not flushed by the normal tlb flush command, this gives a
slighly better performance. If your architecture doesn't support that,
then you can just flush everything during a task switch. I think the
support for global entries was added for the Pentium cpus - 80486 cpus
flush the whole tlb cache during a task switch.
--
Manfred
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
| |||||||||
| Last update: 2005-03-22 13:01 [from the cache] ©2003-2008 | ||||||||||