FreeBSD cache memory allocation
John Baldwin
jhb at freebsd.org
Wed Nov 14 12:38:09 PST 2007
On Wednesday 14 November 2007 11:11:41 am Rob Belics wrote:
> Someone I can't stand said this about FreeBSD. Though I know C, I don't
> know anything about this and would love to respond. My first thought was
> 'contigmalloc' but I'm not sure it's equivalent.
> [QUOTE]The kernel is really lacking some features. They need a method to
> set precise type of memory cache but BSD doesn't provide way to specify
> memory cache.
>
> For that reason MS has the beautiful
> MmAllocateContigousMemorySpecifyCache()[/QUOTE]
For kernel memory on i386 and amd64 in 6.3 and later you can use
pmap_change_attr() to adjust the caching mode of memory after you have
allocated it. It is best used only with allocations that are a multiple of
the page size.
--
John Baldwin
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