From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3DF22784.7040502@embeddededge.com> Date: Sat, 07 Dec 2002 11:53:24 -0500 From: Dan Malek MIME-Version: 1.0 To: Joakim Tjernlund Cc: Paul Mackerras , Matt Porter , Pantelis Antoniou , linuxppc-embedded@lists.linuxppc.org Subject: Re: Regarding consistent_alloc References: <20021206085909.B17918@home.com> <15857.15826.513311.884408@argo.ozlabs.ibm.com> <003c01c29def$9b3d5df0$0300a8c0@jockeXP> Content-Type: text/plain; charset=us-ascii; format=flowed Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Joakim Tjernlund wrote: > Is consistent_alloc really needed? YES. > .... All uses I have seen in the kernel for the 8xx CPU can be solved with > a kmalloc.... The cpm_hostalloc() solves a different problem. It is used to allocate small non-cached object so you don't need the overhead of the cache management functions every time you want to do something like write a byte to a uart. It is specific to the CPM on the 8xx, so you can apply the proper assumptions about io mapping for a lightweight and efficient solution. I've constantly criticized the Linux VM implementation for having different functions and semantics for different VM spaces, and I'm always told something to the effect "...it's the Linux way to make it efficient..." So, I did the same thing for 8xx and CPM. There are lots of places in the Linux VM where you can apply only certain operations to certain VM objects. It seems I've kept up the spirit :-) -- Dan ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/