Date: Fri, 28 Feb 1997 17:08:18 -0600 (CST) From: Mark Tinguely <tinguely@plains.nodak.edu> To: terry@lambert.org Cc: dg@root.com, hackers@freebsd.org, jpt@msc.edu Subject: Re: Assumptions about kmem_malloc()... Message-ID: <199702282308.RAA25795@plains.nodak.edu>
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> The kernel is an virtual-to-physical address space map, isn't it? You > wouldn't need to introduce "handles" to do it, I think. I agree most kernel operations do not need wired contiguous physical memory, a virtual contiguous would suit most operations. I was thinking of the device drivers that require a physical contiguous address (or in the case of the IDT ATM card it requires several physical addresses of contiguous buffer addresses) programmed into it for long-term DMA. It seems to me, that with our new devices using host memory to save board costs, we need larger and larger chunks of contiguous physical memory because the DMA can't page fault a missing virtual page. > > It's not the kernel eating all the physical memory anyway. agreed, but as we allocate/release smaller chunks of physical unwired memory for DMA operations, can we keep the holes large enough for future allocations? --mark.
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