site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com On Jan 31, 2006, at 3:39 PM, Terry Lambert wrote: Since Herb was talking about using the memory for a large array, I recommended the API that I'd normally tell people to use for that usage. If this array was actually a driver DMA target, well, then one of the other options is probably a better bet. Regardless of whether the memory is likely to be a DMA target or not, allocating pageable kernel memory is probably the way to go. The sole exception to this case is when the memory is likely to be accessed on the paging path; typically anything in interrupt context or on the low-level I/O path. Or anything in a file-system. Or in a networking (when paging across NFS)... basically almost anything. On Feb 1, 2006, at 12:28 AM, Nikita Danilov wrote: Mike Smith writes: I'm not sure I agree with the NFS comment either. The real requirement is that you not deal with pageable memory while on the default-pager paging path. We rarely allocate swap files out on NFS. ;-) There used to be strong cross-chatter between paging out to the default pager and paging out dirty NFS (file) pages. Mostly this was because there was only one pageout thread (and if it got stuck in a page frame allocation while paging out NFS it couldn't be used to page out to the swap files). But there are now independent threads for paging internal (swap) and external (vnode) memory objects/files. Not that there aren't other reasons to allocate wired memory (latency requirements, etc...) - but I just wanted to clear this up. --Jim _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... This email sent to site_archiver@lists.apple.com