On Mon, Nov 26, 2007 at 11:38:14PM +0100, Thomas Bogendoerfer wrote: > I finally cleaned up Peter Fuerst's IP28 patches and solved some of > the IP28 issues in an IMHO more eye-friendly way (no ip26ucmem). > My IP28 boots with these patches from an Debian sarge NFS root and > is able to dd data from the harddrive. I'm going to send this patches > to this list and the subsystem maintainers. > > There is one change missing to get a working SCSI driver, because > a proper fix will be done in 2.6.25. The quick&dirty workaround is > below. The workaround makes sure that the sense_buffer lives in > its own cache line by aligning and extendin it. > > The patch "Use real cache invalidate" still contains one problem. > It will not flush the cache correctly, if the given size is bigger > than the second level cache. The problem is, that there is no index > invalidate cache operation available. I have two ideas to solve that. > One is to always do a range invalidate (maybe just by using this only > for R10k machines, which usually have quite big caches) or scan through > the cache and use the tag informations to do hit invalidate. If anybody > has a better idea please speak up :-) A while ago I instrumented the cacheflushing functions to get a histogram of cacheflush sizes. I was surprised to find no flushes larger than 64K even though I did that experiment on an Origin with a large RAID array copying huge amounts of data with reads and writes of several MB. So as long as that finding holds your code will work. Ralf
