>>>>> "Jason" == Jason B Akers <jason.b.akers@xxxxxxxxx> writes: Jason> The following series enables the use of Solid State hybrid drives Jason> ATA standard 3.2 defines the hybrid information feature, which Jason> provides a means for the host driver to provide hints to the Jason> SSHDs to guide what to place on the SSD/NAND portion and what to Jason> place on the magnetic media. I have been ripping my hair out in this department for a while. A colleague and I presented our findings at SNIA SDC a few weeks ago. I'm trying to find out if there's an embargo on the slides or if I can post them. First of all I completely agree with Dave's comments about hooking into fadvise()/madvise(). For my testing I also overloaded the existing priority fields but ended up deciding that it would be better to have a separate field (and cleaning up the priority high byte in bi_rw but that's part of a different patch set). My challenge with hints has been trying to bridge all the various existing approaches with the new stuff that's coming down the pipe in T10/T13 (LBMD hints) and NFS v4.2 ditto. That turned into a huge mapping table as well as a few amendments to what's currently being worked on in the standards bodies. I didn't actively pursue the hybrid drive hints because I didn't think there was much interest. But since there is we should combine our efforts. From an application and kernel perspective we need to have one type of hints that then get translated into whatever is suitable for NFS, T10, T13 or SATA-IO SSHDs. It looks like the SSHD hints are reasonably close to fadvise() which is great. I'll see if I can get a link to the slides out tomorrow. Otherwise I'll just redo them. -- Martin K. Petersen Oracle Linux Engineering -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
