On Wed, Apr 02, 2014 at 03:33:11PM -0700, Zach Brown wrote: > > One thing I'm not sure about: What's the largest IO (in terms of # of blocks, > > not # of struct iovecs) that I can throw at the kernel? > > Yeah, dunno. I'd guess big :). I'd hope that the PI code already has a > way to clamp the size of bios if there's a limit to the size of PI data > that can be managed downstream? I guess if we restricted the size of the PI buffer to a page's worth of pointers to struct page, that limits us to 128M on x64 with DIF and 512b sectors. That's not really a whole lot; I suppose one could (ab)use vmalloc. Yes, blk-integrity clamps the size of the bio to fit the downstream device's maximum integrity sg size. See max_integrity_segments for details, or the mostly-undocumented sg_prot_tablesize sysfs attribute that reveals it. I don't know what a practical limit is; scsi_debug sets it to 65536. --D > > - z > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
