On 04/08/2014 02:47 PM, Dave Hansen wrote: > On 04/08/2014 11:23 AM, Nathan Fontenot wrote: >> On 04/08/2014 11:13 AM, Dave Hansen wrote: >>> On 04/08/2014 01:27 AM, Li Zhong wrote: >>>> If Dave and others don't have further objections, it seems this small >>>> userspace incompatibility could be accepted by most of us, and I don't >>>> need to make a version 2. >>> >>> Let me ask another question then. What are the units of >>> phys_index/end_phys_index? How do we expose those units to userspace? >>> >> >> The documentation for these files just states that the files contain >> the first and last section id of memory in the memory block for >> phys_index and end_phys_index respectively. >> >> I'm not sure the values have ever been units of anything, at least not >> that I remember. > > <sigh> > > There are two units. SECTION_SIZE, which is completely internal to the > kernel, and block_size_bytes which used to be the same as SECTION_SIZE, > but is not now. Which one of those two is phys_index/end_phys_index in, > and if it is in terms of SECTION_SIZE like this patch proposes, how do > we tell userspace how large SECTION_SIZE is? > > block_size_bytes is supposed to tell you how large the sections are. In > the case where we lumped a bunch of sections together, we also bumped up > block_size_bytes. That's why we currently divide the *ACTUAL* section > number in phys_index/end_phys_index by block_size_bytes. > > That document really needs to be updated to stop referring to sections > (at least in the descriptions of the user interface). We can not change > the units of phys_index/end_phys_index without also changing > block_size_bytes. >
Re-reading the documentation. You're correct, it needs help. -Nathan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
