William Lee Irwin III <[EMAIL PROTECTED]> writes: > On Thu, 26 Apr 2007, Nick Piggin wrote: >>> OK, I would like to see them. And also discussions of things like why >>> we shouldn't increase PAGE_SIZE instead. > > On Thu, Apr 26, 2007 at 12:34:50AM -0700, Christoph Lameter wrote: >> Because 4k is a good page size that is bound to the binary format? Frankly >> there is no point in having my text files in large page sizes. However, >> when I read a dvd then I may want to transfer 64k chunks or when use my >> flash drive I may want to transfer 128k chunks. And yes if a scientific >> application needs to do data dump then it should be able to use very high >> page sizes (megabytes, gigabytes) to be able to continue its work while >> the huge dumps runs at full I/O speed ... > > It's possible to divorce PAGE_SIZE from the binary formats, though I > found it difficult to keep up with the update treadmill.
On x86_64 the sizes is actually 64K for executable binaries if I recall correctly. It certainly is not PAGE_SIZE, so we have some flexibility there. > Maybe it's > like hch says and I just needed to find more and better API cleanups. > I've only not tried to resurrect it because it's too much for me to do > on my own. I essentially collapsed under the weight of it and my 2.5.x > codebase ended up worse than Katrina as a disaster, which I don't want > to repeat and think collaborators or a different project lead from > myself are needed to avoid that happening again. But we still have some issues with mmap. But since we could increase PAGE_SIZE on x86_64 and not have to even worry about sub PAGE_SIZE mmaps. It is being suggested that if people really need larger physical pages that they just fix PAGE_SIZE. The everything just works. Thinking about it changing PAGE_SIZE on x86_64 should be about as hard as doing the 3-level vs 2-level page table format. We say we have a different page table format that uses a larger PAGE_SIZE. All arch code, all code in paths that we expect to change. Boom all done. It might be worth implementing just so people can play with different PAGE_SIZE values for benchmarking. I don't think the larger physical page size is really the issue here though. > It's unclear how much the situation has changed since 32-bit workload > feasibility issues have been relegated to ignorable or deliberate > "f**k 32-bit" status. The effect is doubtless to make it easier, though > to what degree I'm not sure. Perhaps. > Anyway, if that's being kicked around as an alternative, it could be > said that I have some insight into the issues surrounding it. Partially but also partially they are very much suggesting going down the same path. Currently mmap doesn't work with order >0 pages because they are not yet addressing these issues at all. This looks like a more flexible version of the old PAGE_CACHE_SIZE > PAGE_SIZE code. Which makes seriously question the whole idea. Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
