On (11/09/07 14:48), Christoph Lameter didst pronounce: > On Tue, 11 Sep 2007, Nick Piggin wrote: > > > But that's not my place to say, and I'm actually not arguing that high > > order pagecache does not have uses (especially as a practical, > > shorter-term solution which is unintrusive to filesystems). > > > > So no, I don't think I'm really going against the basics of what we agreed > > in Cambridge. But it sounds like it's still being billed as first-order > > support right off the bat here. > > Well its seems that we have different interpretations of what was agreed > on. My understanding was that the large blocksize patchset was okay > provided that I supply an acceptable mmap implementation and put a > warning in. > Warnings == #2 citizen in my mind with known potential failure cases. That was the point I thought. > > But even so, you can just hold an open fd in order to pin the dentry you > > want. My attack would go like this: get the page size and allocation group > > size for the machine, then get the number of dentries required to fill a > > slab. Then read in that many dentries and pin one of them. Repeat the > > process. Even if there is other activity on the system, it seems possible > > that such a thing will cause some headaches after not too long a time. > > Some sources of pinned memory are going to be better than others for > > this of course, so yeah maybe pagetables will be a bit easier (I don't know). > > Well even without slab targeted reclaim: Mel's antifrag will sort the > dentries into separate blocks of memory and so isolate the issue. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab - 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
