On Fri, 20 Apr 2007, Mel Gorman wrote: > I believe there is an assumption in parts of reclaim that LRU pages are > order-0. An interesting bug or two is likely to rear its head there.
Correct. We need to deal with reclaim etc. > > Note that this is proof-of-concept. Lots of functionality is missing and > > various issues have not been dealt with. Use of higher order pages may cause > > memory fragmentation. Mel Gorman's anti-fragmentation work is probably > > essential if we want to do this. We likely need actual defragmentation > > support. > > > > Ok, anti-fragmentation will help up to a point but it's awkward with ramfs > because those pages are not reclaimable or migratable no matter what the > order. Normal filesystems would fare much better fragmentation-wise. > > The problem is that the mapping gfp_mask is normally GFP_HIGH_MOVABLE but it's > GFP_HIGHUSER for ramfs. This patchset will increase the number of non-movable > high-order allocations quite considerably and it will tend to fragment memory > worse than we do currently. I can think of ways it can be dealt with > (even marking them RECLAIMABLE would help) so I'm not massively worried > now but I'll keep it in mind as things develop. Well I think we will have xfs support soon. Then we can deal with more issues and be more complete. What I wanted from this post was a consensus on how to proceed. There are many subsystems involved and I do not want to go off the deep end. - 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/
