On Mon, Jun 03, 2013 at 10:25:33AM +0200, Peter Zijlstra wrote: > On Thu, May 30, 2013 at 02:04:06PM -0400, Johannes Weiner wrote: > > Previously, page cache radix tree nodes were freed after reclaim > > emptied out their page pointers. But now reclaim stores shadow > > entries in their place, which are only reclaimed when the inodes > > themselves are reclaimed. This is problematic for bigger files that > > are still in use after they have a significant amount of their cache > > reclaimed, without any of those pages actually refaulting. The shadow > > entries will just sit there and waste memory. In the worst case, the > > shadow entries will accumulate until the machine runs out of memory. > > > > Can't we simply prune all refault entries that have a distance larger > than the memory size? Then we must assume that no refault entry means > its too old, which I think is a fair assumption. Two workloads bound to two nodes might not push pages through the LRUs at the same pace, so a distance might be bigger than memory due to the faster moving node, yet still be a hit in the slower moving one. We can't really know until we evaluate it on a per-zone basis. -- 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
