On Tue, Jul 01, 2014 at 07:39:15PM +0100, Mel Gorman wrote: > The fair zone policy itself is partially working against the lowmem > reserve idea. The point of the lowmem reserve was to preserve the lower > zones when an upper zone can be used and the fair zone policy breaks > that. The fair zone policy ignores that and it was never reconciled. The > dirty page distribution does a different interleaving again and was never > reconciled with the fair zone policy or lowmem reserves. kswapd itself was > not using the classzone_idx it actually woken for although in this case > it may not matter. The end result is that the model is fairly inconsistent > which makes comparison against it a difficult exercise at best. About all > that was left was that from a performance perspective that the fair zone > allocation policy is not doing the right thing for streaming workloads. > The inevitable feedback will be to reconcile those differences so I'm redid the series and queued it for testing. Patch list currently looks like mm: pagemap: Avoid unnecessary overhead when tracepoints are deactivated mm: Rearrange zone fields into read-only, page alloc, statistics and page reclaim lines mm: page_alloc: Add ALLOC_DIRTY for dirty page distribution mm: page_alloc: Only apply the fair zone allocation policy if it's eligible mm: page_alloc: Only apply either the fair zone or dirty page distribution policy, not both mm: page_alloc: Reduce cost of the fair zone allocation policy mm: page_alloc: Reconcile lowmem reserves with fair zone allocation policy mm: vmscan: Fix oddities with classzone and zone balancing mm: vmscan: Reconcile balance gap lowmem reclaim with fair zone allocation policy mm: vmscan: Remove classzone considerations from kswapd decisions About 13 hours to test for ext3 on the small machine, 3 days for the larger machine. The test could be accelerated by either reducing the iterations or the memory size of the machine but that would distort the results too badly. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>