On Tue, Apr 25, 2017 at 08:56:57PM +0800, Huang, Ying wrote: > From: Huang Ying <[email protected]> > > To swap out THP (Transparent Huage Page), before splitting the THP, > the swap cluster will be allocated and the THP will be added into the > swap cache. But it is possible that the THP cannot be split, so that > we must delete the THP from the swap cache and free the swap cluster. > To avoid that, in this patch, whether the THP can be split is checked > firstly. The check can only be done racy, but it is good enough for > most cases. > > With the patch, the swap out throughput improves 3.6% (from about > 4.16GB/s to about 4.31GB/s) in the vm-scalability swap-w-seq test case > with 8 processes. The test is done on a Xeon E5 v3 system. The swap > device used is a RAM simulated PMEM (persistent memory) device. To > test the sequential swapping out, the test case creates 8 processes, > which sequentially allocate and write to the anonymous pages until the > RAM and part of the swap device is used up. > > Cc: Johannes Weiner <[email protected]> > Signed-off-by: "Huang, Ying" <[email protected]> > Acked-by: Kirill A. Shutemov <[email protected]> [for > can_split_huge_page()]
Acked-by: Johannes Weiner <[email protected]>
