On Thu, Oct 12, 2017 at 10:30:57AM +0100, Mel Gorman wrote: > During truncation, the mapping has already been checked for shmem and dax > so it's known that workingset_update_node is required. This patch avoids > the checks on mapping for each page being truncated. In all other cases, > a lookup helper is used to determine if workingset_update_node() needs > to be called. The one danger is that the API is slightly harder to use as > calling workingset_update_node directly without checking for dax or shmem > mappings could lead to surprises. However, the API rarely needs to be used > and hopefully the comment is enough to give people the hint. > > sparsetruncate (tiny) > 4.14.0-rc4 4.14.0-rc4 > oneirq-v1r1 pickhelper-v1r1 > Min Time 141.00 ( 0.00%) 140.00 ( 0.71%) > 1st-qrtle Time 142.00 ( 0.00%) 141.00 ( 0.70%) > 2nd-qrtle Time 142.00 ( 0.00%) 142.00 ( 0.00%) > 3rd-qrtle Time 143.00 ( 0.00%) 143.00 ( 0.00%) > Max-90% Time 144.00 ( 0.00%) 144.00 ( 0.00%) > Max-95% Time 147.00 ( 0.00%) 145.00 ( 1.36%) > Max-99% Time 195.00 ( 0.00%) 191.00 ( 2.05%) > Max Time 230.00 ( 0.00%) 205.00 ( 10.87%) > Amean Time 144.37 ( 0.00%) 143.82 ( 0.38%) > Stddev Time 10.44 ( 0.00%) 9.00 ( 13.74%) > Coeff Time 7.23 ( 0.00%) 6.26 ( 13.41%) > Best99%Amean Time 143.72 ( 0.00%) 143.34 ( 0.26%) > Best95%Amean Time 142.37 ( 0.00%) 142.00 ( 0.26%) > Best90%Amean Time 142.19 ( 0.00%) 141.85 ( 0.24%) > Best75%Amean Time 141.92 ( 0.00%) 141.58 ( 0.24%) > Best50%Amean Time 141.69 ( 0.00%) 141.31 ( 0.27%) > Best25%Amean Time 141.38 ( 0.00%) 140.97 ( 0.29%) > > As you'd expect, the gain is marginal but it can be detected. The differences > in bonnie are all within the noise which is not surprising given the impact > on the microbenchmark. > > Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> With Jan's suggestion to remove the private parameter, Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> -- 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>
