On Tue 24-01-17 15:49:01, Jia He wrote: > If there is a server with uneven numa memory layout: > available: 7 nodes (0-6) > node 0 cpus: 0 1 2 3 4 5 6 7 > node 0 size: 6603 MB > node 0 free: 91 MB > node 1 cpus: > node 1 size: 12527 MB > node 1 free: 157 MB > node 2 cpus: > node 2 size: 15087 MB > node 2 free: 189 MB > node 3 cpus: > node 3 size: 16111 MB > node 3 free: 205 MB > node 4 cpus: 8 9 10 11 12 13 14 15 > node 4 size: 24815 MB > node 4 free: 310 MB > node 5 cpus: > node 5 size: 4095 MB > node 5 free: 61 MB > node 6 cpus: > node 6 size: 22750 MB > node 6 free: 283 MB > node distances: > node 0 1 2 3 4 5 6 > 0: 10 20 40 40 40 40 40 > 1: 20 10 40 40 40 40 40 > 2: 40 40 10 20 40 40 40 > 3: 40 40 20 10 40 40 40 > 4: 40 40 40 40 10 20 40 > 5: 40 40 40 40 20 10 40 > 6: 40 40 40 40 40 40 10 > > In this case node 5 has less memory and we will alloc the hugepages > from these nodes one by one after we trigger > echo 4000 > /proc/sys/vm/nr_hugepages > > Then the kswapd5 will take 100% cpu for a long time. This is a livelock > issue in kswapd. This patch set fixes it. It would be really helpful to describe what is the issue and whether it is specific to the configuration above. Also a highlevel overview of the fix and why it is the right approach would be appreciated. > The 3rd patch improves the kswapd's bad performance significantly. Numbers? > Jia He (3): > mm/hugetlb: split alloc_fresh_huge_page_node into fast and slow path > mm, vmscan: limit kswapd loop if no progress is made > mm, vmscan: correct prepare_kswapd_sleep return value > > mm/hugetlb.c | 9 +++++++++ > mm/vmscan.c | 28 ++++++++++++++++++++++++---- > 2 files changed, 33 insertions(+), 4 deletions(-) > > -- > 2.5.5 > -- Michal Hocko 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>
