4.15 is now available in Bionic. Marking this Fix Released. ** Tags added: kernel
** Information type changed from Private to Public ** Also affects: linux (Ubuntu Bionic) Importance: Undecided Status: New ** Changed in: linux (Ubuntu Bionic) Status: New => Fix Released ** Changed in: intel Status: New => Fix Released -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1730879 Title: [Feature] Increase percpu counter threshold size Status in intel: Fix Released Status in linux package in Ubuntu: Fix Released Status in linux source package in Bionic: Fix Released Bug description: Description It was noted that the size of the percpu counters used for "node/zone_state" is only 8 bytes: struct per_cpu_pageset { struct per_cpu_pages pcp; s8 stat_threshold; s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS]; }; This code is very old. It effectively requires a pair hot, global cachelines to be touched when the per_cpu counter value does not fit in "vm_stat_diff". For this item, we need to increase the size of vm_stat_diff[] from an s8 to an s16, then allow the ->stat_threshold to be adjusted between the existing value of 125 and some larger value. Note that the current threshold from calculate_normal_threshold() is capped at 125 for all zones over 32GB. We have zones much larger than that today, so it is likely not scaling optimally. Target Kernel: 4.14 Target Release: 18.04 To manage notifications about this bug go to: https://bugs.launchpad.net/intel/+bug/1730879/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp