I confirm that reverting the SLAB / SLUB changes in the ubuntu kernel configuration file for mainline kernel 4.8-rc7 to the state they were in for mainline kernel 4.7-rc4 fixes the issue (note, I disable debug, because otherwise it takes over twice as long to compile the kernel, and it is enormous):
$ scripts/diffconfig .config .config-4.8.0-040800rc7-generic -HAVE_ALIGNED_STRUCT_PAGE y -SLUB_CPU_PARTIAL y -SLUB_DEBUG y -SLUB_DEBUG_ON n -SLUB_STATS n DEBUG_INFO n -> y SLAB n -> y SLAB_FREELIST_RANDOM n -> y SLUB y -> n +DEBUG_INFO_DWARF4 n +DEBUG_INFO_REDUCED n +DEBUG_INFO_SPLIT n +DEBUG_SLAB n +GDB_SCRIPTS n -- 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/1626564 Title: 4.8 regression: SLAB is being used instead of SLUB Status in linux package in Ubuntu: Fix Committed Status in linux source package in Yakkety: Fix Committed Bug description: We're seeing hundreds of kernel worker threads being spawned with some actions, for example, after booting the desktop and hutting the brightness keys causes this. On investigation, this occurs when CONFIG_SLAB is being used. 1. Ubuntu traditionally uses CONFIG_SLUB, so we should use that instead of CONFIG_SLAB (why was it changed for Yakkety?) 2. With CONFIG_SLUB I cannot reproduce the issue of the hundreds for worker threads 3 CONFIG_SLUB seems more performant on the boot too over SLAB. Please re-enable the CONFIG_SLUB allocator as per the 4.4. Xenial configs. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1626564/+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
