Greetings: TLB shootdown events can be measured on a per-CPU basis by examining /proc/interrupts. Further information about TLB events can be harvested from /proc/vmstat if CONFIG_DEBUG_TLBFLUSH is enabled, but this information is system-wide. This information is useful, but on a busy system with many tasks it can be difficult to disambiguate the source of the TLB shootdown events. Having this information tracked per-task can enable developers to fix or tweak userland allocators to reduce the number of IPIs and improve application performance. This change adds two new fields to task_struct and signal_struct to help track TLB events: - ngtlbflush: number of tlb flushes generated - nrtlbflush: number of tlb flushes received These stats are exported in /proc/[pid]/stat alongside similar metrics (e.g. min_flt and maj_flt) for analysis. I've gotten code into kernel networking / drivers before, but I've never hacked on mm and mm-adjacent code before. Please let me know if there's a glaring issue and I'll be happy to tweak this code as necessary. If this seems OK, I'll send an official v1. Thanks! Joe Damato (1): mm: Add per-task struct tlb counters arch/x86/mm/tlb.c | 2 ++ fs/proc/array.c | 9 +++++++++ include/linux/sched.h | 6 ++++++ include/linux/sched/signal.h | 1 + kernel/exit.c | 6 ++++++ kernel/fork.c | 1 + 6 files changed, 25 insertions(+) -- 2.7.4
