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(+)
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2.7.4