On Sat, Sep 05, 2026 at 07:27:30PM +0800, Xiang Gao wrote: > Report the memory consumed by the tracing ring buffers, rather than the > usable data capacity exposed by buffer_size_kb. Android low-memory > diagnostics need this to attribute the memory used by tracing when > calculating lost RAM. > > The buffers can be spread across the global trace array, dynamically > created instances, and snapshot buffers. Userspace currently has to > discover and sum every instance, and snapshot memory is not exposed by > the per-instance totals. > > Patch 1 adds: > > /sys/kernel/tracing/trace_stats/memory_usage_kb > > reporting: > > buffers: ... > snapshot_buffers: ... > > covering the global trace array and all instances across all CPUs. > > Patch 2 adds the per-CPU view under > trace_stats/per_cpu/cpuN/memory_usage_kb. > > The values account for the full pages backing the data sub-buffers and > reader page, plus the cached read page and mmap metadata page when > present. Slab-allocated ring-buffer metadata is not included. > > Xiang Gao (2): > tracing: add ring-buffer memory usage statistics in tracefs > tracing: add per-CPU memory usage statistics in tracefs > > Documentation/trace/ftrace.rst | 15 +++++ > include/linux/ring_buffer.h | 1 + > kernel/trace/ring_buffer.c | 41 +++++++++++++ > kernel/trace/trace.c | 104 +++++++++++++++++++++++++++++++++ > 4 files changed, 161 insertions(+) > > -- > 2.34.1 > >
It looks like you have sent the same v1 again. -- Vincent
