This series extends the recently introduced trace remotes infrastructure, bringing useful features for developers:
* dump_on_panic: Dump the trace remote buffer on system panic. * dmesg: Redirect remote events to dmesg. * trace_remote=: Configure a trace_remote from the commandline. * poll_ms: Modify the polling period. It also brings a couple of optimisations: * In-header compressed length support for small events. * Single work thread for remote polling. And some misc improvements: * Use kstrtobool where possible * Free resources on remote registration failure Changelog: v5: * Use seq_buf_str() for safe, properly terminated trace_seq extraction. (Steven) * Remove destructive dmesg -c from selftests and rely on timestamp matching instead. (Steven) v4 (https://lore.kernel.org/all/[email protected]/): * Rebase on 7.2-rc6 * Use trace_append_boot_param() to parse cmdline options. * Fix trace_remote_iterator cleanup order for non-consuming iterators (Sashiko). v3 (https://lore.kernel.org/all/[email protected]/): * Make sure dmesg and panic handlers are using null-terminated trace_seq. * Make struct trace_remote more compact * Fix dump_on_panic test unloaded case (Sashiko) * Rebase on 7.2-rc4 v2 (https://lore.kernel.org/all/[email protected]/): Sashiko had a few spot-on comments on the v1 which forced me to heavily re-arrange the series, so I thought it'd be alright to send a v2 already including those changes. * dump_on_oops -> dump_on_panic * printk -> dmesg * Allow to configure poll_ms * Make the ring_buffer_iter functions panic-friendly * Gate tracefs .open on remote registration (Sashiko) * Use irqsave for reader lock (Sashiko) * Fix iter locking for TRI_DMESG (Sashiko) * Yield in the dmesg work (Sashiko) v1 (https://lore.kernel.org/all/[email protected]/) Vincent Donnefort (18): tracing/remotes: Gate tracefs files opening on trace remote registration tracing/remotes: Release tracefs,eventfs on registration failure tracing/remotes: Use kstrtobool for boolean tracefs files tracing/remotes: Use a single per-remote polling work tracing/simple_ring_buffer: Add support for compressed length tracing/remotes: Add dmesg tracefs file tracing/remotes: selftests: Add a test for the dmesg tracefs file tracing/remotes: selftests: Prefix hypervisor folder ring-buffer: Use irqsave for the reader lock in ring_buffer_poll_remote ring-buffer: Use panic-friendly locking in ring_buffer_iter interface ring-buffer: Add ring_buffer_read_remote_meta_page() ring-buffer: Add kerneldoc for ring_buffer_poll_remote tracing/remotes: Add dump_on_panic tracefs file tracing/remotes: selftests: Add a test for the dump_on_panic tracefs file tracing/remotes: Add poll_ms tracefs file tracing/remotes: Add trace_remote cmdline options Documentation: tracing/remotes: Add detailed tracefs layout Documentation/kernel-parameters: Add trace_remote .../admin-guide/kernel-parameters.txt | 19 + Documentation/trace/remotes.rst | 66 +- include/linux/ring_buffer.h | 1 + kernel/trace/ring_buffer.c | 88 +- kernel/trace/simple_ring_buffer.c | 25 +- kernel/trace/trace_remote.c | 817 +++++++++++++++--- .../buffer_size.tc | 0 .../test.d/remotes/00hypervisor/dmesg.tc | 11 + .../remotes/00hypervisor/dump_on_panic.tc | 11 + .../{hypervisor => 00hypervisor}/hotplug.tc | 0 .../{hypervisor => 00hypervisor}/reset.tc | 0 .../{hypervisor => 00hypervisor}/trace.tc | 0 .../trace_pipe.tc | 0 .../{hypervisor => 00hypervisor}/unloading.tc | 0 .../selftests/ftrace/test.d/remotes/dmesg.tc | 81 ++ .../ftrace/test.d/remotes/dump_on_panic.tc | 51 ++ .../selftests/ftrace/test.d/remotes/functions | 2 + 17 files changed, 1032 insertions(+), 140 deletions(-) rename tools/testing/selftests/ftrace/test.d/remotes/{hypervisor => 00hypervisor}/buffer_size.tc (100%) create mode 100644 tools/testing/selftests/ftrace/test.d/remotes/00hypervisor/dmesg.tc create mode 100644 tools/testing/selftests/ftrace/test.d/remotes/00hypervisor/dump_on_panic.tc rename tools/testing/selftests/ftrace/test.d/remotes/{hypervisor => 00hypervisor}/hotplug.tc (100%) rename tools/testing/selftests/ftrace/test.d/remotes/{hypervisor => 00hypervisor}/reset.tc (100%) rename tools/testing/selftests/ftrace/test.d/remotes/{hypervisor => 00hypervisor}/trace.tc (100%) rename tools/testing/selftests/ftrace/test.d/remotes/{hypervisor => 00hypervisor}/trace_pipe.tc (100%) rename tools/testing/selftests/ftrace/test.d/remotes/{hypervisor => 00hypervisor}/unloading.tc (100%) create mode 100644 tools/testing/selftests/ftrace/test.d/remotes/dmesg.tc create mode 100644 tools/testing/selftests/ftrace/test.d/remotes/dump_on_panic.tc base-commit: db2ddb87143519e20a95aa36c60b36107b736a58 -- 2.55.0.691.gc56d675ccc-goog
