fix: block: don't call blk_status_to_errno in blk_update_request (v5.16)

[lttng-modules.git] / README.md

diff --git a/README.md b/README.md
index 17553e63346d96dbbaef254eb3de3b13ebf5e509..fc083249cd5982b20dd1b0c9115ebda612868e72 100644 (file)
--- a/README.md
+++ b/README.md
@@ -66,6 +66,7 @@ Make sure your target kernel has the following config options enabled:
   - `CONFIG_TRACEPOINTS`: kernel tracepoint instrumentation
      (enabled as a side-effect of any of the perf/ftrace/blktrace
      instrumentation features).
+  - `CONFIG_KPROBES` (5.7+): use kallsyms for kernel 5.7 and newer.
 
 
 ### Supported (optional) kernel config options
@@ -94,6 +95,34 @@ available from LTTng:
   - `CONFIG_KALLSYMS_ALL`: state dump of mapping between block device
     number and name
 
+### LTTng specific kernel config options
+
+The following kernel configuration options are provided by LTTng:
+
+  - `CONFIG_LTTNG`: Build LTTng (Defaults to 'm').
+  - `CONFIG_LTTNG_EXPERIMENTAL_BITWISE_ENUM`: Enable the experimental bitwise
+    enumerations (Defaults to 'n'). This can be enabled by building with:
+
+         make CONFIG_LTTNG_EXPERIMENTAL_BITWISE_ENUM=y
+
+  - `CONFIG_LTTNG_CLOCK_PLUGIN_TEST`: Build the test clock plugin (Defaults to
+    'm'). This plugin overrides the trace clock and should always be built as a
+    module for testing.
+
+
+Customization/Extension
+-----------------------
+
+The lttng-modules source includes definitions for the actual callback
+functions that will be attached to the kernel tracepoints by lttng.
+The lttng-modules project implements its own macros generating these
+callbacks: the LTTNG_TRACEPOINT_EVENT macro family found in
+instrumentation/events/lttng-module/. In order to show up in a
+lttng-modules trace, a kernel tracepoint must be defined within the
+kernel tree, and also defined within lttng-modules with the
+LTTNG_TRACEPOINT_EVENT macro family. Customizations or extensions must
+be done by modifying instances of these macros within the lttng-modules
+source.
 
 Usage
 -----