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authorLinus Torvalds <torvalds@linux-foundation.org>2024-03-18 15:11:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2024-03-18 15:11:44 -0700
commitad584d73a22b2f6e6b4c928956fdece5c44cdb3e (patch)
tree2ed321145a24ed5a1d9a43adb256025e0f38ceee /samples
parent2cb5c8683981ebd5033e3cc91f7dd75794f16e61 (diff)
parent7604256cecef34a82333d9f78262d3180f4eb525 (diff)
Merge tag 'trace-v6.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing updates from Steven Rostedt: "Main user visible change: - User events can now have "multi formats" The current user events have a single format. If another event is created with a different format, it will fail to be created. That is, once an event name is used, it cannot be used again with a different format. This can cause issues if a library is using an event and updates its format. An application using the older format will prevent an application using the new library from registering its event. A task could also DOS another application if it knows the event names, and it creates events with different formats. The multi-format event is in a different name space from the single format. Both the event name and its format are the unique identifier. This will allow two different applications to use the same user event name but with different payloads. - Added support to have ftrace_dump_on_oops dump out instances and not just the main top level tracing buffer. Other changes: - Add eventfs_root_inode Only the root inode has a dentry that is static (never goes away) and stores it upon creation. There's no reason that the thousands of other eventfs inodes should have a pointer that never gets set in its descriptor. Create a eventfs_root_inode desciptor that has a eventfs_inode descriptor and a dentry pointer, and only the root inode will use this. - Added WARN_ON()s in eventfs There's some conditionals remaining in eventfs that should never be hit, but instead of removing them, add WARN_ON() around them to make sure that they are never hit. - Have saved_cmdlines allocation also include the map_cmdline_to_pid array The saved_cmdlines structure allocates a large amount of data to hold its mappings. Within it, it has three arrays. Two are already apart of it: map_pid_to_cmdline[] and saved_cmdlines[]. More memory can be saved by also including the map_cmdline_to_pid[] array as well. - Restructure __string() and __assign_str() macros used in TRACE_EVENT() Dynamic strings in TRACE_EVENT() are declared with: __string(name, source) And assigned with: __assign_str(name, source) In the tracepoint callback of the event, the __string() is used to get the size needed to allocate on the ring buffer and __assign_str() is used to copy the string into the ring buffer. There's a helper structure that is created in the TRACE_EVENT() macro logic that will hold the string length and its position in the ring buffer which is created by __string(). There are several trace events that have a function to create the string to save. This function is executed twice. Once for __string() and again for __assign_str(). There's no reason for this. The helper structure could also save the string it used in __string() and simply copy that into __assign_str() (it also already has its length). By using the structure to store the source string for the assignment, it means that the second argument to __assign_str() is no longer needed. It will be removed in the next merge window, but for now add a warning if the source string given to __string() is different than the source string given to __assign_str(), as the source to __assign_str() isn't even used and will be going away. - Added checks to make sure that the source of __string() is also the source of __assign_str() so that it can be safely removed in the next merge window. Included fixes that the above check found. - Other minor clean ups and fixes" * tag 'trace-v6.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (34 commits) tracing: Add __string_src() helper to help compilers not to get confused tracing: Use strcmp() in __assign_str() WARN_ON() check tracepoints: Use WARN() and not WARN_ON() for warnings tracing: Use div64_u64() instead of do_div() tracing: Support to dump instance traces by ftrace_dump_on_oops tracing: Remove second parameter to __assign_rel_str() tracing: Add warning if string in __assign_str() does not match __string() tracing: Add __string_len() example tracing: Remove __assign_str_len() ftrace: Fix most kernel-doc warnings tracing: Decrement the snapshot if the snapshot trigger fails to register tracing: Fix snapshot counter going between two tracers that use it tracing: Use EVENT_NULL_STR macro instead of open coding "(null)" tracing: Use ? : shortcut in trace macros tracing: Do not calculate strlen() twice for __string() fields tracing: Rework __assign_str() and __string() to not duplicate getting the string cxl/trace: Properly initialize cxl_poison region name net: hns3: tracing: fix hclgevf trace event strings drm/i915: Add missing ; to __assign_str() macros in tracepoint code NFSD: Fix nfsd_clid_class use of __string_len() macro ...
Diffstat (limited to 'samples')
-rw-r--r--samples/trace_events/trace-events-sample.h18
1 files changed, 11 insertions, 7 deletions
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 23f923ccd529..500981eca74d 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -163,8 +163,7 @@
* __string().
*
* __string_len: This is a helper to a __dynamic_array, but it understands
- * that the array has characters in it, and with the combined
- * use of __assign_str_len(), it will allocate 'len' + 1 bytes
+ * that the array has characters in it, it will allocate 'len' + 1 bytes
* in the ring buffer and add a '\0' to the string. This is
* useful if the string being saved has no terminating '\0' byte.
* It requires that the length of the string is known as it acts
@@ -174,9 +173,11 @@
*
* __string_len(foo, bar, len)
*
- * To assign this string, use the helper macro __assign_str_len().
+ * To assign this string, use the helper macro __assign_str().
+ * The length is saved via the __string_len() and is retrieved in
+ * __assign_str().
*
- * __assign_str_len(foo, bar, len);
+ * __assign_str(foo, bar);
*
* Then len + 1 is allocated to the ring buffer, and a nul terminating
* byte is added. This is similar to:
@@ -302,6 +303,7 @@ TRACE_EVENT(foo_bar,
__bitmask( cpus, num_possible_cpus() )
__cpumask( cpum )
__vstring( vstr, fmt, va )
+ __string_len( lstr, foo, bar / 2 < strlen(foo) ? bar / 2 : strlen(foo) )
),
TP_fast_assign(
@@ -310,12 +312,13 @@ TRACE_EVENT(foo_bar,
memcpy(__get_dynamic_array(list), lst,
__length_of(lst) * sizeof(int));
__assign_str(str, string);
+ __assign_str(lstr, foo);
__assign_vstr(vstr, fmt, va);
__assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus());
__assign_cpumask(cpum, cpumask_bits(mask));
),
- TP_printk("foo %s %d %s %s %s %s (%s) (%s) %s", __entry->foo, __entry->bar,
+ TP_printk("foo %s %d %s %s %s %s %s (%s) (%s) %s", __entry->foo, __entry->bar,
/*
* Notice here the use of some helper functions. This includes:
@@ -359,7 +362,8 @@ TRACE_EVENT(foo_bar,
__print_array(__get_dynamic_array(list),
__get_dynamic_array_len(list) / sizeof(int),
sizeof(int)),
- __get_str(str), __get_bitmask(cpus), __get_cpumask(cpum),
+ __get_str(str), __get_str(lstr),
+ __get_bitmask(cpus), __get_cpumask(cpum),
__get_str(vstr))
);
@@ -570,7 +574,7 @@ TRACE_EVENT(foo_rel_loc,
),
TP_fast_assign(
- __assign_rel_str(foo, foo);
+ __assign_rel_str(foo);
__entry->bar = bar;
__assign_rel_bitmask(bitmask, mask,
BITS_PER_BYTE * sizeof(unsigned long));