d6a326d694
The __assign_str() macro logic of the TRACE_EVENT() macro was optimized so
that it no longer needs the second argument. The __assign_str() is always
matched with __string() field that takes a field name and the source for
that field:
__string(field, source)
The TRACE_EVENT() macro logic will save off the source value and then use
that value to copy into the ring buffer via the __assign_str(). Before
commit c1fa617caeb0 ("tracing: Rework __assign_str() and __string() to not
duplicate getting the string"), the __assign_str() needed the second
argument which would perform the same logic as the __string() source
parameter did. Not only would this add overhead, but it was error prone as
if the __assign_str() source produced something different, it may not have
allocated enough for the string in the ring buffer (as the __string()
source was used to determine how much to allocate)
Now that the __assign_str() just uses the same string that was used in
__string() it no longer needs the source parameter. It can now be removed.
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Merge tag 'trace-assign-str-v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing cleanup from Steven Rostedt:
"Remove second argument of __assign_str()
The __assign_str() macro logic of the TRACE_EVENT() macro was
optimized so that it no longer needs the second argument. The
__assign_str() is always matched with __string() field that takes a
field name and the source for that field:
__string(field, source)
The TRACE_EVENT() macro logic will save off the source value and then
use that value to copy into the ring buffer via the __assign_str().
Before commit c1fa617caeb0 ("tracing: Rework __assign_str() and
__string() to not duplicate getting the string"), the __assign_str()
needed the second argument which would perform the same logic as the
__string() source parameter did. Not only would this add overhead, but
it was error prone as if the __assign_str() source produced something
different, it may not have allocated enough for the string in the ring
buffer (as the __string() source was used to determine how much to
allocate)
Now that the __assign_str() just uses the same string that was used in
__string() it no longer needs the source parameter. It can now be
removed"
* tag 'trace-assign-str-v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing/treewide: Remove second parameter of __assign_str()
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.