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69a87a32f5
When 'perf record -d' is used, it needs data mmaps to symbolize global
data. But it missed to collect kernel data maps so it cannot symbolize
them. Instead of having a separate map, just increase the kernel map
size to include the data section.
Probably we can have a separate kernel map for data, but the current
code assumes a single kernel map. So it'd require more changes in other
places and looks error-prone. I decided not to go that way for now.
Also it seems the kernel module size already includes the data section.
For example, my system has the following.
$ grep -e _stext -e _etext -e _edata /proc/kallsyms
ffffffff99800000 T _stext
ffffffff9a601ac8 T _etext
ffffffff9b446a00 D _edata
Size of the text section is (0x9a601ac8 - 0x99800000 = 0xe01ac8) and
size including data section is (0x9b446a00 - 0x99800000 = 0x1c46a00).
Before:
$ perf record -d true
$ perf report -D | grep MMAP | head -1
0 0 0x460 [0x60]: PERF_RECORD_MMAP -1/0: [0xffffffff99800000(0xe01ac8) @ 0xffffffff99800000]: x [kernel.kallsyms]_text
^^^^^^^^
here
After:
$ perf report -D | grep MMAP | head -1
0 0 0x460 [0x60]: PERF_RECORD_MMAP -1/0: [0xffffffff99800000(0x1c46a00) @ 0xffffffff99800000]: x [kernel.kallsyms]_text
^^^^^^^^^
Instead of just replacing it to _edata, try _edata first and then fall
back to _etext just in case.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230725001929.368041-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
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the problems which may result by upgrading your kernel.