f9b186caa0
[ Upstream commit 36c263607d36c6a3788c09301d9f5fe35404048a ]
This patch fixes a bug introduced with commit d9f8dfa9baf9 ("perf
annotate s390: Implement jump types for perf annotate").
'perf annotate' displays annotated assembler output by reading output of
command objdump and parsing the disassembled lines. For each shown
mnemonic this function sequence is executed:
disasm_line__new()
|
+--> disasm_line__init_ins()
|
+--> ins__find()
|
+--> arch->associate_instruction_ops()
The s390x specific function assigned to function pointer
associate_instruction_ops refers to function s390__associate_ins_ops().
This function checks for supported mnemonics and assigns a NULL pointer
to unsupported mnemonics. However even the NULL pointer is added to the
architecture dependend instruction array.
This leads to an extremely large architecture instruction array
(due to array resize logic in function arch__grow_instructions()).
Depending on the objdump output being parsed the array can end up
with several ten-thousand elements.
This patch checks if a mnemonic is supported and only adds supported
ones into the architecture instruction array. The array does not contain
elements with NULL pointers anymore.
Before the patch (With some debug printf output):
[root@s35lp76 perf]# time ./perf annotate --stdio > /tmp/xxxbb
real 8m49.679s
user 7m13.008s
sys 0m1.649s
[root@s35lp76 perf]# fgrep '__ins__find sorted:1 nr_instructions:'
/tmp/xxxbb | tail -1
__ins__find sorted:1 nr_instructions:87433 ins:0x341583c0
[root@s35lp76 perf]#
The number of different s390x branch/jump/call/return instructions
entered into the array is 87433.
After the patch (With some printf debug output:)
[root@s35lp76 perf]# time ./perf annotate --stdio > /tmp/xxxaa
real 1m24.553s
user 0m0.587s
sys 0m1.530s
[root@s35lp76 perf]# fgrep '__ins__find sorted:1 nr_instructions:'
/tmp/xxxaa | tail -1
__ins__find sorted:1 nr_instructions:56 ins:0x3f406570
[root@s35lp76 perf]#
The number of different s390x branch/jump/call/return instructions
entered into the array is 56 which is sensible.
Signed-off-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: http://lkml.kernel.org/r/20171124094637.55558-1-tmricht@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.