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Thomas Richter f9b186caa0 perf annotate: Fix unnecessary memory allocation for s390x 
[ Upstream commit 36c263607d ]

This patch fixes a bug introduced with commit d9f8dfa9ba ("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>
History 2018-03-19 08:42:52 +01:00
arch ARM: dts: omap3-n900: Fix the audio CODEC's reset pin 2018-03-19 08:42:50 +01:00
block blk-mq: don't call io sched's .requeue_request when requeueing rq to ->dispatch 2018-03-08 22:41:20 -08:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto crypto: ecc - Fix NULL pointer deref. on no default_rng 2018-03-19 08:42:49 +01:00
Documentation usb: host: xhci-rcar: add support for r8a77965 2018-03-19 08:42:45 +01:00
drivers pinctrl: sh-pfc: r8a7795-es1: Fix MOD_SEL1 bit[25:24] to 0x3 when using STP_ISEN_1_D 2018-03-19 08:42:52 +01:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs userns: Don't fail follow_automount based on s_user_ns 2018-03-19 08:42:50 +01:00
include dma-buf/fence: Fix lock inversion within dma-fence-array 2018-03-19 08:42:47 +01:00
init kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK 2018-02-22 15:42:23 +01:00
ipc License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kernel sched: Stop resched_cpu() from sending IPIs to offline CPUs 2018-03-19 08:42:49 +01:00
lib lib/bug.c: exclude non-BUG/WARN exceptions from report_bug() 2018-03-15 10:54:32 +01:00
mm mm/memblock.c: hardcode the end_pfn being -1 2018-03-15 10:54:32 +01:00
net xfrm: Fix xfrm_replay_overflow_offload_esn 2018-03-19 08:42:50 +01:00
samples samples/bpf: adjust rlimit RLIMIT_MEMLOCK for xdp1 2017-12-20 10:10:31 +01:00
scripts objtool, retpolines: Integrate objtool with retpoline support more closely 2018-03-15 10:54:38 +01:00
security selinux: skip bounded transition processing if the policy isn't loaded 2018-02-25 11:07:49 +01:00
sound ASoC: rt5651: Fix regcache sync errors on resume 2018-03-19 08:42:44 +01:00
tools perf annotate: Fix unnecessary memory allocation for s390x 2018-03-19 08:42:52 +01:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM: mmu: Fix overlap between public and private memslots 2018-03-08 22:41:24 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: rpm-pkg: keep spec file until make mrproper 2018-02-13 10:19:46 +01:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING [PATCH] update FSF address in COPYING 2005-09-10 10:06:29 -07:00
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS dt-bindings: Document mti,mips-cpc binding 2018-03-15 10:54:35 +01:00
Makefile Linux 4.14.27 2018-03-15 10:54:38 +01:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README 

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.