perf: Add 'perf kmem' tool

perf: Add 'perf kmem' tool

This tool is mostly a perf version of kmemtrace-user.

The following information is provided by this tool:

 - the total amount of memory allocated and fragmentation per
   call-site

 - the total amount of memory allocated and fragmentation per
   allocation

 - total memory allocated and fragmentation in the collected
   dataset - ...

Sample output:

 # ./perf kmem record
 ^C
 # ./perf kmem --stat caller --stat alloc -l 10

 ------------------------------------------------------------------------------
 Callsite          | Total_alloc/Per |  Total_req/Per  |  Hit   | Fragmentation
 ------------------------------------------------------------------------------
 0xc052f37a        |   790528/4096   |   790528/4096   |    193 |    0.000%
 0xc0541d70        |   524288/4096   |   524288/4096   |    128 |    0.000%
 0xc051cc68        |   481600/200    |   481600/200    |   2408 |    0.000%
 0xc0572623        |   297444/676    |   297440/676    |    440 |    0.001%
 0xc05399f1        |    73476/164    |    73472/164    |    448 |    0.005%
 0xc05243bf        |    51456/256    |    51456/256    |    201 |    0.000%
 0xc0730d0e        |    31844/497    |    31808/497    |     64 |    0.113%
 0xc0734c4e        |    17152/256    |    17152/256    |     67 |    0.000%
 0xc0541a6d        |    16384/128    |    16384/128    |    128 |    0.000%
 0xc059c217        |    13120/40     |    13120/40     |    328 |    0.000%
 0xc0501ee6        |    11264/88     |    11264/88     |    128 |    0.000%
 0xc04daef0        |     7504/682    |     7128/648    |     11 |    5.011%
 0xc04e14a3        |     4216/191    |     4216/191    |     22 |    0.000%
 0xc05041ca        |     3524/44     |     3520/44     |     80 |    0.114%
 0xc0734fa3        |     2104/701    |     1620/540    |      3 |   23.004%
 0xc05ec9f1        |     2024/289    |     2016/288    |      7 |    0.395%
 0xc06a1999        |     1792/256    |     1792/256    |      7 |    0.000%
 0xc0463b9a        |     1584/144    |     1584/144    |     11 |    0.000%
 0xc0541eb0        |     1024/16     |     1024/16     |     64 |    0.000%
 0xc06a19ac        |      896/128    |      896/128    |      7 |    0.000%
 0xc05721c0        |      772/12     |      768/12     |     64 |    0.518%
 0xc054d1e6        |      288/57     |      280/56     |      5 |    2.778%
 0xc04b562e        |      157/31     |      154/30     |      5 |    1.911%
 0xc04b536f        |       80/16     |       80/16     |      5 |    0.000%
 0xc05855a0        |       64/64     |       36/36     |      1 |   43.750%
 ------------------------------------------------------------------------------

 ------------------------------------------------------------------------------
 Alloc Ptr         | Total_alloc/Per |  Total_req/Per  |  Hit   | Fragmentation
 ------------------------------------------------------------------------------
 0xda884000        |  1052672/4096   |  1052672/4096   |    257 |    0.000%
 0xda886000        |   262144/4096   |   262144/4096   |     64 |    0.000%
 0xf60c7c00        |    16512/128    |    16512/128    |    129 |    0.000%
 0xf59a4118        |    13120/40     |    13120/40     |    328 |    0.000%
 0xdfd4b2c0        |    11264/88     |    11264/88     |    128 |    0.000%
 0xf5274600        |     7680/256    |     7680/256    |     30 |    0.000%
 0xe8395000        |     5948/594    |     5464/546    |     10 |    8.137%
 0xe59c3c00        |     5748/479    |     5712/476    |     12 |    0.626%
 0xf4cd1a80        |     3524/44     |     3520/44     |     80 |    0.114%
 0xe5bd1600        |     2892/482    |     2856/476    |      6 |    1.245%
 ...               | ...             | ...             | ...    | ...
 ------------------------------------------------------------------------------

SUMMARY
=======
Total bytes requested: 2333626
Total bytes allocated: 2353712
Total bytes wasted on internal fragmentation: 20086
Internal fragmentation: 0.853375%

TODO:
- show sym+offset in 'callsite' column
- show cross node allocation stats
- collect more useful stats?
- ...

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: linux-mm@kvack.org <linux-mm@kvack.org>
LKML-Reference: <4B064AF5.9060208@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>