<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/drivers/block/zram, branch v4.15</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>drivers/block/zram/zram_drv.c: make zram_page_end_io() static</title>
<updated>2017-11-16T02:21:05+00:00</updated>
<author>
<name>Colin Ian King</name>
<email>colin.king@canonical.com</email>
</author>
<published>2017-11-16T01:37:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=384bc41fc064bd8b12b7081aa3e81d26f3407045'/>
<id>384bc41fc064bd8b12b7081aa3e81d26f3407045</id>
<content type='text'>
zram_page_end_io() is local to the source and does not need to be in
global scope, so make it static.

Cleans up sparse warning:

  symbol 'zram_page_end_io' was not declared. Should it be static?

Link: http://lkml.kernel.org/r/20171016173336.20320-1-colin.king@canonical.com
Signed-off-by: Colin Ian King &lt;colin.king@canonical.com&gt;
Reviewed-by: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
zram_page_end_io() is local to the source and does not need to be in
global scope, so make it static.

Cleans up sparse warning:

  symbol 'zram_page_end_io' was not declared. Should it be static?

Link: http://lkml.kernel.org/r/20171016173336.20320-1-colin.king@canonical.com
Signed-off-by: Colin Ian King &lt;colin.king@canonical.com&gt;
Reviewed-by: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>zram: remove zlib from the list of recommended algorithms</title>
<updated>2017-11-16T02:21:03+00:00</updated>
<author>
<name>Sergey Senozhatsky</name>
<email>sergey.senozhatsky.work@gmail.com</email>
</author>
<published>2017-11-16T01:33:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=0b07ff3972061a5e06e168378dd578801ae3e88e'/>
<id>0b07ff3972061a5e06e168378dd578801ae3e88e</id>
<content type='text'>
ZSTD tends to outperform deflate/inflate, thus we remove zlib from the
list of recommended algorithms and recommend zstd instead.

Link: http://lkml.kernel.org/r/20170912050005.3247-2-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Suggested-by: Minchan Kim &lt;minchan@kernel.org&gt;
Acked-by: Minchan Kim &lt;minchan@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
ZSTD tends to outperform deflate/inflate, thus we remove zlib from the
list of recommended algorithms and recommend zstd instead.

Link: http://lkml.kernel.org/r/20170912050005.3247-2-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Suggested-by: Minchan Kim &lt;minchan@kernel.org&gt;
Acked-by: Minchan Kim &lt;minchan@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>zram: add zstd to the supported algorithms list</title>
<updated>2017-11-16T02:21:03+00:00</updated>
<author>
<name>Sergey Senozhatsky</name>
<email>sergey.senozhatsky.work@gmail.com</email>
</author>
<published>2017-11-16T01:33:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=5ef3a8b12556d7fcba81edc74e9d85b029615ae0'/>
<id>5ef3a8b12556d7fcba81edc74e9d85b029615ae0</id>
<content type='text'>
Add ZSTD to the list of supported compression algorithms.

ZRAM fio perf test:

                      LZO         DEFLATE         ZSTD

#jobs1
WRITE:              (2180MB/s)   (77.2MB/s)      (1429MB/s)
WRITE:              (1617MB/s)   (77.7MB/s)      (1202MB/s)
READ:                (426MB/s)   (595MB/s)       (1181MB/s)
READ:                (422MB/s)   (572MB/s)       (1020MB/s)
READ:                (318MB/s)   (67.8MB/s)      (563MB/s)
WRITE:               (318MB/s)   (67.9MB/s)      (564MB/s)
READ:                (336MB/s)   (68.3MB/s)      (583MB/s)
WRITE:               (335MB/s)   (68.2MB/s)      (582MB/s)
#jobs2
WRITE:              (3441MB/s)   (152MB/s)       (2141MB/s)
WRITE:              (2507MB/s)   (147MB/s)       (1888MB/s)
READ:                (801MB/s)   (1146MB/s)      (1890MB/s)
READ:                (767MB/s)   (1096MB/s)      (2073MB/s)
READ:                (621MB/s)   (126MB/s)       (1009MB/s)
WRITE:               (621MB/s)   (126MB/s)       (1009MB/s)
READ:                (656MB/s)   (125MB/s)       (1075MB/s)
WRITE:               (657MB/s)   (126MB/s)       (1077MB/s)
#jobs3
WRITE:              (4772MB/s)   (225MB/s)       (3394MB/s)
WRITE:              (3905MB/s)   (211MB/s)       (2939MB/s)
READ:               (1216MB/s)   (1608MB/s)      (3218MB/s)
READ:               (1159MB/s)   (1431MB/s)      (2981MB/s)
READ:                (906MB/s)   (156MB/s)       (1457MB/s)
WRITE:               (907MB/s)   (156MB/s)       (1458MB/s)
READ:                (953MB/s)   (158MB/s)       (1595MB/s)
WRITE:               (952MB/s)   (157MB/s)       (1593MB/s)
#jobs4
WRITE:              (6036MB/s)   (265MB/s)       (4469MB/s)
WRITE:              (5059MB/s)   (263MB/s)       (3951MB/s)
READ:               (1618MB/s)   (2066MB/s)      (4276MB/s)
READ:               (1573MB/s)   (1942MB/s)      (3830MB/s)
READ:               (1202MB/s)   (227MB/s)       (1971MB/s)
WRITE:              (1200MB/s)   (227MB/s)       (1968MB/s)
READ:               (1265MB/s)   (226MB/s)       (2116MB/s)
WRITE:              (1264MB/s)   (226MB/s)       (2114MB/s)
#jobs5
WRITE:              (5339MB/s)   (233MB/s)       (3781MB/s)
WRITE:              (4298MB/s)   (234MB/s)       (3276MB/s)
READ:               (1626MB/s)   (2048MB/s)      (4081MB/s)
READ:               (1567MB/s)   (1929MB/s)      (3758MB/s)
READ:               (1174MB/s)   (205MB/s)       (1747MB/s)
WRITE:              (1173MB/s)   (204MB/s)       (1746MB/s)
READ:               (1214MB/s)   (208MB/s)       (1890MB/s)
WRITE:              (1215MB/s)   (208MB/s)       (1892MB/s)
#jobs6
WRITE:              (5666MB/s)   (270MB/s)       (4338MB/s)
WRITE:              (4828MB/s)   (267MB/s)       (3772MB/s)
READ:               (1803MB/s)   (2058MB/s)      (4946MB/s)
READ:               (1805MB/s)   (2156MB/s)      (4711MB/s)
READ:               (1334MB/s)   (235MB/s)       (2135MB/s)
WRITE:              (1335MB/s)   (235MB/s)       (2137MB/s)
READ:               (1364MB/s)   (236MB/s)       (2268MB/s)
WRITE:              (1365MB/s)   (237MB/s)       (2270MB/s)
#jobs7
WRITE:              (5474MB/s)   (270MB/s)       (4300MB/s)
WRITE:              (4666MB/s)   (266MB/s)       (3817MB/s)
READ:               (2022MB/s)   (2319MB/s)      (5472MB/s)
READ:               (1924MB/s)   (2260MB/s)      (5031MB/s)
READ:               (1369MB/s)   (242MB/s)       (2153MB/s)
WRITE:              (1370MB/s)   (242MB/s)       (2155MB/s)
READ:               (1499MB/s)   (246MB/s)       (2310MB/s)
WRITE:              (1497MB/s)   (246MB/s)       (2307MB/s)
#jobs8
WRITE:              (5558MB/s)   (273MB/s)       (4439MB/s)
WRITE:              (4763MB/s)   (271MB/s)       (3918MB/s)
READ:               (2201MB/s)   (2599MB/s)      (6062MB/s)
READ:               (2105MB/s)   (2463MB/s)      (5413MB/s)
READ:               (1490MB/s)   (252MB/s)       (2238MB/s)
WRITE:              (1488MB/s)   (252MB/s)       (2236MB/s)
READ:               (1566MB/s)   (254MB/s)       (2434MB/s)
WRITE:              (1568MB/s)   (254MB/s)       (2437MB/s)
#jobs9
WRITE:              (5120MB/s)   (264MB/s)       (4035MB/s)
WRITE:              (4531MB/s)   (267MB/s)       (3740MB/s)
READ:               (1940MB/s)   (2258MB/s)      (4986MB/s)
READ:               (2024MB/s)   (2387MB/s)      (4871MB/s)
READ:               (1343MB/s)   (246MB/s)       (2038MB/s)
WRITE:              (1342MB/s)   (246MB/s)       (2037MB/s)
READ:               (1553MB/s)   (238MB/s)       (2243MB/s)
WRITE:              (1552MB/s)   (238MB/s)       (2242MB/s)
#jobs10
WRITE:              (5345MB/s)   (271MB/s)       (3988MB/s)
WRITE:              (4750MB/s)   (254MB/s)       (3668MB/s)
READ:               (1876MB/s)   (2363MB/s)      (5150MB/s)
READ:               (1990MB/s)   (2256MB/s)      (5080MB/s)
READ:               (1355MB/s)   (250MB/s)       (2019MB/s)
WRITE:              (1356MB/s)   (251MB/s)       (2020MB/s)
READ:               (1490MB/s)   (252MB/s)       (2202MB/s)
WRITE:              (1488MB/s)   (252MB/s)       (2199MB/s)

jobs1                              perfstat
instructions                 52,065,555,710 (    0.79)    855,731,114,587 (    2.64)       54,280,709,944 (    1.40)
branches                     14,020,427,116 ( 725.847)    101,733,449,582 (1074.521)       11,170,591,067 ( 992.869)
branch-misses                    22,626,174 (   0.16%)        274,197,885 (   0.27%)           25,915,805 (   0.23%)
jobs2                              perfstat
instructions                103,633,110,402 (    0.75)  1,710,822,100,914 (    2.59)      107,879,874,104 (    1.28)
branches                     27,931,237,282 ( 679.203)    203,298,267,479 (1037.326)       22,185,350,842 ( 884.427)
branch-misses                    46,103,811 (   0.17%)        533,747,204 (   0.26%)           49,682,483 (   0.22%)
jobs3                              perfstat
instructions                154,857,283,657 (    0.76)  2,565,748,974,197 (    2.57)      161,515,435,813 (    1.31)
branches                     41,759,490,355 ( 670.529)    304,905,605,277 ( 978.765)       33,215,805,907 ( 888.003)
branch-misses                    74,263,293 (   0.18%)        759,746,240 (   0.25%)           76,841,196 (   0.23%)
jobs4                              perfstat
instructions                206,215,849,076 (    0.75)  3,420,169,460,897 (    2.60)      215,003,061,664 (    1.31)
branches                     55,632,141,739 ( 666.501)    406,394,977,433 ( 927.241)       44,214,322,251 ( 883.532)
branch-misses                   102,287,788 (   0.18%)      1,098,617,314 (   0.27%)          103,891,040 (   0.23%)
jobs5                              perfstat
instructions                258,711,315,588 (    0.67)  4,275,657,533,244 (    2.23)      269,332,235,685 (    1.08)
branches                     69,802,821,166 ( 588.823)    507,996,211,252 ( 797.036)       55,450,846,129 ( 735.095)
branch-misses                   129,217,214 (   0.19%)      1,243,284,991 (   0.24%)          173,512,278 (   0.31%)
jobs6                              perfstat
instructions                312,796,166,008 (    0.61)  5,133,896,344,660 (    2.02)      323,658,769,588 (    1.04)
branches                     84,372,488,583 ( 520.541)    610,310,494,402 ( 697.642)       66,683,292,992 ( 693.939)
branch-misses                   159,438,978 (   0.19%)      1,396,368,563 (   0.23%)          174,406,934 (   0.26%)
jobs7                              perfstat
instructions                363,211,372,930 (    0.56)  5,988,205,600,879 (    1.75)      377,824,674,156 (    0.93)
branches                     98,057,013,765 ( 463.117)    711,841,255,974 ( 598.762)       77,879,009,954 ( 600.443)
branch-misses                   199,513,153 (   0.20%)      1,507,651,077 (   0.21%)          248,203,369 (   0.32%)
jobs8                              perfstat
instructions                413,960,354,615 (    0.52)  6,842,918,558,378 (    1.45)      431,938,486,581 (    0.83)
branches                    111,812,574,884 ( 414.224)    813,299,084,518 ( 491.173)       89,062,699,827 ( 517.795)
branch-misses                   233,584,845 (   0.21%)      1,531,593,921 (   0.19%)          286,818,489 (   0.32%)
jobs9                              perfstat
instructions                465,976,220,300 (    0.53)  7,698,467,237,372 (    1.47)      486,352,600,321 (    0.84)
branches                    125,931,456,162 ( 424.063)    915,207,005,715 ( 498.192)      100,370,404,090 ( 517.439)
branch-misses                   256,992,445 (   0.20%)      1,782,809,816 (   0.19%)          345,239,380 (   0.34%)
jobs10                             perfstat
instructions                517,406,372,715 (    0.53)  8,553,527,312,900 (    1.48)      540,732,653,094 (    0.84)
branches                    139,839,780,676 ( 427.732)  1,016,737,699,389 ( 503.172)      111,696,557,638 ( 516.750)
branch-misses                   259,595,561 (   0.19%)      1,952,570,279 (   0.19%)          357,818,661 (   0.32%)

seconds elapsed        20.630411534     96.084546565    12.743373571
seconds elapsed        22.292627625     100.984155001   14.407413560
seconds elapsed        22.396016966     110.344880848   14.032201392
seconds elapsed        22.517330949     113.351459170   14.243074935
seconds elapsed        28.548305104     156.515193765   19.159286861
seconds elapsed        30.453538116     164.559937678   19.362492717
seconds elapsed        33.467108086     188.486827481   21.492612173
seconds elapsed        35.617727591     209.602677783   23.256422492
seconds elapsed        42.584239509     243.959902566   28.458540338
seconds elapsed        47.683632526     269.635248851   31.542404137

Over all, ZSTD has slower WRITE, but much faster READ (perhaps
a static compression buffer used during the test helped ZSTD a
lot), which results in faster test results.

Memory consumption (zram mm_stat file):

zram LZO mm_stat
mm_stat (jobs1): 2147483648 23068672 33558528        0 33558528        0        0
mm_stat (jobs2): 2147483648 23068672 33558528        0 33558528        0        0
mm_stat (jobs3): 2147483648 23068672 33558528        0 33562624        0        0
mm_stat (jobs4): 2147483648 23068672 33558528        0 33558528        0        0
mm_stat (jobs5): 2147483648 23068672 33558528        0 33558528        0        0
mm_stat (jobs6): 2147483648 23068672 33558528        0 33562624        0        0
mm_stat (jobs7): 2147483648 23068672 33558528        0 33566720        0        0
mm_stat (jobs8): 2147483648 23068672 33558528        0 33558528        0        0
mm_stat (jobs9): 2147483648 23068672 33558528        0 33558528        0        0
mm_stat (jobs10): 2147483648 23068672 33558528        0 33562624        0        0

zram DEFLATE mm_stat
mm_stat (jobs1): 2147483648 16252928 25178112        0 25178112        0        0
mm_stat (jobs2): 2147483648 16252928 25178112        0 25178112        0        0
mm_stat (jobs3): 2147483648 16252928 25178112        0 25178112        0        0
mm_stat (jobs4): 2147483648 16252928 25178112        0 25178112        0        0
mm_stat (jobs5): 2147483648 16252928 25178112        0 25178112        0        0
mm_stat (jobs6): 2147483648 16252928 25178112        0 25178112        0        0
mm_stat (jobs7): 2147483648 16252928 25178112        0 25190400        0        0
mm_stat (jobs8): 2147483648 16252928 25178112        0 25190400        0        0
mm_stat (jobs9): 2147483648 16252928 25178112        0 25178112        0        0
mm_stat (jobs10): 2147483648 16252928 25178112        0 25178112        0        0

zram ZSTD mm_stat
mm_stat (jobs1): 2147483648 11010048 16781312        0 16781312        0        0
mm_stat (jobs2): 2147483648 11010048 16781312        0 16781312        0        0
mm_stat (jobs3): 2147483648 11010048 16781312        0 16785408        0        0
mm_stat (jobs4): 2147483648 11010048 16781312        0 16781312        0        0
mm_stat (jobs5): 2147483648 11010048 16781312        0 16781312        0        0
mm_stat (jobs6): 2147483648 11010048 16781312        0 16781312        0        0
mm_stat (jobs7): 2147483648 11010048 16781312        0 16781312        0        0
mm_stat (jobs8): 2147483648 11010048 16781312        0 16781312        0        0
mm_stat (jobs9): 2147483648 11010048 16781312        0 16785408        0        0
mm_stat (jobs10): 2147483648 11010048 16781312        0 16781312        0        0

==================================================================================

Official benchmarks [1]:

Compressor name         Ratio   Compression     Decompress.
zstd 1.1.3 -1           2.877   430 MB/s        1110 MB/s
zlib 1.2.8 -1           2.743   110 MB/s        400 MB/s
brotli 0.5.2 -0         2.708   400 MB/s        430 MB/s
quicklz 1.5.0 -1        2.238   550 MB/s        710 MB/s
lzo1x 2.09 -1           2.108   650 MB/s        830 MB/s
lz4 1.7.5               2.101   720 MB/s        3600 MB/s
snappy 1.1.3            2.091   500 MB/s        1650 MB/s
lzf 3.6 -1              2.077   400 MB/s        860 MB/s

Minchan said:

: I did test with my sample data and compared zstd with deflate.  zstd's
: compress ratio is lower a little bit but compression speed is much faster
: 3 times more and decompress speed is too 2 times more.  With different
: data, it is different but overall, zstd would be better for speed at the
: cost of a little lower compress ratio(about 5%) so I believe it's worth to
: replace deflate.

[1] https://github.com/facebook/zstd

Link: http://lkml.kernel.org/r/20170912050005.3247-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Acked-by: Minchan Kim &lt;minchan@kernel.org&gt;
Tested-by: Minchan Kim &lt;minchan@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add ZSTD to the list of supported compression algorithms.

ZRAM fio perf test:

                      LZO         DEFLATE         ZSTD

#jobs1
WRITE:              (2180MB/s)   (77.2MB/s)      (1429MB/s)
WRITE:              (1617MB/s)   (77.7MB/s)      (1202MB/s)
READ:                (426MB/s)   (595MB/s)       (1181MB/s)
READ:                (422MB/s)   (572MB/s)       (1020MB/s)
READ:                (318MB/s)   (67.8MB/s)      (563MB/s)
WRITE:               (318MB/s)   (67.9MB/s)      (564MB/s)
READ:                (336MB/s)   (68.3MB/s)      (583MB/s)
WRITE:               (335MB/s)   (68.2MB/s)      (582MB/s)
#jobs2
WRITE:              (3441MB/s)   (152MB/s)       (2141MB/s)
WRITE:              (2507MB/s)   (147MB/s)       (1888MB/s)
READ:                (801MB/s)   (1146MB/s)      (1890MB/s)
READ:                (767MB/s)   (1096MB/s)      (2073MB/s)
READ:                (621MB/s)   (126MB/s)       (1009MB/s)
WRITE:               (621MB/s)   (126MB/s)       (1009MB/s)
READ:                (656MB/s)   (125MB/s)       (1075MB/s)
WRITE:               (657MB/s)   (126MB/s)       (1077MB/s)
#jobs3
WRITE:              (4772MB/s)   (225MB/s)       (3394MB/s)
WRITE:              (3905MB/s)   (211MB/s)       (2939MB/s)
READ:               (1216MB/s)   (1608MB/s)      (3218MB/s)
READ:               (1159MB/s)   (1431MB/s)      (2981MB/s)
READ:                (906MB/s)   (156MB/s)       (1457MB/s)
WRITE:               (907MB/s)   (156MB/s)       (1458MB/s)
READ:                (953MB/s)   (158MB/s)       (1595MB/s)
WRITE:               (952MB/s)   (157MB/s)       (1593MB/s)
#jobs4
WRITE:              (6036MB/s)   (265MB/s)       (4469MB/s)
WRITE:              (5059MB/s)   (263MB/s)       (3951MB/s)
READ:               (1618MB/s)   (2066MB/s)      (4276MB/s)
READ:               (1573MB/s)   (1942MB/s)      (3830MB/s)
READ:               (1202MB/s)   (227MB/s)       (1971MB/s)
WRITE:              (1200MB/s)   (227MB/s)       (1968MB/s)
READ:               (1265MB/s)   (226MB/s)       (2116MB/s)
WRITE:              (1264MB/s)   (226MB/s)       (2114MB/s)
#jobs5
WRITE:              (5339MB/s)   (233MB/s)       (3781MB/s)
WRITE:              (4298MB/s)   (234MB/s)       (3276MB/s)
READ:               (1626MB/s)   (2048MB/s)      (4081MB/s)
READ:               (1567MB/s)   (1929MB/s)      (3758MB/s)
READ:               (1174MB/s)   (205MB/s)       (1747MB/s)
WRITE:              (1173MB/s)   (204MB/s)       (1746MB/s)
READ:               (1214MB/s)   (208MB/s)       (1890MB/s)
WRITE:              (1215MB/s)   (208MB/s)       (1892MB/s)
#jobs6
WRITE:              (5666MB/s)   (270MB/s)       (4338MB/s)
WRITE:              (4828MB/s)   (267MB/s)       (3772MB/s)
READ:               (1803MB/s)   (2058MB/s)      (4946MB/s)
READ:               (1805MB/s)   (2156MB/s)      (4711MB/s)
READ:               (1334MB/s)   (235MB/s)       (2135MB/s)
WRITE:              (1335MB/s)   (235MB/s)       (2137MB/s)
READ:               (1364MB/s)   (236MB/s)       (2268MB/s)
WRITE:              (1365MB/s)   (237MB/s)       (2270MB/s)
#jobs7
WRITE:              (5474MB/s)   (270MB/s)       (4300MB/s)
WRITE:              (4666MB/s)   (266MB/s)       (3817MB/s)
READ:               (2022MB/s)   (2319MB/s)      (5472MB/s)
READ:               (1924MB/s)   (2260MB/s)      (5031MB/s)
READ:               (1369MB/s)   (242MB/s)       (2153MB/s)
WRITE:              (1370MB/s)   (242MB/s)       (2155MB/s)
READ:               (1499MB/s)   (246MB/s)       (2310MB/s)
WRITE:              (1497MB/s)   (246MB/s)       (2307MB/s)
#jobs8
WRITE:              (5558MB/s)   (273MB/s)       (4439MB/s)
WRITE:              (4763MB/s)   (271MB/s)       (3918MB/s)
READ:               (2201MB/s)   (2599MB/s)      (6062MB/s)
READ:               (2105MB/s)   (2463MB/s)      (5413MB/s)
READ:               (1490MB/s)   (252MB/s)       (2238MB/s)
WRITE:              (1488MB/s)   (252MB/s)       (2236MB/s)
READ:               (1566MB/s)   (254MB/s)       (2434MB/s)
WRITE:              (1568MB/s)   (254MB/s)       (2437MB/s)
#jobs9
WRITE:              (5120MB/s)   (264MB/s)       (4035MB/s)
WRITE:              (4531MB/s)   (267MB/s)       (3740MB/s)
READ:               (1940MB/s)   (2258MB/s)      (4986MB/s)
READ:               (2024MB/s)   (2387MB/s)      (4871MB/s)
READ:               (1343MB/s)   (246MB/s)       (2038MB/s)
WRITE:              (1342MB/s)   (246MB/s)       (2037MB/s)
READ:               (1553MB/s)   (238MB/s)       (2243MB/s)
WRITE:              (1552MB/s)   (238MB/s)       (2242MB/s)
#jobs10
WRITE:              (5345MB/s)   (271MB/s)       (3988MB/s)
WRITE:              (4750MB/s)   (254MB/s)       (3668MB/s)
READ:               (1876MB/s)   (2363MB/s)      (5150MB/s)
READ:               (1990MB/s)   (2256MB/s)      (5080MB/s)
READ:               (1355MB/s)   (250MB/s)       (2019MB/s)
WRITE:              (1356MB/s)   (251MB/s)       (2020MB/s)
READ:               (1490MB/s)   (252MB/s)       (2202MB/s)
WRITE:              (1488MB/s)   (252MB/s)       (2199MB/s)

jobs1                              perfstat
instructions                 52,065,555,710 (    0.79)    855,731,114,587 (    2.64)       54,280,709,944 (    1.40)
branches                     14,020,427,116 ( 725.847)    101,733,449,582 (1074.521)       11,170,591,067 ( 992.869)
branch-misses                    22,626,174 (   0.16%)        274,197,885 (   0.27%)           25,915,805 (   0.23%)
jobs2                              perfstat
instructions                103,633,110,402 (    0.75)  1,710,822,100,914 (    2.59)      107,879,874,104 (    1.28)
branches                     27,931,237,282 ( 679.203)    203,298,267,479 (1037.326)       22,185,350,842 ( 884.427)
branch-misses                    46,103,811 (   0.17%)        533,747,204 (   0.26%)           49,682,483 (   0.22%)
jobs3                              perfstat
instructions                154,857,283,657 (    0.76)  2,565,748,974,197 (    2.57)      161,515,435,813 (    1.31)
branches                     41,759,490,355 ( 670.529)    304,905,605,277 ( 978.765)       33,215,805,907 ( 888.003)
branch-misses                    74,263,293 (   0.18%)        759,746,240 (   0.25%)           76,841,196 (   0.23%)
jobs4                              perfstat
instructions                206,215,849,076 (    0.75)  3,420,169,460,897 (    2.60)      215,003,061,664 (    1.31)
branches                     55,632,141,739 ( 666.501)    406,394,977,433 ( 927.241)       44,214,322,251 ( 883.532)
branch-misses                   102,287,788 (   0.18%)      1,098,617,314 (   0.27%)          103,891,040 (   0.23%)
jobs5                              perfstat
instructions                258,711,315,588 (    0.67)  4,275,657,533,244 (    2.23)      269,332,235,685 (    1.08)
branches                     69,802,821,166 ( 588.823)    507,996,211,252 ( 797.036)       55,450,846,129 ( 735.095)
branch-misses                   129,217,214 (   0.19%)      1,243,284,991 (   0.24%)          173,512,278 (   0.31%)
jobs6                              perfstat
instructions                312,796,166,008 (    0.61)  5,133,896,344,660 (    2.02)      323,658,769,588 (    1.04)
branches                     84,372,488,583 ( 520.541)    610,310,494,402 ( 697.642)       66,683,292,992 ( 693.939)
branch-misses                   159,438,978 (   0.19%)      1,396,368,563 (   0.23%)          174,406,934 (   0.26%)
jobs7                              perfstat
instructions                363,211,372,930 (    0.56)  5,988,205,600,879 (    1.75)      377,824,674,156 (    0.93)
branches                     98,057,013,765 ( 463.117)    711,841,255,974 ( 598.762)       77,879,009,954 ( 600.443)
branch-misses                   199,513,153 (   0.20%)      1,507,651,077 (   0.21%)          248,203,369 (   0.32%)
jobs8                              perfstat
instructions                413,960,354,615 (    0.52)  6,842,918,558,378 (    1.45)      431,938,486,581 (    0.83)
branches                    111,812,574,884 ( 414.224)    813,299,084,518 ( 491.173)       89,062,699,827 ( 517.795)
branch-misses                   233,584,845 (   0.21%)      1,531,593,921 (   0.19%)          286,818,489 (   0.32%)
jobs9                              perfstat
instructions                465,976,220,300 (    0.53)  7,698,467,237,372 (    1.47)      486,352,600,321 (    0.84)
branches                    125,931,456,162 ( 424.063)    915,207,005,715 ( 498.192)      100,370,404,090 ( 517.439)
branch-misses                   256,992,445 (   0.20%)      1,782,809,816 (   0.19%)          345,239,380 (   0.34%)
jobs10                             perfstat
instructions                517,406,372,715 (    0.53)  8,553,527,312,900 (    1.48)      540,732,653,094 (    0.84)
branches                    139,839,780,676 ( 427.732)  1,016,737,699,389 ( 503.172)      111,696,557,638 ( 516.750)
branch-misses                   259,595,561 (   0.19%)      1,952,570,279 (   0.19%)          357,818,661 (   0.32%)

seconds elapsed        20.630411534     96.084546565    12.743373571
seconds elapsed        22.292627625     100.984155001   14.407413560
seconds elapsed        22.396016966     110.344880848   14.032201392
seconds elapsed        22.517330949     113.351459170   14.243074935
seconds elapsed        28.548305104     156.515193765   19.159286861
seconds elapsed        30.453538116     164.559937678   19.362492717
seconds elapsed        33.467108086     188.486827481   21.492612173
seconds elapsed        35.617727591     209.602677783   23.256422492
seconds elapsed        42.584239509     243.959902566   28.458540338
seconds elapsed        47.683632526     269.635248851   31.542404137

Over all, ZSTD has slower WRITE, but much faster READ (perhaps
a static compression buffer used during the test helped ZSTD a
lot), which results in faster test results.

Memory consumption (zram mm_stat file):

zram LZO mm_stat
mm_stat (jobs1): 2147483648 23068672 33558528        0 33558528        0        0
mm_stat (jobs2): 2147483648 23068672 33558528        0 33558528        0        0
mm_stat (jobs3): 2147483648 23068672 33558528        0 33562624        0        0
mm_stat (jobs4): 2147483648 23068672 33558528        0 33558528        0        0
mm_stat (jobs5): 2147483648 23068672 33558528        0 33558528        0        0
mm_stat (jobs6): 2147483648 23068672 33558528        0 33562624        0        0
mm_stat (jobs7): 2147483648 23068672 33558528        0 33566720        0        0
mm_stat (jobs8): 2147483648 23068672 33558528        0 33558528        0        0
mm_stat (jobs9): 2147483648 23068672 33558528        0 33558528        0        0
mm_stat (jobs10): 2147483648 23068672 33558528        0 33562624        0        0

zram DEFLATE mm_stat
mm_stat (jobs1): 2147483648 16252928 25178112        0 25178112        0        0
mm_stat (jobs2): 2147483648 16252928 25178112        0 25178112        0        0
mm_stat (jobs3): 2147483648 16252928 25178112        0 25178112        0        0
mm_stat (jobs4): 2147483648 16252928 25178112        0 25178112        0        0
mm_stat (jobs5): 2147483648 16252928 25178112        0 25178112        0        0
mm_stat (jobs6): 2147483648 16252928 25178112        0 25178112        0        0
mm_stat (jobs7): 2147483648 16252928 25178112        0 25190400        0        0
mm_stat (jobs8): 2147483648 16252928 25178112        0 25190400        0        0
mm_stat (jobs9): 2147483648 16252928 25178112        0 25178112        0        0
mm_stat (jobs10): 2147483648 16252928 25178112        0 25178112        0        0

zram ZSTD mm_stat
mm_stat (jobs1): 2147483648 11010048 16781312        0 16781312        0        0
mm_stat (jobs2): 2147483648 11010048 16781312        0 16781312        0        0
mm_stat (jobs3): 2147483648 11010048 16781312        0 16785408        0        0
mm_stat (jobs4): 2147483648 11010048 16781312        0 16781312        0        0
mm_stat (jobs5): 2147483648 11010048 16781312        0 16781312        0        0
mm_stat (jobs6): 2147483648 11010048 16781312        0 16781312        0        0
mm_stat (jobs7): 2147483648 11010048 16781312        0 16781312        0        0
mm_stat (jobs8): 2147483648 11010048 16781312        0 16781312        0        0
mm_stat (jobs9): 2147483648 11010048 16781312        0 16785408        0        0
mm_stat (jobs10): 2147483648 11010048 16781312        0 16781312        0        0

==================================================================================

Official benchmarks [1]:

Compressor name         Ratio   Compression     Decompress.
zstd 1.1.3 -1           2.877   430 MB/s        1110 MB/s
zlib 1.2.8 -1           2.743   110 MB/s        400 MB/s
brotli 0.5.2 -0         2.708   400 MB/s        430 MB/s
quicklz 1.5.0 -1        2.238   550 MB/s        710 MB/s
lzo1x 2.09 -1           2.108   650 MB/s        830 MB/s
lz4 1.7.5               2.101   720 MB/s        3600 MB/s
snappy 1.1.3            2.091   500 MB/s        1650 MB/s
lzf 3.6 -1              2.077   400 MB/s        860 MB/s

Minchan said:

: I did test with my sample data and compared zstd with deflate.  zstd's
: compress ratio is lower a little bit but compression speed is much faster
: 3 times more and decompress speed is too 2 times more.  With different
: data, it is different but overall, zstd would be better for speed at the
: cost of a little lower compress ratio(about 5%) so I believe it's worth to
: replace deflate.

[1] https://github.com/facebook/zstd

Link: http://lkml.kernel.org/r/20170912050005.3247-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Acked-by: Minchan Kim &lt;minchan@kernel.org&gt;
Tested-by: Minchan Kim &lt;minchan@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bdi: introduce BDI_CAP_SYNCHRONOUS_IO</title>
<updated>2017-11-16T02:21:02+00:00</updated>
<author>
<name>Minchan Kim</name>
<email>minchan@kernel.org</email>
</author>
<published>2017-11-16T01:33:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=23c47d2ada9f96731492a67b28c0072715075baa'/>
<id>23c47d2ada9f96731492a67b28c0072715075baa</id>
<content type='text'>
As discussed at

  https://lkml.kernel.org/r/&lt;20170728165604.10455-1-ross.zwisler@linux.intel.com&gt;

someday we will remove rw_page().  If so, we need something to detect
such super-fast storage on which synchronous IO operations like the
current rw_page are always a win.

Introduces BDI_CAP_SYNCHRONOUS_IO to indicate such devices.  With it, we
could use various optimization techniques.

Link: http://lkml.kernel.org/r/1505886205-9671-3-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: Ross Zwisler &lt;ross.zwisler@linux.intel.com&gt;
Cc: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Ilya Dryomov &lt;idryomov@gmail.com&gt;
Cc: Jens Axboe &lt;axboe@kernel.dk&gt;
Cc: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Cc: Huang Ying &lt;ying.huang@intel.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
As discussed at

  https://lkml.kernel.org/r/&lt;20170728165604.10455-1-ross.zwisler@linux.intel.com&gt;

someday we will remove rw_page().  If so, we need something to detect
such super-fast storage on which synchronous IO operations like the
current rw_page are always a win.

Introduces BDI_CAP_SYNCHRONOUS_IO to indicate such devices.  With it, we
could use various optimization techniques.

Link: http://lkml.kernel.org/r/1505886205-9671-3-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: Ross Zwisler &lt;ross.zwisler@linux.intel.com&gt;
Cc: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Ilya Dryomov &lt;idryomov@gmail.com&gt;
Cc: Jens Axboe &lt;axboe@kernel.dk&gt;
Cc: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Cc: Huang Ying &lt;ying.huang@intel.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>zram: set BDI_CAP_STABLE_WRITES once</title>
<updated>2017-11-16T02:21:02+00:00</updated>
<author>
<name>Minchan Kim</name>
<email>minchan@kernel.org</email>
</author>
<published>2017-11-16T01:32:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=e447a0151f7ce8dd884fea48279274bd64434c29'/>
<id>e447a0151f7ce8dd884fea48279274bd64434c29</id>
<content type='text'>
With fast swap storage, the platform wants to use swap more aggressively
and swap-in is crucial to application latency.

The rw_page() based synchronous devices like zram, pmem and btt are such
fast storage.  When I profile swapin performance with zram lz4
decompress test, S/W overhead is more than 70%.  Maybe, it would be
bigger in nvdimm.

This patchset reduces swap-in latency by skipping swapcache if the swap
device is a synchronous device like a rw_page() based device.

It enhances by 45% my swapin test (5G sequential swapin, no readahead)
from 2.41sec to 1.64sec.

This patch (of 4):

Commit 19b7ccf8651d ("block: get rid of blk_integrity_revalidate()")
fixed a weird thing (i.e., reset BDI_CAP_STABLE_WRITES flag
unconditionally whenever revalidat_disk is called) so zram doesn't need
to reset the flag any more when revalidating the bdev.  Instead, set the
flag just once when the zram device is created.

It shouldn't change any behavior.

Link: http://lkml.kernel.org/r/1505886205-9671-2-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim &lt;minchan@kernel.org&gt;
Reviewed-by: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Cc: Ilya Dryomov &lt;idryomov@gmail.com&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: Ross Zwisler &lt;ross.zwisler@linux.intel.com&gt;
Cc: Jens Axboe &lt;axboe@kernel.dk&gt;
Cc: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Huang Ying &lt;ying.huang@intel.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
With fast swap storage, the platform wants to use swap more aggressively
and swap-in is crucial to application latency.

The rw_page() based synchronous devices like zram, pmem and btt are such
fast storage.  When I profile swapin performance with zram lz4
decompress test, S/W overhead is more than 70%.  Maybe, it would be
bigger in nvdimm.

This patchset reduces swap-in latency by skipping swapcache if the swap
device is a synchronous device like a rw_page() based device.

It enhances by 45% my swapin test (5G sequential swapin, no readahead)
from 2.41sec to 1.64sec.

This patch (of 4):

Commit 19b7ccf8651d ("block: get rid of blk_integrity_revalidate()")
fixed a weird thing (i.e., reset BDI_CAP_STABLE_WRITES flag
unconditionally whenever revalidat_disk is called) so zram doesn't need
to reset the flag any more when revalidating the bdev.  Instead, set the
flag just once when the zram device is created.

It shouldn't change any behavior.

Link: http://lkml.kernel.org/r/1505886205-9671-2-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim &lt;minchan@kernel.org&gt;
Reviewed-by: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Cc: Ilya Dryomov &lt;idryomov@gmail.com&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: Ross Zwisler &lt;ross.zwisler@linux.intel.com&gt;
Cc: Jens Axboe &lt;axboe@kernel.dk&gt;
Cc: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Huang Ying &lt;ying.huang@intel.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>License cleanup: add SPDX GPL-2.0 license identifier to files with no license</title>
<updated>2017-11-02T10:10:55+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2017-11-01T14:07:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b24413180f5600bcb3bb70fbed5cf186b60864bd'/>
<id>b24413180f5600bcb3bb70fbed5cf186b60864bd</id>
<content type='text'>
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode &amp; Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained &gt;5
   lines of source
 - File already had some variant of a license header in it (even if &lt;5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart &lt;kstewart@linuxfoundation.org&gt;
Reviewed-by: Philippe Ombredanne &lt;pombredanne@nexb.com&gt;
Reviewed-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode &amp; Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained &gt;5
   lines of source
 - File already had some variant of a license header in it (even if &lt;5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart &lt;kstewart@linuxfoundation.org&gt;
Reviewed-by: Philippe Ombredanne &lt;pombredanne@nexb.com&gt;
Reviewed-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>zram: fix null dereference of handle</title>
<updated>2017-10-04T00:54:24+00:00</updated>
<author>
<name>Minchan Kim</name>
<email>minchan@kernel.org</email>
</author>
<published>2017-10-03T23:15:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ae94264ed4b0cf7cd887947650db4c69acb62072'/>
<id>ae94264ed4b0cf7cd887947650db4c69acb62072</id>
<content type='text'>
In testing I found handle passed to zs_map_object in __zram_bvec_read is
NULL so eh kernel goes oops in pin_object().

The reason is there is no routine to check the slot's freeing after
getting the slot's lock.  This patch fixes it.

[minchan@kernel.org: v2]
  Link: http://lkml.kernel.org/r/1505887347-10881-1-git-send-email-minchan@kernel.org
Link: http://lkml.kernel.org/r/1505788488-26723-1-git-send-email-minchan@kernel.org
Fixes: 1f7319c74275 ("zram: partial IO refactoring")
Signed-off-by: Minchan Kim &lt;minchan@kernel.org&gt;
Reviewed-by: Sergey Senozhatsky &lt;sergey.senozhatsky.work@gmail.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In testing I found handle passed to zs_map_object in __zram_bvec_read is
NULL so eh kernel goes oops in pin_object().

The reason is there is no routine to check the slot's freeing after
getting the slot's lock.  This patch fixes it.

[minchan@kernel.org: v2]
  Link: http://lkml.kernel.org/r/1505887347-10881-1-git-send-email-minchan@kernel.org
Link: http://lkml.kernel.org/r/1505788488-26723-1-git-send-email-minchan@kernel.org
Fixes: 1f7319c74275 ("zram: partial IO refactoring")
Signed-off-by: Minchan Kim &lt;minchan@kernel.org&gt;
Reviewed-by: Sergey Senozhatsky &lt;sergey.senozhatsky.work@gmail.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drivers/block/zram/zram_drv.c: convert to using memset_l</title>
<updated>2017-09-09T01:26:48+00:00</updated>
<author>
<name>Matthew Wilcox</name>
<email>mawilcox@microsoft.com</email>
</author>
<published>2017-09-08T23:14:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=48ad1abef40226ce809e5b7d3a5898754c4b9a9a'/>
<id>48ad1abef40226ce809e5b7d3a5898754c4b9a9a</id>
<content type='text'>
zram was the motivation for creating memset_l().  Minchan Kim sees a 7%
performance improvement on x86 with 100MB of non-zero deduplicatable
data:

        perf stat -r 10 dd if=/dev/zram0 of=/dev/null

vanilla:        0.232050465 seconds time elapsed ( +-  0.51% )
memset_l:	0.217219387 seconds time elapsed ( +-  0.07% )

Link: http://lkml.kernel.org/r/20170720184539.31609-7-willy@infradead.org
Signed-off-by: Matthew Wilcox &lt;mawilcox@microsoft.com&gt;
Tested-by: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: "James E.J. Bottomley" &lt;jejb@linux.vnet.ibm.com&gt;
Cc: "Martin K. Petersen" &lt;martin.petersen@oracle.com&gt;
Cc: David Miller &lt;davem@davemloft.net&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Ivan Kokshaysky &lt;ink@jurassic.park.msu.ru&gt;
Cc: Matt Turner &lt;mattst88@gmail.com&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: Richard Henderson &lt;rth@twiddle.net&gt;
Cc: Russell King &lt;rmk+kernel@armlinux.org.uk&gt;
Cc: Sam Ravnborg &lt;sam@ravnborg.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
zram was the motivation for creating memset_l().  Minchan Kim sees a 7%
performance improvement on x86 with 100MB of non-zero deduplicatable
data:

        perf stat -r 10 dd if=/dev/zram0 of=/dev/null

vanilla:        0.232050465 seconds time elapsed ( +-  0.51% )
memset_l:	0.217219387 seconds time elapsed ( +-  0.07% )

Link: http://lkml.kernel.org/r/20170720184539.31609-7-willy@infradead.org
Signed-off-by: Matthew Wilcox &lt;mawilcox@microsoft.com&gt;
Tested-by: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Sergey Senozhatsky &lt;sergey.senozhatsky@gmail.com&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: "James E.J. Bottomley" &lt;jejb@linux.vnet.ibm.com&gt;
Cc: "Martin K. Petersen" &lt;martin.petersen@oracle.com&gt;
Cc: David Miller &lt;davem@davemloft.net&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Ivan Kokshaysky &lt;ink@jurassic.park.msu.ru&gt;
Cc: Matt Turner &lt;mattst88@gmail.com&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: Richard Henderson &lt;rth@twiddle.net&gt;
Cc: Russell King &lt;rmk+kernel@armlinux.org.uk&gt;
Cc: Sam Ravnborg &lt;sam@ravnborg.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'for-4.14/block' of git://git.kernel.dk/linux-block</title>
<updated>2017-09-07T18:59:42+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2017-09-07T18:59:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a0725ab0c7536076d5477264420ef420ebb64501'/>
<id>a0725ab0c7536076d5477264420ef420ebb64501</id>
<content type='text'>
Pull block layer updates from Jens Axboe:
 "This is the first pull request for 4.14, containing most of the code
  changes. It's a quiet series this round, which I think we needed after
  the churn of the last few series. This contains:

   - Fix for a registration race in loop, from Anton Volkov.

   - Overflow complaint fix from Arnd for DAC960.

   - Series of drbd changes from the usual suspects.

   - Conversion of the stec/skd driver to blk-mq. From Bart.

   - A few BFQ improvements/fixes from Paolo.

   - CFQ improvement from Ritesh, allowing idling for group idle.

   - A few fixes found by Dan's smatch, courtesy of Dan.

   - A warning fixup for a race between changing the IO scheduler and
     device remova. From David Jeffery.

   - A few nbd fixes from Josef.

   - Support for cgroup info in blktrace, from Shaohua.

   - Also from Shaohua, new features in the null_blk driver to allow it
     to actually hold data, among other things.

   - Various corner cases and error handling fixes from Weiping Zhang.

   - Improvements to the IO stats tracking for blk-mq from me. Can
     drastically improve performance for fast devices and/or big
     machines.

   - Series from Christoph removing bi_bdev as being needed for IO
     submission, in preparation for nvme multipathing code.

   - Series from Bart, including various cleanups and fixes for switch
     fall through case complaints"

* 'for-4.14/block' of git://git.kernel.dk/linux-block: (162 commits)
  kernfs: checking for IS_ERR() instead of NULL
  drbd: remove BIOSET_NEED_RESCUER flag from drbd_{md_,}io_bio_set
  drbd: Fix allyesconfig build, fix recent commit
  drbd: switch from kmalloc() to kmalloc_array()
  drbd: abort drbd_start_resync if there is no connection
  drbd: move global variables to drbd namespace and make some static
  drbd: rename "usermode_helper" to "drbd_usermode_helper"
  drbd: fix race between handshake and admin disconnect/down
  drbd: fix potential deadlock when trying to detach during handshake
  drbd: A single dot should be put into a sequence.
  drbd: fix rmmod cleanup, remove _all_ debugfs entries
  drbd: Use setup_timer() instead of init_timer() to simplify the code.
  drbd: fix potential get_ldev/put_ldev refcount imbalance during attach
  drbd: new disk-option disable-write-same
  drbd: Fix resource role for newly created resources in events2
  drbd: mark symbols static where possible
  drbd: Send P_NEG_ACK upon write error in protocol != C
  drbd: add explicit plugging when submitting batches
  drbd: change list_for_each_safe to while(list_first_entry_or_null)
  drbd: introduce drbd_recv_header_maybe_unplug
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull block layer updates from Jens Axboe:
 "This is the first pull request for 4.14, containing most of the code
  changes. It's a quiet series this round, which I think we needed after
  the churn of the last few series. This contains:

   - Fix for a registration race in loop, from Anton Volkov.

   - Overflow complaint fix from Arnd for DAC960.

   - Series of drbd changes from the usual suspects.

   - Conversion of the stec/skd driver to blk-mq. From Bart.

   - A few BFQ improvements/fixes from Paolo.

   - CFQ improvement from Ritesh, allowing idling for group idle.

   - A few fixes found by Dan's smatch, courtesy of Dan.

   - A warning fixup for a race between changing the IO scheduler and
     device remova. From David Jeffery.

   - A few nbd fixes from Josef.

   - Support for cgroup info in blktrace, from Shaohua.

   - Also from Shaohua, new features in the null_blk driver to allow it
     to actually hold data, among other things.

   - Various corner cases and error handling fixes from Weiping Zhang.

   - Improvements to the IO stats tracking for blk-mq from me. Can
     drastically improve performance for fast devices and/or big
     machines.

   - Series from Christoph removing bi_bdev as being needed for IO
     submission, in preparation for nvme multipathing code.

   - Series from Bart, including various cleanups and fixes for switch
     fall through case complaints"

* 'for-4.14/block' of git://git.kernel.dk/linux-block: (162 commits)
  kernfs: checking for IS_ERR() instead of NULL
  drbd: remove BIOSET_NEED_RESCUER flag from drbd_{md_,}io_bio_set
  drbd: Fix allyesconfig build, fix recent commit
  drbd: switch from kmalloc() to kmalloc_array()
  drbd: abort drbd_start_resync if there is no connection
  drbd: move global variables to drbd namespace and make some static
  drbd: rename "usermode_helper" to "drbd_usermode_helper"
  drbd: fix race between handshake and admin disconnect/down
  drbd: fix potential deadlock when trying to detach during handshake
  drbd: A single dot should be put into a sequence.
  drbd: fix rmmod cleanup, remove _all_ debugfs entries
  drbd: Use setup_timer() instead of init_timer() to simplify the code.
  drbd: fix potential get_ldev/put_ldev refcount imbalance during attach
  drbd: new disk-option disable-write-same
  drbd: Fix resource role for newly created resources in events2
  drbd: mark symbols static where possible
  drbd: Send P_NEG_ACK upon write error in protocol != C
  drbd: add explicit plugging when submitting batches
  drbd: change list_for_each_safe to while(list_first_entry_or_null)
  drbd: introduce drbd_recv_header_maybe_unplug
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>block, THP: make block_device_operations.rw_page support THP</title>
<updated>2017-09-07T00:27:27+00:00</updated>
<author>
<name>Huang Ying</name>
<email>ying.huang@intel.com</email>
</author>
<published>2017-09-06T23:22:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=98cc093cba1e925eb34963dedb5f1684f1bdb2f4'/>
<id>98cc093cba1e925eb34963dedb5f1684f1bdb2f4</id>
<content type='text'>
The .rw_page in struct block_device_operations is used by the swap
subsystem to read/write the page contents from/into the corresponding
swap slot in the swap device.  To support the THP (Transparent Huge
Page) swap optimization, the .rw_page is enhanced to support to
read/write THP if possible.

Link: http://lkml.kernel.org/r/20170724051840.2309-6-ying.huang@intel.com
Signed-off-by: "Huang, Ying" &lt;ying.huang@intel.com&gt;
Reviewed-by: Ross Zwisler &lt;ross.zwisler@intel.com&gt; [for brd.c, zram_drv.c, pmem.c]
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: Vishal L Verma &lt;vishal.l.verma@intel.com&gt;
Cc: Jens Axboe &lt;axboe@kernel.dk&gt;
Cc: "Kirill A . Shutemov" &lt;kirill.shutemov@linux.intel.com&gt;
Cc: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Cc: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Rik van Riel &lt;riel@redhat.com&gt;
Cc: Shaohua Li &lt;shli@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
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The .rw_page in struct block_device_operations is used by the swap
subsystem to read/write the page contents from/into the corresponding
swap slot in the swap device.  To support the THP (Transparent Huge
Page) swap optimization, the .rw_page is enhanced to support to
read/write THP if possible.

Link: http://lkml.kernel.org/r/20170724051840.2309-6-ying.huang@intel.com
Signed-off-by: "Huang, Ying" &lt;ying.huang@intel.com&gt;
Reviewed-by: Ross Zwisler &lt;ross.zwisler@intel.com&gt; [for brd.c, zram_drv.c, pmem.c]
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: Vishal L Verma &lt;vishal.l.verma@intel.com&gt;
Cc: Jens Axboe &lt;axboe@kernel.dk&gt;
Cc: "Kirill A . Shutemov" &lt;kirill.shutemov@linux.intel.com&gt;
Cc: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Cc: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Rik van Riel &lt;riel@redhat.com&gt;
Cc: Shaohua Li &lt;shli@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
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