https://github.com/torvalds/linux
- HEAD
- refs/heads/arm64-uaccess
- refs/heads/dependabot/pip/drivers/gpu/drm/ci/xfails/certifi-2024.7.4
- refs/heads/dependabot/pip/drivers/gpu/drm/ci/xfails/idna-3.7
- refs/heads/dependabot/pip/drivers/gpu/drm/ci/xfails/requests-2.32.2
- refs/heads/dependabot/pip/drivers/gpu/drm/ci/xfails/setuptools-70.0.0
- refs/heads/dependabot/pip/drivers/gpu/drm/ci/xfails/urllib3-2.2.2
- refs/heads/master
- v6.9-rc7
- v6.9-rc6
- v6.9-rc5
- v6.9-rc4
- v6.9-rc3
- v6.9-rc2
- v6.9-rc1
- v6.9
- v6.8-rc7
- v6.8-rc6
- v6.8-rc5
- v6.8-rc4
- v6.8-rc3
- v6.8-rc2
- v6.8-rc1
- v6.8
- v6.7-rc8
- v6.7-rc7
- v6.7-rc6
- v6.7-rc5
- v6.7-rc4
- v6.7-rc3
- v6.7-rc2
- v6.7-rc1
- v6.7
- v6.6-rc7
- v6.6-rc6
- v6.6-rc5
- v6.6-rc4
- v6.6-rc3
- v6.6-rc2
- v6.6-rc1
- v6.6
- v6.5-rc7
- v6.5-rc6
- v6.5-rc5
- v6.5-rc4
- v6.5-rc3
- v6.5-rc2
- v6.5-rc1
- v6.5
- v6.4-rc7
- v6.4-rc6
- v6.4-rc5
- v6.4-rc4
- v6.4-rc3
- v6.4-rc2
- v6.4-rc1
- v6.4
- v6.3-rc7
- v6.3-rc6
- v6.3-rc5
- v6.3-rc4
- v6.3-rc3
- v6.3-rc2
- v6.3-rc1
- v6.3
- v6.2-rc8
- v6.2-rc7
- v6.2-rc6
- v6.2-rc5
- v6.2-rc4
- v6.2-rc3
- v6.2-rc2
- v6.2-rc1
- v6.2
- v6.11-rc3
- v6.11-rc2
- v6.11-rc1
- v6.10-rc7
- v6.10-rc6
- v6.10-rc5
- v6.10-rc4
- v6.10-rc3
- v6.10-rc2
- v6.10-rc1
- v6.10
- v6.1-rc8
- v6.1-rc7
- v6.1-rc6
- v6.1-rc5
- v6.1-rc4
- v6.1-rc3
- v6.1-rc2
- v6.1-rc1
- v6.1
- v6.0-rc7
- v6.0-rc6
- v6.0-rc5
- v6.0-rc4
- v6.0-rc3
- v6.0-rc2
- v6.0-rc1
- v6.0
- v5.9-rc8
- v5.9-rc7
- v5.9-rc6
- v5.9-rc5
- v5.9-rc4
- v5.9-rc3
- v5.9-rc2
- v5.9-rc1
- v5.9
- v5.8-rc7
- v5.8-rc6
- v5.8-rc5
- v5.8-rc4
- v5.8-rc3
- v5.8-rc2
- v5.8-rc1
- v5.8
- v5.7-rc7
- v5.7-rc6
- v5.7-rc5
- v5.7-rc4
- v5.7-rc3
- v5.7-rc2
- v5.7-rc1
- v5.7
- v5.6-rc7
- v5.6-rc6
- v5.6-rc5
- v5.6-rc4
- v5.6-rc3
- v5.6-rc2
- v5.6-rc1
- v5.6
- v5.5-rc7
- v5.5-rc6
- v5.5-rc5
- v5.5-rc4
- v5.5-rc3
- v5.5-rc2
- v5.5-rc1
- v5.5
- v5.4-rc8
- v5.4-rc7
- v5.4-rc6
- v5.4-rc5
- v5.4-rc4
- v5.4-rc3
- v5.4-rc2
- v5.4-rc1
- v5.4
- v5.3-rc8
- v5.3-rc7
- v5.3-rc6
- v5.3-rc5
- v5.3-rc4
- v5.3-rc3
- v5.3-rc2
- v5.3-rc1
- v5.3
- v5.2-rc7
- v5.2-rc6
- v5.2-rc5
- v5.2-rc4
- v5.2-rc3
- v5.2-rc2
- v5.2-rc1
- v5.2
- v5.19-rc8
- v5.19-rc7
- v5.19-rc6
- v5.19-rc5
- v5.19-rc4
- v5.19-rc3
- v5.19-rc2
- v5.19-rc1
- v5.19
- v5.18-rc7
- v5.18-rc6
- v5.18-rc5
- v5.18-rc4
- v5.18-rc3
- v5.18-rc2
- v5.18-rc1
- v5.18
- v5.17-rc8
- v5.17-rc7
- v5.17-rc6
- v5.17-rc5
- v5.17-rc4
- v5.17-rc3
- v5.17-rc2
- v5.17-rc1
- v5.17
- v5.16-rc8
- v5.16-rc7
- v5.16-rc6
- v5.16-rc5
- v5.16-rc4
- v5.16-rc3
- v5.16-rc2
- v5.16-rc1
- v5.16
- v5.15-rc7
- v5.15-rc6
- v5.15-rc5
- v5.15-rc4
- v5.15-rc3
- v5.15-rc2
- v5.15-rc1
- v5.15
- v5.14-rc7
- v5.14-rc6
- v5.14-rc5
- v5.14-rc4
- v5.14-rc3
- v5.14-rc2
- v5.14-rc1
- v5.14
- v5.13-rc7
- v5.13-rc6
- v5.13-rc5
- v5.13-rc4
- v5.13-rc3
- v5.13-rc2
- v5.13-rc1
- v5.13
- v5.12-rc8
- v5.12-rc7
- v5.12-rc6
- v5.12-rc5
- v5.12-rc4
- v5.12-rc3
- v5.12-rc2
- v5.12-rc1
- v5.12
- v5.11-rc7
- v5.11-rc6
- v5.11-rc5
- v5.11-rc4
- v5.11-rc3
- v5.11-rc2
- v5.11-rc1
- v5.11
- v5.10-rc7
- v5.10-rc6
- v5.10-rc5
- v5.10-rc4
- v5.10-rc3
- v5.10-rc2
- v5.10-rc1
- v5.10
- v5.1-rc7
- v5.1-rc6
- v5.1-rc5
- v5.1-rc4
- v5.1-rc3
- v5.1-rc2
- v5.1-rc1
- v5.1
- v5.0-rc8
- v5.0-rc7
- v5.0-rc6
- v5.0-rc5
- v5.0-rc4
- v5.0-rc3
- v5.0-rc2
- v5.0-rc1
- v5.0
- v4.9-rc8
- v4.9-rc7
- v4.9-rc6
- v4.9-rc5
- v4.9-rc4
- v4.9-rc3
- v4.9-rc2
- v4.9-rc1
- v4.9
- v4.8-rc8
- v4.8-rc7
- v4.8-rc6
- v4.8-rc5
- v4.8-rc4
- v4.8-rc3
- v4.8-rc2
- v4.8-rc1
- v4.8
- v4.7-rc7
- v4.7-rc6
- v4.7-rc5
- v4.7-rc4
- v4.7-rc3
- v4.7-rc2
- v4.7-rc1
- v4.7
- v4.6-rc7
- v4.6-rc6
- v4.6-rc5
- v4.6-rc4
- v4.6-rc3
- v4.6-rc2
- v4.6-rc1
- v4.6
- v4.5-rc7
- v4.5-rc6
- v4.5-rc5
- v4.5-rc4
- v4.5-rc3
- v4.5-rc2
- v4.5-rc1
- v4.5
- v4.4-rc8
- v4.4-rc7
- v4.4-rc6
- v4.4-rc5
- v4.4-rc4
- v4.4-rc3
- v4.4-rc2
- v4.4-rc1
- v4.4
- v4.3-rc7
- v4.3-rc6
- v4.3-rc5
- v4.3-rc4
- v4.3-rc3
- v4.3-rc2
- v4.3-rc1
- v4.3
- v4.20-rc7
- v4.20-rc6
- v4.20-rc5
- v4.20-rc4
- v4.20-rc3
- v4.20-rc2
- v4.20-rc1
- v4.20
- v4.2-rc8
- v4.2-rc7
- v4.2-rc6
- v4.2-rc5
- v4.2-rc4
- v4.2-rc3
- v4.2-rc2
- v4.2-rc1
- v4.2
- v4.19-rc8
- v4.19-rc7
- v4.19-rc6
- v4.19-rc5
- v4.19-rc4
- v4.19-rc3
- v4.19-rc2
- v4.19-rc1
- v4.19
- v4.18-rc8
- v4.18-rc7
- v4.18-rc6
- v4.18-rc5
- v4.18-rc4
- v4.18-rc3
- v4.18-rc2
- v4.18-rc1
- v4.18
- v4.17-rc7
- v4.17-rc6
- v4.17-rc5
- v4.17-rc4
- v4.17-rc3
- v4.17-rc2
- v4.17-rc1
- v4.17
- v4.16-rc7
- v4.16-rc6
- v4.16-rc5
- v4.16-rc4
- v4.16-rc3
- v4.16-rc2
- v4.16-rc1
- v4.16
- v4.15-rc9
- v4.15-rc8
- v4.15-rc7
- v4.15-rc6
- v4.15-rc5
- v4.15-rc4
- v4.15-rc3
- v4.15-rc2
- v4.15-rc1
- v4.15
- v4.14-rc8
- v4.14-rc7
- v4.14-rc6
- v4.14-rc5
- v4.14-rc4
- v4.14-rc3
- v4.14-rc2
- v4.14-rc1
- v4.14
- v4.13-rc7
- v4.13-rc6
- v4.13-rc5
- v4.13-rc4
- v4.13-rc3
- v4.13-rc2
- v4.13-rc1
- v4.13
- v4.12-rc7
- v4.12-rc6
- v4.12-rc5
- v4.12-rc4
- v4.12-rc3
- v4.12-rc2
- v4.12-rc1
- v4.12
- v4.11-rc8
- v4.11-rc7
- v4.11-rc6
- v4.11-rc5
- v4.11-rc4
- v4.11-rc3
- v4.11-rc2
- v4.11-rc1
- v4.11
- v4.10-rc8
- v4.10-rc7
- v4.10-rc6
- v4.10-rc5
- v4.10-rc4
- v4.10-rc3
- v4.10-rc2
- v4.10-rc1
- v4.10
- v4.1-rc8
- v4.1-rc7
- v4.1-rc6
- v4.1-rc5
- v4.1-rc4
- v4.1-rc3
- v4.1-rc2
- v4.1-rc1
- v4.1
- v4.0-rc7
- v4.0-rc6
- v4.0-rc5
- v4.0-rc4
- v4.0-rc3
- v4.0-rc2
- v4.0-rc1
- v4.0
- v3.9-rc8
- v3.9-rc7
- v3.9-rc6
- v3.9-rc5
- v3.9-rc4
- v3.9-rc3
- v3.9-rc2
- v3.9-rc1
- v3.9
- v3.8-rc7
- v3.8-rc6
- v3.8-rc5
- v3.8-rc4
- v3.8-rc3
- v3.8-rc2
- v3.8-rc1
- v3.8
- v3.7-rc8
- v3.7-rc7
- v3.7-rc6
- v3.7-rc5
- v3.7-rc4
- v3.7-rc3
- v3.7-rc2
- v3.7-rc1
- v3.7
- v3.6-rc7
- v3.6-rc6
- v3.6-rc5
- v3.6-rc4
- v3.6-rc3
- v3.6-rc2
- v3.6-rc1
- v3.6
- v3.5-rc7
- v3.5-rc6
- v3.5-rc5
- v3.5-rc4
- v3.5-rc3
- v3.5-rc2
- v3.5-rc1
- v3.5
- v3.4-rc7
- v3.4-rc6
- v3.4-rc5
- v3.4-rc4
- v3.4-rc3
- v3.4-rc2
- v3.4-rc1
- v3.4
- v3.3-rc7
- v3.3-rc6
- v3.3-rc5
- v3.3-rc4
- v3.3-rc3
- v3.3-rc2
- v3.3-rc1
- v3.3
- v3.2-rc7
- v3.2-rc6
- v3.2-rc5
- v3.2-rc4
- v3.2-rc3
- v3.2-rc2
- v3.2-rc1
- v3.2
- v3.19-rc7
- v3.19-rc6
- v3.19-rc5
- v3.19-rc4
- v3.19-rc3
- v3.19-rc2
- v3.19-rc1
- v3.19
- v3.18-rc7
- v3.18-rc6
- v3.18-rc5
- v3.18-rc4
- v3.18-rc3
- v3.18-rc2
- v3.18-rc1
- v3.18
- v3.17-rc7
- v3.17-rc6
- v3.17-rc5
- v3.17-rc4
- v3.17-rc3
- v3.17-rc2
- v3.17-rc1
- v3.17
- v3.16-rc7
- v3.16-rc6
- v3.16-rc5
- v3.16-rc4
- v3.16-rc3
- v3.16-rc2
- v3.16-rc1
- v3.16
- v3.15-rc8
- v3.15-rc7
- v3.15-rc6
- v3.15-rc5
- v3.15-rc4
- v3.15-rc3
- v3.15-rc2
- v3.15-rc1
- v3.15
- v3.14-rc8
- v3.14-rc7
- v3.14-rc6
- v3.14-rc5
- v3.14-rc4
- v3.14-rc3
- v3.14-rc2
- v3.14-rc1
- v3.14
- v3.13-rc8
- v3.13-rc7
- v3.13-rc6
- v3.13-rc5
- v3.13-rc4
- v3.13-rc3
- v3.13-rc2
- v3.13-rc1
- v3.13
- v3.12-rc7
- v3.12-rc6
- v3.12-rc5
- v3.12-rc4
- v3.12-rc3
- v3.12-rc2
- v3.12-rc1
- v3.12
- v3.11-rc7
- v3.11-rc6
- v3.11-rc5
- v3.11-rc4
- v3.11-rc3
- v3.11-rc2
- v3.11-rc1
- v3.11
- v3.10-rc7
- v3.10-rc6
- v3.10-rc5
- v3.10-rc4
- v3.10-rc3
- v3.10-rc2
- v3.10-rc1
- v3.10
- v3.1-rc9
- v3.1-rc8
- v3.1-rc7
- v3.1-rc6
- v3.1-rc5
- v3.1-rc4
- v3.1-rc3
- v3.1-rc2
- v3.1-rc10
- v3.1-rc1
- v3.1
- v3.0-rc7
- v3.0-rc6
- v3.0-rc5
- v3.0-rc4
- v3.0-rc3
- v3.0-rc2
- v3.0-rc1
- v3.0
- v2.6.39-rc7
- v2.6.39-rc6
- v2.6.39-rc5
- v2.6.39-rc4
- v2.6.39-rc3
- v2.6.39-rc2
- v2.6.39-rc1
- v2.6.39
- v2.6.38-rc8
- v2.6.38-rc7
- v2.6.38-rc6
- v2.6.38-rc5
- v2.6.38-rc4
- v2.6.38-rc3
- v2.6.38-rc2
- v2.6.38-rc1
- v2.6.38
- v2.6.37-rc8
- v2.6.37-rc7
- v2.6.37-rc6
- v2.6.37-rc5
- v2.6.37-rc4
- v2.6.37-rc3
- v2.6.37-rc2
- v2.6.37-rc1
- v2.6.37
- v2.6.36-rc8
- v2.6.36-rc7
- v2.6.36-rc6
- v2.6.36-rc5
- v2.6.36-rc4
- v2.6.36-rc3
- v2.6.36-rc2
- v2.6.36-rc1
- v2.6.36
- v2.6.35-rc6
- v2.6.35-rc5
- v2.6.35-rc4
- v2.6.35-rc3
- v2.6.35-rc2
- v2.6.35-rc1
- v2.6.35
- v2.6.34-rc7
- v2.6.34-rc6
- v2.6.34-rc5
- v2.6.34-rc4
- v2.6.34-rc3
- v2.6.34-rc2
- v2.6.34-rc1
- v2.6.34
- v2.6.33-rc8
- v2.6.33-rc7
- v2.6.33-rc6
- v2.6.33-rc5
- v2.6.33-rc4
- v2.6.33-rc3
- v2.6.33-rc2
- v2.6.33-rc1
- v2.6.33
- v2.6.32-rc8
- v2.6.32-rc7
- v2.6.32-rc6
- v2.6.32-rc5
- v2.6.32-rc4
- v2.6.32-rc3
- v2.6.32-rc1
- v2.6.32
- v2.6.31-rc9
- v2.6.31-rc8
- v2.6.31-rc7
- v2.6.31-rc6
- v2.6.31-rc5
- v2.6.31-rc4
- v2.6.31-rc3
- v2.6.31-rc2
- v2.6.31-rc1
- v2.6.31
- v2.6.30-rc8
- v2.6.30-rc7
- v2.6.30-rc6
- v2.6.30-rc5
- v2.6.30-rc4
- v2.6.30-rc3
- v2.6.30-rc2
- v2.6.30-rc1
- v2.6.30
- v2.6.29-rc8
- v2.6.29-rc7
- v2.6.29-rc6
- v2.6.29-rc5
- v2.6.29-rc4
- v2.6.29-rc3
- v2.6.29-rc2
- v2.6.29-rc1
- v2.6.29
- v2.6.28-rc9
- v2.6.28-rc8
- v2.6.28-rc7
- v2.6.28-rc6
- v2.6.28-rc5
- v2.6.28-rc4
- v2.6.28-rc3
- v2.6.28-rc2
- v2.6.28-rc1
- v2.6.28
- v2.6.27-rc9
- v2.6.27-rc8
- v2.6.27-rc7
- v2.6.27-rc6
- v2.6.27-rc5
- v2.6.27-rc4
- v2.6.27-rc3
- v2.6.27-rc2
- v2.6.27-rc1
- v2.6.27
- v2.6.26-rc9
- v2.6.26-rc8
- v2.6.26-rc7
- v2.6.26-rc6
- v2.6.26-rc5
- v2.6.26-rc4
- v2.6.26-rc3
- v2.6.26-rc2
- v2.6.26-rc1
- v2.6.26
- v2.6.25-rc9
- v2.6.25-rc8
- v2.6.25-rc7
- v2.6.25-rc6
- v2.6.25-rc5
- v2.6.25-rc4
- v2.6.25-rc3
- v2.6.25-rc2
- v2.6.25-rc1
- v2.6.25
- v2.6.24-rc8
- v2.6.24-rc7
- v2.6.24-rc6
- v2.6.24-rc5
- v2.6.24-rc4
- v2.6.24-rc3
- v2.6.24-rc2
- v2.6.24-rc1
- v2.6.24
- v2.6.23-rc9
- v2.6.23-rc8
- v2.6.23-rc7
- v2.6.23-rc6
- v2.6.23-rc5
- v2.6.23-rc4
- v2.6.23-rc3
- v2.6.23-rc2
- v2.6.23-rc1
- v2.6.23
- v2.6.22-rc7
- v2.6.22-rc6
- v2.6.22-rc5
- v2.6.22-rc4
- v2.6.22-rc3
- v2.6.22-rc2
- v2.6.22-rc1
- v2.6.22
- v2.6.21-rc7
- v2.6.21-rc6
- v2.6.21-rc5
- v2.6.21-rc4
- v2.6.21-rc3
- v2.6.21-rc2
- v2.6.21-rc1
- v2.6.21
- v2.6.20-rc7
- v2.6.20-rc6
- v2.6.20-rc5
- v2.6.20-rc4
- v2.6.20-rc3
- v2.6.20-rc2
- v2.6.20-rc1
- v2.6.20
- v2.6.19-rc6
- v2.6.19-rc5
- v2.6.19-rc4
- v2.6.19-rc3
- v2.6.19-rc2
- v2.6.19-rc1
- v2.6.19
- v2.6.18-rc7
- v2.6.18-rc6
- v2.6.18-rc5
- v2.6.18-rc4
- v2.6.18-rc3
- v2.6.18-rc2
- v2.6.18-rc1
- v2.6.18
- v2.6.17-rc6
- v2.6.17-rc5
- v2.6.17-rc4
- v2.6.17-rc3
- v2.6.17-rc2
- v2.6.17-rc1
- v2.6.17
- v2.6.16-rc6
- v2.6.16-rc5
- v2.6.16-rc4
- v2.6.16-rc3
- v2.6.16-rc2
- v2.6.16-rc1
- v2.6.16
- v2.6.15-rc7
- v2.6.15-rc6
- v2.6.15-rc5
- v2.6.15-rc4
- v2.6.15-rc3
- v2.6.15-rc2
- v2.6.15-rc1
- v2.6.15
- v2.6.14-rc5
- v2.6.14-rc4
- v2.6.14-rc3
- v2.6.14-rc2
- v2.6.14-rc1
- v2.6.14
- v2.6.13-rc7
- v2.6.13-rc6
- v2.6.13-rc5
- v2.6.13-rc4
- v2.6.13-rc3
- v2.6.13-rc2
- v2.6.13-rc1
- v2.6.13
- v2.6.12-rc6
- v2.6.12-rc5
- v2.6.12-rc4
- v2.6.12-rc3
- v2.6.12-rc2
- v2.6.12
- v2.6.11-tree
Raw File
Take a new snapshot of a software origin
If the archived software origin currently browsed is not synchronized with its upstream version (for instance when new commits have been issued), you can explicitly request Software Heritage to take a new snapshot of it.
Use the form below to proceed. Once a request has been submitted and accepted, it will be processed as soon as possible. You can then check its processing state by visiting this dedicated page.![swh spinner](/static/img/swh-spinner.gif)
Processing "take a new snapshot" request ...
Permalinks
To reference or cite the objects present in the Software Heritage archive, permalinks based on SoftWare Hash IDentifiers (SWHIDs) must be used.
Select below a type of object currently browsed in order to display its associated SWHID and permalink.
Tip revision: 97da3854c526d3a6ee05c849c96e48d21527606c authored by Linus Torvalds on 20 March 2017, 02:09:39 UTC
Linux 4.11-rc3
Linux 4.11-rc3
Tip revision: 97da385
percpu-rw-semaphore.txt
Percpu rw semaphores
--------------------
Percpu rw semaphores is a new read-write semaphore design that is
optimized for locking for reading.
The problem with traditional read-write semaphores is that when multiple
cores take the lock for reading, the cache line containing the semaphore
is bouncing between L1 caches of the cores, causing performance
degradation.
Locking for reading is very fast, it uses RCU and it avoids any atomic
instruction in the lock and unlock path. On the other hand, locking for
writing is very expensive, it calls synchronize_rcu() that can take
hundreds of milliseconds.
The lock is declared with "struct percpu_rw_semaphore" type.
The lock is initialized percpu_init_rwsem, it returns 0 on success and
-ENOMEM on allocation failure.
The lock must be freed with percpu_free_rwsem to avoid memory leak.
The lock is locked for read with percpu_down_read, percpu_up_read and
for write with percpu_down_write, percpu_up_write.
The idea of using RCU for optimized rw-lock was introduced by
Eric Dumazet <eric.dumazet@gmail.com>.
The code was written by Mikulas Patocka <mpatocka@redhat.com>