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author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-12-12 21:58:13 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-12-12 21:58:13 -0800 |
commit | e7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba (patch) | |
tree | f63906f41699c8e38af9d12b063e2ceab0286ef2 /Documentation/translations/zh_CN/io_ordering.txt | |
parent | e34bac726d27056081d0250c0e173e4b155aa340 (diff) | |
parent | 868c97a846a73e937d835b09b8c885a69df50ec8 (diff) | |
download | op-kernel-dev-e7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba.zip op-kernel-dev-e7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba.tar.gz |
Merge tag 'docs-4.10' of git://git.lwn.net/linux
Pull documentation update from Jonathan Corbet:
"These are the documentation changes for 4.10.
It's another busy cycle for the docs tree, as the sphinx conversion
continues. Highlights include:
- Further work on PDF output, which remains a bit of a pain but
should be more solid now.
- Five more DocBook template files converted to Sphinx. Only 27 to
go... Lots of plain-text files have also been converted and
integrated.
- Images in binary formats have been replaced with more
source-friendly versions.
- Various bits of organizational work, including the renaming of
various files discussed at the kernel summit.
- New documentation for the device_link mechanism.
... and, of course, lots of typo fixes and small updates"
* tag 'docs-4.10' of git://git.lwn.net/linux: (193 commits)
dma-buf: Extract dma-buf.rst
Update Documentation/00-INDEX
docs: 00-INDEX: document directories/files with no docs
docs: 00-INDEX: remove non-existing entries
docs: 00-INDEX: add missing entries for documentation files/dirs
docs: 00-INDEX: consolidate process/ and admin-guide/ description
scripts: add a script to check if Documentation/00-INDEX is sane
Docs: change sh -> awk in REPORTING-BUGS
Documentation/core-api/device_link: Add initial documentation
core-api: remove an unexpected unident
ppc/idle: Add documentation for powersave=off
Doc: Correct typo, "Introdution" => "Introduction"
Documentation/atomic_ops.txt: convert to ReST markup
Documentation/local_ops.txt: convert to ReST markup
Documentation/assoc_array.txt: convert to ReST markup
docs-rst: parse-headers.pl: cleanup the documentation
docs-rst: fix media cleandocs target
docs-rst: media/Makefile: reorganize the rules
docs-rst: media: build SVG from graphviz files
docs-rst: replace bayer.png by a SVG image
...
Diffstat (limited to 'Documentation/translations/zh_CN/io_ordering.txt')
-rw-r--r-- | Documentation/translations/zh_CN/io_ordering.txt | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/Documentation/translations/zh_CN/io_ordering.txt b/Documentation/translations/zh_CN/io_ordering.txt new file mode 100644 index 0000000..e592daf --- /dev/null +++ b/Documentation/translations/zh_CN/io_ordering.txt @@ -0,0 +1,67 @@ +Chinese translated version of Documentation/io_orderings.txt + +If you have any comment or update to the content, please contact the +original document maintainer directly. However, if you have a problem +communicating in English you can also ask the Chinese maintainer for +help. Contact the Chinese maintainer if this translation is outdated +or if there is a problem with the translation. + +Chinese maintainer: Lin Yongting <linyongting@gmail.com> +--------------------------------------------------------------------- +Documentation/io_ordering.txt 的中文翻译 + +如果想评论或更新本文的内容,请直接联系原文档的维护者。如果你使用英文 +交流有困难的话,也可以向中文版维护者求助。如果本翻译更新不及时或者翻 +译存在问题,请联系中文版维护者。 + +中文版维护者: 林永听 Lin Yongting <linyongting@gmail.com> +中文版翻译者: 林永听 Lin Yongting <linyongting@gmail.com> +中文版校译者: 林永听 Lin Yongting <linyongting@gmail.com> + + +以下为正文 +--------------------------------------------------------------------- + +在某些平台上,所谓的内存映射I/O是弱顺序。在这些平台上,驱动开发者有责任 +保证I/O内存映射地址的写操作按程序图意的顺序达到设备。通常读取一个“安全” +设备寄存器或桥寄存器,触发IO芯片清刷未处理的写操作到达设备后才处理读操作, +而达到保证目的。驱动程序通常在spinlock保护的临界区退出之前使用这种技术。 +这也可以保证后面的写操作只在前面的写操作之后到达设备(这非常类似于内存 +屏障操作,mb(),不过仅适用于I/O)。 + +假设一个设备驱动程的具体例子: + + ... +CPU A: spin_lock_irqsave(&dev_lock, flags) +CPU A: val = readl(my_status); +CPU A: ... +CPU A: writel(newval, ring_ptr); +CPU A: spin_unlock_irqrestore(&dev_lock, flags) + ... +CPU B: spin_lock_irqsave(&dev_lock, flags) +CPU B: val = readl(my_status); +CPU B: ... +CPU B: writel(newval2, ring_ptr); +CPU B: spin_unlock_irqrestore(&dev_lock, flags) + ... + +上述例子中,设备可能会先接收到newval2的值,然后接收到newval的值,问题就 +发生了。不过很容易通过下面方法来修复: + + ... +CPU A: spin_lock_irqsave(&dev_lock, flags) +CPU A: val = readl(my_status); +CPU A: ... +CPU A: writel(newval, ring_ptr); +CPU A: (void)readl(safe_register); /* 配置寄存器?*/ +CPU A: spin_unlock_irqrestore(&dev_lock, flags) + ... +CPU B: spin_lock_irqsave(&dev_lock, flags) +CPU B: val = readl(my_status); +CPU B: ... +CPU B: writel(newval2, ring_ptr); +CPU B: (void)readl(safe_register); /* 配置寄存器?*/ +CPU B: spin_unlock_irqrestore(&dev_lock, flags) + +在解决方案中,读取safe_register寄存器,触发IO芯片清刷未处理的写操作, +再处理后面的读操作,防止引发数据不一致问题。 |