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author | SeongJae Park <sj38.park@gmail.com> | 2016-11-08 15:26:08 +0300 |
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committer | Jonathan Corbet <corbet@lwn.net> | 2016-11-13 21:49:52 +0300 |
commit | 9544a2daebbaf70bb61f0b02ae481532fc22a379 (patch) | |
tree | bca79ad7f0cddbe05101e735ec0aebe006f2c140 /Documentation/zh_CN/io_ordering.txt | |
parent | 3080b056b3d4e38bc4beac337acadf8bd286ac58 (diff) | |
download | linux-9544a2daebbaf70bb61f0b02ae481532fc22a379.tar.xz |
Documentation: Move translations into a sub-directory
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/zh_CN/io_ordering.txt')
-rw-r--r-- | Documentation/zh_CN/io_ordering.txt | 67 |
1 files changed, 0 insertions, 67 deletions
diff --git a/Documentation/zh_CN/io_ordering.txt b/Documentation/zh_CN/io_ordering.txt deleted file mode 100644 index e592daf4e014..000000000000 --- a/Documentation/zh_CN/io_ordering.txt +++ /dev/null @@ -1,67 +0,0 @@ -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 Contact the Chinese maintainer if this translation is outdated -or if there is a problem with the translation.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。 |