Unit Instance

HTTP 200 OK
Allow: GET, PUT, PATCH, DELETE, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "translation": "https://translate-dev.freebsd.org/api/translations/freebsd-doc/boooks_arch-handbook/zh_CN/?format=api",
    "source": [
        "Before calling the callback function from <function>bus_dmamap_load()</function> the segment array is stored in the stack. And it gets pre-allocated for the maximal number of segments allowed by the tag. As a result of this the practical limit for the number of segments on i386 architecture is about 250-300 (the kernel stack is 4KB minus the size of the user structure, size of a segment array entry is 8 bytes, and some space must be left). Since the array is allocated based on the maximal number this value must not be set higher than really needed. Fortunately, for most of hardware the maximal supported number of segments is much lower. But if the driver wants to handle buffers with a very large number of scatter-gather segments it should do that in portions: load part of the buffer, transfer it to the device, load next part of the buffer, and so on."
    ],
    "previous_source": "Before calling the callback function from <function>bus_dmamap_load()</function> the segment array is stored in the stack. And it gets pre-allocated for the maximal number of segments allowed by the tag. Because of this the practical limit for the number of segments on i386 architecture is about 250-300 (the kernel stack is 4KB minus the size of the user structure, size of a segment array entry is 8 bytes, and some space must be left). Because the array is allocated based on the maximal number this value must not be set higher than really needed. Fortunately, for most of hardware the maximal supported number of segments is much lower. But if the driver wants to handle buffers with a very large number of scatter-gather segments it should do that in portions: load part of the buffer, transfer it to the device, load next part of the buffer, and so on.",
    "target": [
        "从<function>bus_dmamap_load()</function>中调用回调函数之前，段数组是存储在栈中的。并且是按标签允许的最大数目的段预先分配好的。这样由于i386体系结构上对段数目的实际限制约为250-300（内核栈为4KB减去用户结构的大小，段数组条目的大小为8字节，和其它必须留出来的空间）。由于数组基于最大数目而分配，因此这个值必须不能设置成超出实际需要。幸运的是，对于大多数硬件而言，所支持的段的最大数目低很多。但如果驱动程序想处理具有非常多分散/收集段的缓冲区，则应当一部分一部分地处理：加载缓冲区的一部分，传输到设备，然后加载缓冲区的下一部分，如此反复。"
    ],
    "id_hash": 5944484303631366233,
    "content_hash": 5944484303631366233,
    "location": "book.translate.xml:17809",
    "context": "",
    "note": "(itstool) path: sect1/para",
    "flags": "",
    "labels": [],
    "state": 10,
    "fuzzy": true,
    "translated": false,
    "approved": false,
    "position": 1935,
    "has_suggestion": false,
    "has_comment": false,
    "has_failing_check": false,
    "num_words": 150,
    "source_unit": "https://translate-dev.freebsd.org/api/units/229393/?format=api",
    "priority": 100,
    "id": 229457,
    "web_url": "https://translate-dev.freebsd.org/translate/freebsd-doc/boooks_arch-handbook/zh_CN/?checksum=d27f0cfa9ad53859",
    "url": "https://translate-dev.freebsd.org/api/units/229457/?format=api",
    "explanation": "",
    "extra_flags": "",
    "pending": false,
    "timestamp": "2021-01-09T14:37:39.238470Z"
}