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/documentation/articlesvm-design_index/en/?format=api",
    "source": [
        "Taking a VM fault is not expensive if the underlying page is already in core and can simply be mapped into the process, but it can become expensive if you take a whole lot of them on a regular basis.  A good example of this is running a program such as man:ls[1] or man:ps[1] over and over again.  If the program binary is mapped into memory but not mapped into the page table, then all the pages that will be accessed by the program will have to be faulted in every time the program is run.  This is unnecessary when the pages in question are already in the VM Cache, so FreeBSD will attempt to pre-populate a process's page tables with those pages that are already in the VM Cache.  One thing that FreeBSD does not yet do is pre-copy-on-write certain pages on exec.  For example, if you run the man:ls[1] program while running `vmstat 1` you will notice that it always takes a certain number of page faults, even when you run it over and over again.  These are zero-fill faults, not program code faults (which were pre-faulted in already).  Pre-copying pages on exec or fork is an area that could use more study."
    ],
    "previous_source": "",
    "target": [
        "Taking a VM fault is not expensive if the underlying page is already in core and can simply be mapped into the process, but it can become expensive if you take a whole lot of them on a regular basis.  A good example of this is running a program such as man:ls[1] or man:ps[1] over and over again.  If the program binary is mapped into memory but not mapped into the page table, then all the pages that will be accessed by the program will have to be faulted in every time the program is run.  This is unnecessary when the pages in question are already in the VM Cache, so FreeBSD will attempt to pre-populate a process's page tables with those pages that are already in the VM Cache.  One thing that FreeBSD does not yet do is pre-copy-on-write certain pages on exec.  For example, if you run the man:ls[1] program while running `vmstat 1` you will notice that it always takes a certain number of page faults, even when you run it over and over again.  These are zero-fill faults, not program code faults (which were pre-faulted in already).  Pre-copying pages on exec or fork is an area that could use more study."
    ],
    "id_hash": -8125128984177974447,
    "content_hash": -8125128984177974447,
    "location": "documentation/content/en/articles/vm-design/_index.adoc:259",
    "context": "",
    "note": "type: Plain text",
    "flags": "",
    "labels": [],
    "state": 100,
    "fuzzy": false,
    "translated": true,
    "approved": false,
    "position": 55,
    "has_suggestion": false,
    "has_comment": false,
    "has_failing_check": false,
    "num_words": 205,
    "source_unit": "https://translate-dev.freebsd.org/api/units/615417/?format=api",
    "priority": 100,
    "id": 615417,
    "web_url": "https://translate-dev.freebsd.org/translate/documentation/articlesvm-design_index/en/?checksum=0f3dbe3cd7d76351",
    "url": "https://translate-dev.freebsd.org/api/units/615417/?format=api",
    "explanation": "",
    "extra_flags": "",
    "pending": false,
    "timestamp": "2021-03-20T20:43:35.175174Z"
}