Messages in this thread |  | | | Date | Sat, 7 Mar 1998 23:54:23 GMT | | From | "Stephen C. Tweedie" <> | | Subject | Re: mmap() versus read() |
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Hi,
On Fri, 06 Mar 1998 08:29:34 -0500, mlord <mlord@pobox.com> said:
> Alan Cox wrote: >> mmap doesnt do readahead on faults in 2.0.x, that increases the I/O load >> when paging mmap data versus read() quite a lot
> I wonder why we bother paging mmap'd data that could instead > be re-read from the original file on disk? Or did I read that wrong?
Hmm? Paging mmap()ed data *is* exactly the same as rereading it from the original file on disk. "Paging" refers to the pulling in of virtual memory pages from any location on disk, not necessarily from the swap file. The difference is only that mapped files get paged from their primary storage, whereas anonymous private data gets paged into and out of swap files.
--Stephen
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