Messages in this thread | | | Date | Sat, 10 Aug 2002 10:03:09 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [patch 6/12] hold atomic kmaps across generic_file_read |
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On Sat, 10 Aug 2002, Rik van Riel wrote: > On Sat, 10 Aug 2002, Linus Torvalds wrote: > > > and having it magically populate the VM directly with the whole file > > mapping, with _one_ failed page fault. And the above is actually a fairly > > common thing. See how many people have tried to optimize using mmap vs > > read, and what they _all_ really wanted was this "populate the pages in > > one go" thing. > > If this is worth it, chances are prefaulting at mmap() time > could also be worth trying ... hmmm ;)
Maybe, maybe not.
The advantage of read() is that it contains an implicit "madvise()", since the read _tells_ us that it wants X pages.
A page fault does not tell us, and prefaulting can hurt us.
Linus
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