Re: Linux 2.6.17-rc2

[Jens Axboe <axboe@suse.de>]

On Wed, Apr 19 2006, Linus Torvalds wrote:
> There are some other buffer management system calls that I haven't done 
> yet (and when I say "I haven't done yet", I obviously mean "that I hope 
> some other sucker will do for me, since I'm lazy"), but that are obvious 
> future extensions:

Well it's worked so far, hasn't it? :-)

>  - an ioctl/fcntl to set the maximum size of the buffer. Right now it's 
>    hardcoded to 16 "buffer entries" (which in turn are normally limited to 
>    one page each, although there's nothing that _requires_ that a buffer 
>    entry always be a page).

This is on a TODO, but not very high up since I've yet to see a case
where the current 16 page limitation is an issue. I'm sure something
will come up eventually, but until then I'd rather not bother.

>  - vmsplice() system call to basically do a "write to the buffer", but 
>    using the reference counting and VM traversal to actually fill the 
>    buffer. This means that the user needs to be careful not to re-use the 
>    user-space buffer it spliced into the kernel-space one (contrast this 
>    to "write()", which copies the actual data, and you can thus re-use the 
>    buffer immediately after a successful write), but that is often easy to 
>    do.

This I already did, it was pretty easy and straight forward. I'll post
it soonish.

-- 
Jens Axboe

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