Re: explicit dcache <-> user-space cache coherency, sys_mark_dir_clean(), O_CLEAN

[Jamie Lokier]

Christer Weinigel wrote:
> > 	long sys_mark_dir_clean(dirfd);
> > 
> > the syscall returns whether the directory was valid/clean already.
> 
> Isn't this rather bad, it's only possible to have one process that
> does this magic clean bit thing.  Other applications such as Wine or
> a DOS emulator might want to get the same speedups.

No.  The magic clean bit is associated with dirfd - different file
descriptors have separate magic clean bits.

> Add a new create syscall with the same idea as your one bit syscall,
> which checks that the generation number matches.  If the generation
> number doesn't match the create call fails.
> 
>     int create_synchronized(name, mode, generation);

Hmm.  That's an interesting idea.

-- Jamie
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