Re: Lockless file reading

[Nagendra Singh Tomar]

On Thu, 28 Aug 2003, Jamie Lokier wrote:

> Nagendra Singh Tomar wrote:
> > While the write had "12" in its buffers and it  would have grabbed the
> 
> > page lock to write it into the page cache, won't it set some flag
> saying 
> > that I don't want to be prempted now. I think there is a small
> primitive 
> > for it in from 2.5 onwards. I don't think it will be a good idea to
> prempt 
> > while it is holding the page lock. How is it possible that it just
> wrote 
> > "1" and did not write "2" though it had grabbed the page lock for that
> 
> > purpose. 
> 
> Nope.  I don't see any disabling of preemption while the page is held.
> 
> It wouldn't make sense anyway, because the copies to/from userspace
> can sleep, so there's nothing to gain by disabling preemption.

I understand  what you say. Thanx.

> 
> -- Jamie
> 

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