Re: [PATCH] O_STREAMING - flag for optimal streaming I/O

From: Andrew Morton (akpm@digeo.com)
Date: Wed Oct 09 2002 - 03:43:35 EST


Giuliano Pochini wrote:
>
> > The point of O_STREAMING is one change: drop pages in the pagecache
> > behind our current position, that are free-able, because we know we will
> > never want them.
>
> Does it drop pages unconditionally ?

Yup.

> What happens if I do a
> streaming_cat largedatabase > /dev/null while other processes
> are working on it ?

You'll make your database run really slowly.

> It's not a good thing to remove the whole
> cached data other apps are working on.
>

Don't do that then ;)

Seriously, there are tons of ways of creating local performance
DoS'es of this form. fsync is an excellent tool for that.
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