Messages in this thread | | | From | "Stephen C. Tweedie" <> | Date | Fri, 18 Jun 1999 00:27:51 +0100 (BST) | Subject | Re: Non-blocking read |
| |
Hi,
On Mon, 14 Jun 1999 20:08:36 +0200 (CEST), Arjan van de Ven <arjan@fenrus.demon.nl> said:
> I want to do a non-blocking read from a file, from within the kernel. > Is this, at all, possible? I have been tracing how userspace does > this, but the userspace does not seem to be non-blocking either.
For regular files, that is correct. But...
> * non-blocking read is issued > * if the pages are in the pagecache, they are copied to my buffer > * if they are not, an asynchronous read-ahead is issued and the > read-funtion returns -EAGAIN
...to do this in the kernel, look at the readahead code: that populates the page cache asynchronously. There just isn't any high-level function which does that automatically for you: you need to do all the setup yourself.
--Stephen
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |