Messages in this thread |  | | Date | Tue, 6 Feb 2001 20:57:13 +0100 (CET) | From | Ingo Molnar <> | Subject | Re: [Kiobuf-io-devel] RFC: Kernel mechanism: Compound event wait |
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On Tue, 6 Feb 2001, Ben LaHaise wrote:
> This small correction is the crux of the problem: if it blocks, it > takes away from the ability of the process to continue doing useful > work. If it returns -EAGAIN, then that's okay, the io will be > resubmitted later when other disk io has completed. But, it should be > possible to continue servicing network requests or user io while disk > io is underway.
typical blocking point is waiting for page completion, not __wait_request(). But, this is really not an issue, NR_REQUESTS can be increased anytime. If NR_REQUESTS is large enough then think of it as the 'absolute upper limit of doing IO', and think of the blocking as 'the kernel pulling the brakes'.
[overhead of 512-byte bhs in the raw IO code is an artificial problem of the raw IO code.]
Ingo
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