Messages in this thread |  | | Date | Mon, 5 Feb 2001 23:16:47 +0000 | From | "Stephen C. Tweedie" <> | Subject | Re: [Kiobuf-io-devel] RFC: Kernel mechanism: Compound event wait /notify + callback chains |
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Hi,
On Mon, Feb 05, 2001 at 11:06:48PM +0000, Alan Cox wrote: > > do you then tell the application _above_ raid0 if one of the > > underlying IOs succeeds and the other fails halfway through? > > struct > { > u32 flags; /* because everything needs flags */ > struct io_completion *completions; > kiovec_t sglist[0]; > } thingy; > > now kmalloc one object of the header the sglist of the right size and the > completion list. Shove the completion list on the end of it as another > array of objects and what is the problem.
XFS uses both small metadata items in the buffer cache and large pagebufs. You may have merged a 512-byte read with a large pagebuf read: one completion callback is associated with a single sg fragment, the next callback belongs to a dozen different fragments. Associating the two lists becomes non-trivial, although it could be done.
--Stephen - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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