Messages in this thread | | | Date | Wed, 11 Jun 2014 13:09:17 -0400 | From | Matthew Wilcox <> | Subject | Re: [PATCH v7] NVMe: conversion to blk-mq |
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On Wed, Jun 11, 2014 at 10:54:52AM -0600, Jens Axboe wrote: > OK, so essentially any single request must be a virtually contig piece > of memory. Is there any size limitations to how big this contig segment > can be?
The maximum size of an I/O is 65536 sectors. So on a 512-byte sector device, that's 32MB, but on a 4k sector size device, that's 128MB.
> I think this is unique requirement, at least I haven't seen other pieces > of hardware have it. But it would be pretty trivial to add a setting to > limit merges based on virtually contig, similarly to what is done for > number of physical segments.
I think there might be an FCoE device with that requirement too.
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