NVMe: Use CMB for the IO SQes if available

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Some controllers have a controller-side memory buffer available for use
for submissions, completions, lists, or data.

If a CMB is available, the entire CMB will be ioremapped and it will
attempt to map the IO SQes onto the CMB. The queues will be shrunk as
needed. The CMB will not be used if the queue depth is shrunk below some
threshold where it may have reduced performance over a larger queue
in system memory.

Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

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Jon Derrick 2015-07-20 10:14:09 -06:00 • committed by Jens Axboe

parent 498c43949c

commit 8ffaadf742

2 changed files with 134 additions and 5 deletions

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122

drivers/block/nvme-core.c

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17

include/linux/nvme.h

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