Re: [PATCH 12/14] scatterlist: allow chaining to preallocated chunks

From: Martin K. Petersen
Date: Fri Jul 25 2014 - 15:16:46 EST

>>>>> "Christoph" == Christoph Hellwig <hch@xxxxxx> writes:

Christoph> Blk-mq drivers usually preallocate their S/G list as part of
Christoph> the request, but if we want to support the very large S/G
Christoph> lists currently supported by the SCSI code that would tie up
Christoph> a lot of memory in the preallocated request pool. Add
Christoph> support to the scatterlist code so that it can initialize a
Christoph> S/G list that uses a preallocated first chunks and
Christoph> dynamically allocated additional chunks. That way the
Christoph> scsi-mq code can preallocate a first page worth of S/G
Christoph> entries as part of the request, and dynamically extend the
Christoph> S/G list when needed.

Reviewed-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>

Martin K. Petersen Oracle Linux Engineering
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