Hi,
Since supporting to blk-mq, big pre-allocation for sg list is introduced,
this way is very unfriendly wrt. memory consumption.
There were Red Hat internal reports that some scsi_debug based tests
can't be run any more because of too big pre-allocation.
Also lpfc users commplained that 1GB+ ram is pre-allocatd for single
HBA.
The two patches try to address this issue by allocating sg list runtime,
meantime pre-allocating one or two inline sg entries for small IO. This
ways follows NVMe's approach wrt. sg list allocation.
V2:
- move inline sg table initializetion into one helper
- introduce new helper for getting inline sg
- comment log fix
Ming Lei (2):
scsi: core: avoid to pre-allocate big chunk for protection meta data
scsi: core: avoid to pre-allocate big chunk for sg list
drivers/scsi/scsi_lib.c | 78 ++++++++++++++++++++++++++++++++++---------------
1 file changed, 55 insertions(+), 23 deletions(-)
Cc: Christoph Hellwig <[email protected]>
Cc: Bart Van Assche <[email protected]>
Cc: Ewan D. Milne <[email protected]>
Cc: Hannes Reinecke <[email protected]>
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2.9.5
