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.
sg_alloc_table_chained() is improved to support variant size of 1st
pre-allocated SGL in the 1st patch as suggested by Christoph.
The other 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.
V4:
- add parameter to sg_alloc_table_chained()/sg_free_table_chained()
directly, and update current callers
V3:
- improve sg_alloc_table_chained() to accept variant size of
the 1st pre-allocated SGL
- applies the improved sg API to address the big pre-allocation
issue
V2:
- move inline sg table initializetion into one helper
- introduce new helper for getting inline sg
- comment log fix
Ming Lei (3):
lib/sg_pool.c: improve APIs for allocating sg pool
scsi: core: avoid to pre-allocate big chunk for protection meta data
scsi: core: avoid to pre-allocate big chunk for sg list
drivers/nvme/host/fc.c | 7 ++++---
drivers/nvme/host/rdma.c | 7 ++++---
drivers/nvme/target/loop.c | 4 ++--
drivers/scsi/scsi_lib.c | 31 ++++++++++++++++++++++---------
include/linux/scatterlist.h | 11 +++++++----
lib/scatterlist.c | 36 +++++++++++++++++++++++-------------
lib/sg_pool.c | 37 +++++++++++++++++++++++++++----------
net/sunrpc/xprtrdma/svc_rdma_rw.c | 5 +++--
8 files changed, 92 insertions(+), 46 deletions(-)
Cc: Christoph Hellwig <h...@lst.de>
Cc: Bart Van Assche <bvanass...@acm.org>
Cc: Ewan D. Milne <emi...@redhat.com>
Cc: Hannes Reinecke <h...@suse.com>
Cc: Sagi Grimberg <s...@grimberg.me>
Cc: Chuck Lever <chuck.le...@oracle.com>
Cc: net...@vger.kernel.org
Cc: linux-n...@lists.infradead.org
--
2.9.5
