mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 10:49:33 +00:00
nvme-fc: Avoid preallocating big SGL for data
nvme_fc_create_io_queues() preallocates a big buffer for the IO SGL based on SG_CHUNK_SIZE. Modern DMA engines are often capable of dealing with very big segments so the SG_CHUNK_SIZE is often too big. SG_CHUNK_SIZE results in a static 4KB SGL allocation per command. If a controller has lots of deep queues, preallocation for the sg list can consume substantial amounts of memory. For nvme-fc, nr_hw_queues can be 128 and each queue's depth 128. This means the resulting preallocation for the data SGL is 128*128*4K = 64MB per controller. Switch to runtime allocation for SGL for lists longer than 2 entries. This is the approach used by NVMe PCI so it should be reasonable for NVMeOF as well. Runtime SGL allocation has always been the case for the legacy I/O path so this is nothing new. Reviewed-by: Max Gurtovoy <maxg@mellanox.com> Reviewed-by: James Smart <james.smart@broadcom.com> Signed-off-by: Israel Rukshin <israelr@mellanox.com> Signed-off-by: Keith Busch <kbusch@kernel.org>
This commit is contained in:
parent
38e1800275
commit
b1ae1a2389
1 changed files with 4 additions and 4 deletions
|
@ -95,7 +95,7 @@ struct nvme_fc_fcp_op {
|
|||
|
||||
struct nvme_fcp_op_w_sgl {
|
||||
struct nvme_fc_fcp_op op;
|
||||
struct scatterlist sgl[SG_CHUNK_SIZE];
|
||||
struct scatterlist sgl[NVME_INLINE_SG_CNT];
|
||||
uint8_t priv[0];
|
||||
};
|
||||
|
||||
|
@ -2141,7 +2141,7 @@ nvme_fc_map_data(struct nvme_fc_ctrl *ctrl, struct request *rq,
|
|||
freq->sg_table.sgl = freq->first_sgl;
|
||||
ret = sg_alloc_table_chained(&freq->sg_table,
|
||||
blk_rq_nr_phys_segments(rq), freq->sg_table.sgl,
|
||||
SG_CHUNK_SIZE);
|
||||
NVME_INLINE_SG_CNT);
|
||||
if (ret)
|
||||
return -ENOMEM;
|
||||
|
||||
|
@ -2150,7 +2150,7 @@ nvme_fc_map_data(struct nvme_fc_ctrl *ctrl, struct request *rq,
|
|||
freq->sg_cnt = fc_dma_map_sg(ctrl->lport->dev, freq->sg_table.sgl,
|
||||
op->nents, rq_dma_dir(rq));
|
||||
if (unlikely(freq->sg_cnt <= 0)) {
|
||||
sg_free_table_chained(&freq->sg_table, SG_CHUNK_SIZE);
|
||||
sg_free_table_chained(&freq->sg_table, NVME_INLINE_SG_CNT);
|
||||
freq->sg_cnt = 0;
|
||||
return -EFAULT;
|
||||
}
|
||||
|
@ -2173,7 +2173,7 @@ nvme_fc_unmap_data(struct nvme_fc_ctrl *ctrl, struct request *rq,
|
|||
fc_dma_unmap_sg(ctrl->lport->dev, freq->sg_table.sgl, op->nents,
|
||||
rq_dma_dir(rq));
|
||||
|
||||
sg_free_table_chained(&freq->sg_table, SG_CHUNK_SIZE);
|
||||
sg_free_table_chained(&freq->sg_table, NVME_INLINE_SG_CNT);
|
||||
|
||||
freq->sg_cnt = 0;
|
||||
}
|
||||
|
|
Loading…
Reference in a new issue