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authorBart Van Assche <bart.vanassche@sandisk.com>2016-06-23 09:35:48 +0200
committerDoug Ledford <dledford@redhat.com>2016-06-23 12:04:09 -0400
commitc0cf4512a31eb3cec70b066bc36ed55f7d05b8c0 (patch)
tree425a9e164eb5b194fc4ed8b74882d91db439daa2
parent37e07cdafc111dfb7ce27e70e73d900d7cf2920c (diff)
downloadlinux-c0cf4512a31eb3cec70b066bc36ed55f7d05b8c0.tar.gz
IB/srpt: Reduce QP buffer size
The memory needed for the send and receive queues associated with a QP is proportional to the max_sge parameter. The current value of that parameter is such that with an mlx4 HCA the QP buffer size is 8 MB. Since DMA is used for communication between HCA and CPU that buffer either has to be allocated coherently or map_single() must succeed for that buffer. Since large contiguous allocations are fragile and since the maximum segment size for e.g. swiotlb is 256 KB, reduce the max_sge parameter. This patch avoids that the following text appears on the console after SRP logout and relogin on a system equipped with multiple IB HCAs: mlx4_core 0000:05:00.0: swiotlb buffer is full (sz: 8388608 bytes) swiotlb: coherent allocation failed for device 0000:05:00.0 size=8388608 CPU: 11 PID: 148 Comm: kworker/11:1 Not tainted 4.7.0-rc4-dbg+ #1 Call Trace: [<ffffffff812c6d35>] dump_stack+0x67/0x92 [<ffffffff812efe71>] swiotlb_alloc_coherent+0x141/0x150 [<ffffffff810458be>] x86_swiotlb_alloc_coherent+0x3e/0x50 [<ffffffffa03861fa>] mlx4_buf_direct_alloc.isra.5+0x9a/0x120 [mlx4_core] [<ffffffffa0386545>] mlx4_buf_alloc+0x165/0x1a0 [mlx4_core] [<ffffffffa035053d>] create_qp_common.isra.29+0x57d/0xff0 [mlx4_ib] [<ffffffffa03510da>] mlx4_ib_create_qp+0x12a/0x3f0 [mlx4_ib] [<ffffffffa031154a>] ib_create_qp+0x3a/0x250 [ib_core] [<ffffffffa055dd4b>] srpt_cm_handler+0x4bb/0xcad [ib_srpt] [<ffffffffa02c1ab0>] cm_process_work+0x20/0xf0 [ib_cm] [<ffffffffa02c3640>] cm_work_handler+0x1ac0/0x2059 [ib_cm] [<ffffffff810737ed>] process_one_work+0x19d/0x490 [<ffffffff81073b29>] worker_thread+0x49/0x490 [<ffffffff8107a0ea>] kthread+0xea/0x100 [<ffffffff815b25af>] ret_from_fork+0x1f/0x40 Fixes: b99f8e4d7bcd ("IB/srpt: convert to the generic RDMA READ/WRITE API") Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Laurence Oberman <loberman@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Doug Ledford <dledford@redhat.com>
-rw-r--r--drivers/infiniband/ulp/srpt/ib_srpt.c3
-rw-r--r--drivers/infiniband/ulp/srpt/ib_srpt.h1
2 files changed, 2 insertions, 2 deletions
diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index e68b20cba70b..4a4155640d51 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -1638,8 +1638,7 @@ retry:
*/
qp_init->cap.max_send_wr = srp_sq_size / 2;
qp_init->cap.max_rdma_ctxs = srp_sq_size / 2;
- qp_init->cap.max_send_sge = max(sdev->device->attrs.max_sge_rd,
- sdev->device->attrs.max_sge);
+ qp_init->cap.max_send_sge = SRPT_DEF_SG_PER_WQE;
qp_init->port_num = ch->sport->port;
ch->qp = ib_create_qp(sdev->pd, qp_init);
diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.h b/drivers/infiniband/ulp/srpt/ib_srpt.h
index fee6bfd7ca21..389030487da7 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.h
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.h
@@ -106,6 +106,7 @@ enum {
SRP_LOGIN_RSP_MULTICHAN_MAINTAINED = 0x2,
SRPT_DEF_SG_TABLESIZE = 128,
+ SRPT_DEF_SG_PER_WQE = 16,
MIN_SRPT_SQ_SIZE = 16,
DEF_SRPT_SQ_SIZE = 4096,