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>
*/
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);
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,