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Jack Morgenstein f95ccffc71 IB/mlx4: Use 4K pages for kernel QP's WQE buffer
In the current implementation, the driver tries to allocate contiguous
memory, and if it fails, it falls back to 4K fragmented allocation.

Once the memory is fragmented, the first allocation might take a lot
of time, and even fail, which can cause connection failures.

This patch changes the logic to always allocate with 4K granularity,
since it's more robust and more likely to succeed.

This patch was tested with Lustre and no performance degradation
was observed.

Note: This commit eliminates the "shrinking WQE" feature. This feature
depended on using vmap to create a virtually contiguous send WQ.
vmap use was abandoned due to problems with several processors (see the
commit cited below). As a result, shrinking WQE was available only with
physically contiguous send WQs. Allocating such send WQs caused the
problems described above.
Therefore, as a side effect of eliminating the use of large physically
contiguous send WQs, the shrinking WQE feature became unavailable.

Warning example:
worker/20:1: page allocation failure: order:8, mode:0x80d0
CPU: 20 PID: 513 Comm: kworker/20:1 Tainted: G OE ------------
Workqueue: ib_cm cm_work_handler [ib_cm]
Call Trace:
[<ffffffff81686d81>] dump_stack+0x19/0x1b
[<ffffffff81186160>] warn_alloc_failed+0x110/0x180
[<ffffffff8118a954>] __alloc_pages_nodemask+0x9b4/0xba0
[<ffffffff811ce868>] alloc_pages_current+0x98/0x110
[<ffffffff81184fae>] __get_free_pages+0xe/0x50
[<ffffffff8133f6fe>] swiotlb_alloc_coherent+0x5e/0x150
[<ffffffff81062551>] x86_swiotlb_alloc_coherent+0x41/0x50
[<ffffffffa056b4c4>] mlx4_buf_direct_alloc.isra.7+0xc4/0x180 [mlx4_core]
[<ffffffffa056b73b>] mlx4_buf_alloc+0x1bb/0x260 [mlx4_core]
[<ffffffffa0b15496>] create_qp_common+0x536/0x1000 [mlx4_ib]
[<ffffffff811c6ef7>] ? dma_pool_free+0xa7/0xd0
[<ffffffffa0b163c1>] mlx4_ib_create_qp+0x3b1/0xdc0 [mlx4_ib]
[<ffffffffa0b01bc2>] ? mlx4_ib_create_cq+0x2d2/0x430 [mlx4_ib]
[<ffffffffa0b21f20>] mlx4_ib_create_qp_wrp+0x10/0x20 [mlx4_ib]
[<ffffffffa08f152a>] ib_create_qp+0x7a/0x2f0 [ib_core]
[<ffffffffa06205d4>] rdma_create_qp+0x34/0xb0 [rdma_cm]
[<ffffffffa08275c9>] kiblnd_create_conn+0xbf9/0x1950 [ko2iblnd]
[<ffffffffa074077a>] ? cfs_percpt_unlock+0x1a/0xb0 [libcfs]
[<ffffffffa0835519>] kiblnd_passive_connect+0xa99/0x18c0 [ko2iblnd]

Fixes: 73898db043 ("net/mlx4: Avoid wrong virtual mappings")
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2018-07-30 20:25:46 -06:00
arch
block
certs
crypto
Documentation
drivers IB/mlx4: Use 4K pages for kernel QP's WQE buffer 2018-07-30 20:25:46 -06:00
firmware
fs fs/cifs: Simplify ib_post_(send|recv|srq_recv)() calls 2018-07-24 16:06:36 -06:00
include IB/uverbs: Add UVERBS_ATTR_FLAGS_IN to the specs language 2018-07-30 20:23:29 -06:00
init
ipc
kernel
lib
LICENSES
mm
net RDMA, core and ULPs: Declare ib_post_send() and ib_post_recv() arguments const 2018-07-30 20:09:34 -06:00
samples
scripts
security
sound
tools
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: Remove Dave Goodell from the usnic RDMA driver maintainer list 2018-07-23 15:41:18 -06:00
Makefile
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