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IB/mlx5: Maintain a single emergency page

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The mlx5 driver needs to be able to issue invalidation to ODP MRs
even if it cannot allocate memory. To this end it preallocates
emergency pages to use when the situation arises.

This flow should be extremely rare enough, that we don't need
to worry about contention and therefore a single emergency page
is good enough.

Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Ilya Lesokhin
2018-03-13 15:18:48 +02:00
committed by Doug Ledford
parent 65edd0e758
commit c44ef998f2
3 changed files with 38 additions and 23 deletions
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11
drivers/infiniband/hw/mlx5/mr.c
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@@ -985,7 +985,6 @@ int mlx5_ib_update_xlt(struct mlx5_ib_mr *mr, u64 idx, int npages,
{
struct mlx5_ib_dev *dev = mr->dev;
struct device *ddev = dev->ib_dev.dev.parent;
struct mlx5_ib_ucontext *uctx = NULL;
int size;
void *xlt;
dma_addr_t dma;
@@ -1001,6 +1000,7 @@ int mlx5_ib_update_xlt(struct mlx5_ib_mr *mr, u64 idx, int npages,
size_t pages_to_map = 0;
size_t pages_iter = 0;
gfp_t gfp;
bool use_emergency_page = false;
/* UMR copies MTTs in units of MLX5_UMR_MTT_ALIGNMENT bytes,
* so we need to align the offset and length accordingly
@@ -1027,12 +1027,11 @@ int mlx5_ib_update_xlt(struct mlx5_ib_mr *mr, u64 idx, int npages,
}
if (!xlt) {
uctx = to_mucontext(mr->ibmr.pd->uobject->context);
mlx5_ib_warn(dev, "Using XLT emergency buffer\n");
xlt = (void *)mlx5_ib_get_xlt_emergency_page();
size = PAGE_SIZE;
xlt = (void *)uctx->upd_xlt_page;
mutex_lock(&uctx->upd_xlt_page_mutex);
memset(xlt, 0, size);
use_emergency_page = true;
}
pages_iter = size / desc_size;
dma = dma_map_single(ddev, xlt, size, DMA_TO_DEVICE);
@@ -1096,8 +1095,8 @@ int mlx5_ib_update_xlt(struct mlx5_ib_mr *mr, u64 idx, int npages,
dma_unmap_single(ddev, dma, size, DMA_TO_DEVICE);
free_xlt:
if (uctx)
mutex_unlock(&uctx->upd_xlt_page_mutex);
if (use_emergency_page)
mlx5_ib_put_xlt_emergency_page();
else
free_pages((unsigned long)xlt, get_order(size));