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Commit c1be5232 authored by Eli Cohen's avatar Eli Cohen Committed by Roland Dreier
Browse files

IB/mlx5: Fix micro UAR allocator 



The micro UAR (uuar) allocator had a bug which resulted from the fact
that in each UAR we only have two micro UARs avaialable, those at
index 0 and 1.  This patch defines iterators to aid in traversing the
list of available micro UARs when allocating a uuar.

In addition, change the logic in create_user_qp() so that if high
class allocation fails (high class means lower latency), we revert to
medium class and not to the low class.

Signed-off-by: default avatarEli Cohen <eli@mellanox.com>
Signed-off-by: default avatarRoland Dreier <roland@purestorage.com>
parent 24e42754

drivers/infiniband/hw/mlx5/main.c

+8 −5
Original line number Diff line number Diff line
@@ -541,6 +541,7 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev, 
	struct mlx5_ib_ucontext *context;

	struct mlx5_uuar_info *uuari;

	struct mlx5_uar *uars;

	int gross_uuars;

	int num_uars;

	int uuarn;

	int err;
@@ -559,11 +560,13 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev, 
	if (req.total_num_uuars == 0)

		return ERR_PTR(-EINVAL);



	req.total_num_uuars = ALIGN(req.total_num_uuars, MLX5_BF_REGS_PER_PAGE);

	req.total_num_uuars = ALIGN(req.total_num_uuars,

				    MLX5_NON_FP_BF_REGS_PER_PAGE);

	if (req.num_low_latency_uuars > req.total_num_uuars - 1)

		return ERR_PTR(-EINVAL);



	num_uars = req.total_num_uuars / MLX5_BF_REGS_PER_PAGE;

	num_uars = req.total_num_uuars / MLX5_NON_FP_BF_REGS_PER_PAGE;

	gross_uuars = num_uars * MLX5_BF_REGS_PER_PAGE;

	resp.qp_tab_size      = 1 << dev->mdev.caps.log_max_qp;

	resp.bf_reg_size      = dev->mdev.caps.bf_reg_size;

	resp.cache_line_size  = L1_CACHE_BYTES;
@@ -585,7 +588,7 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev, 
		goto out_ctx;

	}



	uuari->bitmap = kcalloc(BITS_TO_LONGS(req.total_num_uuars),

	uuari->bitmap = kcalloc(BITS_TO_LONGS(gross_uuars),

				sizeof(*uuari->bitmap),

				GFP_KERNEL);

	if (!uuari->bitmap) {
@@ -595,13 +598,13 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev, 
	/*

	 * clear all fast path uuars

	 */

	for (i = 0; i < req.total_num_uuars; i++) {

	for (i = 0; i < gross_uuars; i++) {

		uuarn = i & 3;

		if (uuarn == 2 || uuarn == 3)

			set_bit(i, uuari->bitmap);

	}



	uuari->count = kcalloc(req.total_num_uuars, sizeof(*uuari->count), GFP_KERNEL);

	uuari->count = kcalloc(gross_uuars, sizeof(*uuari->count), GFP_KERNEL);

	if (!uuari->count) {

		err = -ENOMEM;

		goto out_bitmap;

drivers/infiniband/hw/mlx5/qp.c

+58 −19
Original line number Diff line number Diff line
@@ -340,14 +340,57 @@ static int qp_has_rq(struct ib_qp_init_attr *attr) 
	return 1;

}



static int first_med_uuar(void)

{

	return 1;

}



static int next_uuar(int n)

{

	n++;



	while (((n % 4) & 2))

		n++;



	return n;

}



static int num_med_uuar(struct mlx5_uuar_info *uuari)

{

	int n;



	n = uuari->num_uars * MLX5_NON_FP_BF_REGS_PER_PAGE -

		uuari->num_low_latency_uuars - 1;



	return n >= 0 ? n : 0;

}



static int max_uuari(struct mlx5_uuar_info *uuari)

{

	return uuari->num_uars * 4;

}



static int first_hi_uuar(struct mlx5_uuar_info *uuari)

{

	int med;

	int i;

	int t;



	med = num_med_uuar(uuari);

	for (t = 0, i = first_med_uuar();; i = next_uuar(i)) {

		t++;

		if (t == med)

			return next_uuar(i);

	}



	return 0;

}



static int alloc_high_class_uuar(struct mlx5_uuar_info *uuari)

{

	int nuuars = uuari->num_uars * MLX5_BF_REGS_PER_PAGE;

	int start_uuar;

	int i;



	start_uuar = nuuars - uuari->num_low_latency_uuars;

	for (i = start_uuar; i < nuuars; i++) {

	for (i = first_hi_uuar(uuari); i < max_uuari(uuari); i = next_uuar(i)) {

		if (!test_bit(i, uuari->bitmap)) {

			set_bit(i, uuari->bitmap);

			uuari->count[i]++;
@@ -360,19 +403,10 @@ static int alloc_high_class_uuar(struct mlx5_uuar_info *uuari) 


static int alloc_med_class_uuar(struct mlx5_uuar_info *uuari)

{

	int nuuars = uuari->num_uars * MLX5_BF_REGS_PER_PAGE;

	int minidx = 1;

	int uuarn;

	int end;

	int minidx = first_med_uuar();

	int i;



	end = nuuars - uuari->num_low_latency_uuars;



	for (i = 1; i < end; i++) {

		uuarn = i & 3;

		if (uuarn == 2 || uuarn == 3)

			continue;



	for (i = first_med_uuar(); i < first_hi_uuar(uuari); i = next_uuar(i)) {

		if (uuari->count[i] < uuari->count[minidx])

			minidx = i;

	}
@@ -510,13 +544,18 @@ static int create_user_qp(struct mlx5_ib_dev *dev, struct ib_pd *pd, 
	uuarn = alloc_uuar(&context->uuari, MLX5_IB_LATENCY_CLASS_HIGH);

	if (uuarn < 0) {

		mlx5_ib_dbg(dev, "failed to allocate low latency UUAR\n");

		mlx5_ib_dbg(dev, "reverting to medium latency\n");

		uuarn = alloc_uuar(&context->uuari, MLX5_IB_LATENCY_CLASS_MEDIUM);

		if (uuarn < 0) {

			mlx5_ib_dbg(dev, "failed to allocate medium latency UUAR\n");

			mlx5_ib_dbg(dev, "reverting to high latency\n");

			uuarn = alloc_uuar(&context->uuari, MLX5_IB_LATENCY_CLASS_LOW);

			if (uuarn < 0) {

			mlx5_ib_dbg(dev, "uuar allocation failed\n");

				mlx5_ib_warn(dev, "uuar allocation failed\n");

				return uuarn;

			}

		}

	}



	uar_index = uuarn_to_uar_index(&context->uuari, uuarn);

	mlx5_ib_dbg(dev, "uuarn 0x%x, uar_index 0x%x\n", uuarn, uar_index);

include/linux/mlx5/device.h

+4 −3
Original line number Diff line number Diff line
@@ -106,7 +106,8 @@ enum { 
enum {

	MLX5_BF_REGS_PER_PAGE		= 4,

	MLX5_MAX_UAR_PAGES		= 1 << 8,

	MLX5_MAX_UUARS		= MLX5_MAX_UAR_PAGES * MLX5_BF_REGS_PER_PAGE,

	MLX5_NON_FP_BF_REGS_PER_PAGE	= 2,

	MLX5_MAX_UUARS	= MLX5_MAX_UAR_PAGES * MLX5_NON_FP_BF_REGS_PER_PAGE,

};



enum {