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: Eli Cohen <eli@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
index 7c6b4ba..a056c24 100644
--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c
@@ -340,14 +340,57 @@
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_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;
}
@@ -510,11 +544,16 @@
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 high latency\n");
- uuarn = alloc_uuar(&context->uuari, MLX5_IB_LATENCY_CLASS_LOW);
+ 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, "uuar allocation failed\n");
- return uuarn;
+ 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_warn(dev, "uuar allocation failed\n");
+ return uuarn;
+ }
}
}