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>
author: Eli Cohen <eli@dev.mellanox.co.il> 2014-01-14 10:45:12 -0500
committer: Roland Dreier <roland@purestorage.com> 2014-01-14 16:54:23 -0500
commit: c1be5232d21de68f46637e617225b9b7c586451a (patch)
tree: ca552be072b1ec232a4ca7b1d3154fd6b5f4946f /drivers/infiniband/hw/mlx5
parent: 24e42754f676d34e5c26d6b7b30f36df8004ec08 (diff)
2 files changed, 66 insertions, 24 deletions
diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 306534109627..9660d093f8cf 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -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;
diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
index 7c6b4ba49bec..a056c243ddcd 100644
--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c
@@ -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 = first_hi_uuar(uuari); i < max_uuari(uuari); i = next_uuar(i)) {
-        for (i = start_uuar; i < nuuars; 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 = first_med_uuar();
-        int minidx = 1;
-        int uuarn;
-        int end;
        int i;
-        end = nuuars - uuari->num_low_latency_uuars;
+        for (i = first_med_uuar(); i < first_hi_uuar(uuari); i = next_uuar(i)) {
-        for (i = 1; i < end; i++) {
-                uuarn = i & 3;
-                if (uuarn == 2 || uuarn == 3)
-                        continue;
                if (uuari->count[i] < uuari->count[minidx])
                        minidx = i;
        }
@@ -510,11 +544,16 @@ 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 high latency\n");
+                mlx5_ib_dbg(dev, "reverting to medium latency\n");
-                uuarn = alloc_uuar(&context->uuari, MLX5_IB_LATENCY_CLASS_LOW);
+                uuarn = alloc_uuar(&context->uuari, MLX5_IB_LATENCY_CLASS_MEDIUM);
                if (uuarn < 0) {
-                        mlx5_ib_dbg(dev, "uuar allocation failed\n");
+                        mlx5_ib_dbg(dev, "failed to allocate medium latency UUAR\n");
-                        return uuarn;
+                        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;
+                        }
                }
        }
author	Eli Cohen <eli@dev.mellanox.co.il>	2014-01-14 10:45:12 -0500
committer	Roland Dreier <roland@purestorage.com>	2014-01-14 16:54:23 -0500
commit	c1be5232d21de68f46637e617225b9b7c586451a (patch)
tree	ca552be072b1ec232a4ca7b1d3154fd6b5f4946f /drivers/infiniband/hw/mlx5
parent	24e42754f676d34e5c26d6b7b30f36df8004ec08 (diff)