Mon, Apr 29, 2019 at 04:17:39PM CEST, a...@mellanox.com wrote:
>TX reporter reports an error on two scenarios:
>- TX timeout on a specific tx queue
>- TX completion error on a specific send queue
>Prior to this patch, no dump data was supported by the tx reporter. This
>patch adds support for SW data dump of the related SQ context. The dump
>is simply the SQ's raw memory snapshot taken right after the error was
>reported, before any recovery procedure was launched. With this
>approach, no maintenance is needed as the driver fetch the actual data
>according to the layout on which the SQ was compiled with.  By providing
>a SW context, one can easily debug error on a given SQ.
>
>In order to offline translate the raw memory into a human readable
>format, the user can use some out-of-kernel scripts which receives as an
>input the following:
>- Object raw memory
>- Driver object compiled with debug info (can be taken/generated at any time 
>from the machine)
>- Object name
>
>An example of such script output can be seen below.
>Note: the script is not offered as part of this patch as it do not
>belong to the kernel, I just described it in order to grasp the general
>idea of how/what can be fetched from SW dump via devlink health.
>
>The output of the SW dump can be extracted by devlink health command:
>$ sudo devlink health dump show pci/0000:00:0b.0 reporter tx.
> mlx5e_txqsq: sqn: 6336
> memory:
>   00 00 00 00 00 00 00 00
>   01 00 00 00 00 00 00 00
>   00 00 00 00 00 00 00 00
>   45 f4 88 cb 09 00 00 00
>   00 00 00 00 00 00 00 00
>   00 00 00 00 00 00 00 00
>   c0 ff ff ff 1f 00 00 00
>   f8 18 1e 89 81 88 ff ff
>   ...
>
>script output below, with struct members names and actual values:
>
>struct  mlx5e_txqsq {
>       short unsigned int         cc    0x5 ;
>       unsigned int               dma_fifo_cc   0x5 ;
>       struct  net_dim {
>               unsigned char      state         0x1 ;
>               struct  net_dim_stats {
>                       int        ppms          0x0 ;
>                       int        bpms          0x0 ;
>                       int        epms          0x0 ;
>               } prev_stats;
>               struct  net_dim_sample {
>                       long long int time       0x90766ef9d ;
>                       unsigned int pkt_ctr     0x0 ;
>                       unsigned int byte_ctr    0x0 ;
>                       short unsigned int event_ctr     0x0 ;
>               } start_sample;
>               struct  work_struct {
>                       struct   {
>                               long int counter         0x1fffffffc0 ;
>                       } data;
>                       struct  list_head {
>                               struct list_head * next          
> 0xffff8881b08998f8 ;
>                               struct list_head * prev          
> 0xffff8881b08998f8 ;
>                       } entry;
>                       void       (*func)(struct work_struct *)         
> 0xffffffffa02d0e30 ;
>               } work;
>               unsigned char      profile_ix    0x60 ;
>               unsigned char      mode          0x72 ;
>               unsigned char      tune_state    0x35 ;
>               unsigned char      steps_right   0xa0 ;
>               unsigned char      steps_left    0xff ;
>               unsigned char      tired         0xff ;
>       } dim;
>       short unsigned int         pc    0x0 ;
>       unsigned int               dma_fifo_pc   0x0 ;
>       struct  mlx5e_cq {
>               struct  mlx5_cqwq {
>                       struct  mlx5_frag_buf_ctrl {
>                               struct mlx5_buf_list * frags     0x500000005 ;
>                               unsigned int sz_m1       0x0 ;
>                               short unsigned int frag_sz_m1    0x0 ;
>                               short unsigned int strides_offset        0x0 ;
>                               unsigned char log_sz     0x0 ;
>                               unsigned char log_stride         0x0 ;
>                               unsigned char log_frag_strides   0x0 ;
>                       } fbc;
>                       __be32 *   db    0x0 ;
>                       unsigned int cc          0x0 ;
>               } wq;
>               short unsigned int event_ctr     0x0 ;
>               struct napi_struct * napi        0x0 ;
>               struct  mlx5_core_cq {
>                       unsigned int cqn         0x0 ;
>                       int        cqe_sz        0x0 ;
>                       __be32 *   set_ci_db     0xffff8881b1aa4988 ;
>                       __be32 *   arm_db        0x3f000003ff ;
>                       struct mlx5_uars_page * uar      0x6060a ;
>                       struct  refcount_struct {
>                               struct   {
>                                       int    counter   0xa1814500 ;
>                               } refs;
>                       } refcount;
>                       struct  completion {
>                               unsigned int done        0x5 ;
>                               struct  wait_queue_head {
>                                       struct  spinlock {
>                                               union   {
>                                                       struct  raw_spinlock {
>                                                               struct  
> qspinlock {
>                                                                       union   
> {
>                                                                               
> struct   {
>                                                                               
>         int                                                    counter   0x5 ;
>                                                                               
> } val;
>                                                                               
> struct   {
>                                                                               
>         unsigned char                                          locked    0x5 ;
>                                                                               
>         unsigned char                                          pending   0x0 ;
>                                                                               
> } ;
>                                                                               
> struct   {
>                                                                               
>         short unsigned int                                     locked_pending 
>    0x5 ;
>                                                                               
>         short unsigned int                                     tail      0x0 ;
>                                                                               
> } ;
>                                                                       } ;
>                                                               } raw_lock;
>                                                       } rlock;
>                                               } ;
>                                       } lock;
>                                       struct  list_head {
>                                               struct list_head * next         
>  0xffff8881b089bb88 ;
>                                               struct list_head * prev         
>  0x4000000c0a ;
>                                       } head;
>                               } wait;
>                       } free;
>                       unsigned int vector      0xa1814500 ;
>                       unsigned int irqn        0xffff8881 ;
>                       void       (*comp)(struct mlx5_core_cq *)        
> 0xffff8881a1814504 ;
>                       void       (*event)(struct mlx5_core_cq *, enum 
> mlx5_event)      0xffff8881a2cdea08 ;
>                       unsigned int cons_index          0x1 ;
>                       unsigned int arm_sn      0x0 ;
>                       struct mlx5_rsc_debug * dbg      0x0 ;
>                       int        pid   0x0 ;
>                       struct   {
>                               struct  list_head {
>                                       struct list_head * next          
> 0xffffffff ;
>                                       struct list_head * prev          
> 0xffffffffffffffff ;
>                               } list;
>                               void (*comp)(struct mlx5_core_cq *)      
> 0xffffffffa0356940 ;
>                               void * priv      0x0 ;
>                       } tasklet_ctx;
>                       int        reset_notify_added    0x0 ;
>                       struct  list_head {
>                               struct list_head * next          
> 0xffffffffa0300700 ;
>                               struct list_head * prev          0xd ;
>                       } reset_notify;
>                       struct mlx5_eq_comp * eq         0x0 ;
>                       short unsigned int uid   0x9a70 ;
>               } mcq;
>               struct mlx5e_channel * channel   0xffff8881b0899a70 ;
>               struct mlx5_core_dev * mdev      0x4800000001 ;
>               struct  mlx5_wq_ctrl {
>                       struct mlx5_core_dev * mdev      0xffffffffa02d5350 ;
>                       struct  mlx5_frag_buf {
>                               struct mlx5_buf_list * frags     
> 0xffffffffa02d5460 ;
>                               int npages       0x0 ;
>                               int size         0x5 ;
>                               unsigned char page_shift         0x8 ;
>                       } buf;
>                       struct  mlx5_db {
>                               __be32 * db      0x1c6 ;
>                               union   {
>                                       struct mlx5_db_pgdir * pgdir     0x0 ;
>                                       struct mlx5_ib_user_db_page * user_page 
>          0x0 ;
>                               } u;
>                               long long unsigned int dma       
> 0xffff8881b0899ab0 ;
>                               int index        0x0 ;
>                       } db;
>               } wq_ctrl;
>       } cq;
>       struct  mlx5_wq_cyc {
>               struct  mlx5_frag_buf_ctrl {
>                       struct mlx5_buf_list * frags     0xffff8881a7600160 ;
>                       unsigned int sz_m1       0xa7600160 ;
>                       short unsigned int frag_sz_m1    0x8881 ;
>                       short unsigned int strides_offset        0xffff ;
>                       unsigned char log_sz     0x88 ;
>                       unsigned char log_stride         0x49 ;
>                       unsigned char log_frag_strides   0xaa ;
>               } fbc;
>               __be32 *           db    0x1000000000010 ;
>               short unsigned int sz    0xc ;
>               short unsigned int wqe_ctr       0x0 ;
>               short unsigned int cur_sz        0x0 ;
>       } wq;
>       unsigned int               dma_fifo_mask         0xa1814500 ;
>       struct mlx5e_sq_stats *    stats         0xffff8881a33a0348 ;
>       struct   {
>               struct mlx5e_sq_dma * dma_fifo   0x1a1814500 ;
>               struct mlx5e_tx_wqe_info * wqe_info      0x14 ;
>       } db;
>       void *                     uar_map       0x0 ;
>       struct netdev_queue *      txq   0x0 ;
>       unsigned int               sqn   0x18c0 ;
>       unsigned char              min_inline_mode       0x0 ;
>       struct device *            pdev          0x0 ;
>       unsigned int               mkey_be       0x0 ;
>       long unsigned int          state         0x0 ;
>       struct hwtstamp_config *   tstamp        0x0 ;
>       struct mlx5_clock *        clock         0xffff8881b1aa6f88 ;
>       struct  mlx5_wq_ctrl {
>               struct mlx5_core_dev * mdev      0x3f000003ff ;
>               struct  mlx5_frag_buf {
>                       struct mlx5_buf_list * frags     0x6060a ;
>                       int        npages        0xa1814604 ;
>                       int        size          0xffff8881 ;
>                       unsigned char page_shift         0x0 ;
>               } buf;
>               struct  mlx5_db {
>                       __be32 *   db    0xfff ;
>                       union   {
>                               struct mlx5_db_pgdir * pgdir     0x0 ;
>                               struct mlx5_ib_user_db_page * user_page         
>  0x0 ;
>                       } u;
>                       long long unsigned int dma       0xffff888188440000 ;
>                       int        index         0x8b074000 ;
>               } db;
>       } wq_ctrl;
>       struct mlx5e_channel *     channel       0xffffc9000010d800 ;
>       int                        txq_ix        0xa0020180 ;
>       unsigned int               rate_limit    0xffff8881 ;
>       struct  work_struct {
>               struct   {
>                       long int   counter       0x1000018c0 ;
>               } data;
>               struct  list_head {
>                       struct list_head * next          0xffff8881c32b68e8 ;
>                       struct list_head * prev          0x800 ;
>               } entry;
>               void               (*func)(struct work_struct *)         0x9 ;
>       } recover_work;
>} ;

I don't get it. You are dumping live kernel memory? There are already
facilities to do that in place. Why to replicate it?


>
>Signed-off-by: Aya Levin <a...@mellanox.com>
>---
> .../ethernet/mellanox/mlx5/core/en/reporter_tx.c   | 100 +++++++++++++++++++++
> 1 file changed, 100 insertions(+)
>
>diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/reporter_tx.c 
>b/drivers/net/ethernet/mellanox/mlx5/core/en/reporter_tx.c
>index 476dd97f7f2f..8a39f5525e57 100644
>--- a/drivers/net/ethernet/mellanox/mlx5/core/en/reporter_tx.c
>+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/reporter_tx.c
>@@ -9,6 +9,7 @@
> 
> struct mlx5e_tx_err_ctx {
>       int (*recover)(struct mlx5e_txqsq *sq);
>+      int (*dump)(struct mlx5e_txqsq *sq);
>       struct mlx5e_txqsq *sq;
> };
> 
>@@ -281,10 +282,109 @@ static int mlx5e_tx_reporter_diagnose(struct 
>devlink_health_reporter *reporter,
>       return err;
> }
> 
>+static int mlx5e_tx_reporter_sw_dump_from_ctx(struct mlx5e_priv *priv,
>+                                            struct mlx5e_txqsq *sq,
>+                                            struct devlink_fmsg *fmsg)
>+{
>+      u64 *ptr = (u64 *)sq;
>+      int copy, err;
>+      int i = 0;
>+
>+      if (!test_bit(MLX5E_STATE_OPENED, &priv->state))
>+              return 0;
>+
>+      err = devlink_fmsg_pair_nest_start(fmsg, "mlx5e_txqsq");
>+      if (err)
>+              return err;
>+
>+      err = devlink_fmsg_obj_nest_start(fmsg);
>+      if (err)
>+              return err;
>+
>+      err = devlink_fmsg_arr_pair_nest_start(fmsg, "memory");
>+      if (err)
>+              return err;
>+
>+      while (i < sizeof(struct mlx5e_txqsq)) {
>+              copy = sizeof(u64);
>+
>+              if (i + copy > sizeof(struct mlx5e_txqsq))
>+                      copy = sizeof(struct mlx5e_txqsq) - i;
>+
>+              err = devlink_fmsg_binary_put(fmsg, ptr, copy);
>+              if (err)
>+                      return err;
>+              ptr++;
>+              i += copy;
>+      }
>+
>+      err = devlink_fmsg_arr_pair_nest_end(fmsg);
>+      if (err)
>+              return err;
>+
>+      err = devlink_fmsg_obj_nest_end(fmsg);
>+      if (err)
>+              return err;
>+
>+      err = devlink_fmsg_pair_nest_end(fmsg);
>+
>+      return err;
>+}
>+
>+static int mlx5e_tx_reporter_sw_dump_all(struct mlx5e_priv *priv,
>+                                       struct devlink_fmsg *fmsg)
>+{
>+      int i, err = 0;
>+
>+      mutex_lock(&priv->state_lock);
>+
>+      if (!test_bit(MLX5E_STATE_OPENED, &priv->state))
>+              goto unlock;
>+
>+      err = devlink_fmsg_arr_pair_nest_start(fmsg, "SQs");
>+      if (err)
>+              goto unlock;
>+
>+      for (i = 0; i < priv->channels.num * priv->channels.params.num_tc;
>+           i++) {
>+              err = devlink_fmsg_obj_nest_start(fmsg);
>+              if (err)
>+                      goto unlock;
>+
>+              err = mlx5e_tx_reporter_sw_dump_from_ctx(priv, priv->txq2sq[i],
>+                                                       fmsg);
>+              if (err)
>+                      goto unlock;
>+
>+              err = devlink_fmsg_pair_nest_end(fmsg);
>+              if (err)
>+                      goto unlock;
>+      }
>+      err = devlink_fmsg_arr_pair_nest_end(fmsg);
>+      if (err)
>+              goto unlock;
>+
>+unlock:
>+      mutex_unlock(&priv->state_lock);
>+      return err;
>+}
>+
>+static int mlx5e_tx_reporter_sw_dump(struct devlink_health_reporter *reporter,
>+                                   struct devlink_fmsg *fmsg, void *context)
>+{
>+      struct mlx5e_priv *priv = devlink_health_reporter_priv(reporter);
>+      struct mlx5e_tx_err_ctx *err_ctx = context;
>+
>+      return err_ctx ? mlx5e_tx_reporter_sw_dump_from_ctx(priv, err_ctx->sq,
>+                                                          fmsg) :
>+                       mlx5e_tx_reporter_sw_dump_all(priv, fmsg);
>+}
>+
> static const struct devlink_health_reporter_ops mlx5_tx_reporter_ops = {
>               .name = "tx",
>               .recover = mlx5e_tx_reporter_recover,
>               .diagnose = mlx5e_tx_reporter_diagnose,
>+              .dump = mlx5e_tx_reporter_sw_dump,
> };
> 
> #define MLX5_REPORTER_TX_GRACEFUL_PERIOD 500
>-- 
>2.14.1
>

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