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Message-ID: <a9cc0437-163c-53a1-92e9-64767e23b585@mellanox.com>
Date: Tue, 7 May 2019 12:58:32 +0000
From: Aya Levin <ayal@...lanox.com>
To: Jiri Pirko <jiri@...nulli.us>
CC: "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
Eran Ben Elisha <eranbe@...lanox.com>,
Saeed Mahameed <saeedm@...lanox.com>,
Jiri Pirko <jiri@...lanox.com>
Subject: Re: [PATCH net-next RFC] Dump SW SQ context as part of tx reporter
On 5/7/2019 3:41 PM, Jiri Pirko wrote:
> Mon, Apr 29, 2019 at 04:17:39PM CEST, ayal@...lanox.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?
I am dumping the driver's memory under a lock so I can ensure it's
consistency (as appose to /dev/mem)
vmcore cannot be taken from a live kernel (without crashing).
I need the memory's snapshot right after the error from the driver's
context.
Which other tools do you mean?
>
>
>>
>> Signed-off-by: Aya Levin <ayal@...lanox.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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