Hi Lianbo,
Thank you for the update, much better structure :)
Let's go into detail...
On 2022/05/30 18:15, Lianbo Jiang wrote:
> Currently, crash doesn't support to display disk I/O statistics
> for blk-mq devices. For more details, please refer to the following
> commit: <98b417fc6346> ("Handle blk_mq_ctx member changes for kernels
> 5.16-rc1 and later").
>
> Lets parse the bitmap in blk-mq layer to achieve it.
>
> Signed-off-by: Lianbo Jiang <lijiang@xxxxxxxxxx>
> ---
> defs.h | 11 +++
> dev.c | 261 ++++++++++++++++++++++++++++++++++++++++++++++--------
> symbols.c | 22 +++++
> 3 files changed, 255 insertions(+), 39 deletions(-)
>
> diff --git a/defs.h b/defs.h
> index c8444b4e54eb..2681586a33dc 100644
> --- a/defs.h
> +++ b/defs.h
> @@ -2170,6 +2170,16 @@ struct offset_table { /* stash of commonly-used offsets */
> long sbq_wait_state_wait;
> long sbitmap_alloc_hint;
> long sbitmap_round_robin;
> + long request_cmd_flags;
> + long request_q;
> + long request_state;
> + long request_queue_queue_hw_ctx;
> + long request_queue_nr_hw_queues;
> + long blk_mq_hw_ctx_tags;
> + long blk_mq_tags_bitmap_tags;
> + long blk_mq_tags_breserved_tags;
> + long blk_mq_tags_nr_reserved_tags;
> + long blk_mq_tags_rqs;
> };
>
> struct size_table { /* stash of commonly-used sizes */
> @@ -2339,6 +2349,7 @@ struct size_table { /* stash of commonly-used sizes */
> long sbitmap;
> long sbitmap_queue;
> long sbq_wait_state;
> + long blk_mq_tags;
> };
>
> struct array_table {
> diff --git a/dev.c b/dev.c
> index a493e51ac95c..c0240f7b889b 100644
> --- a/dev.c
> +++ b/dev.c
> @@ -4238,19 +4238,193 @@ get_one_mctx_diskio(unsigned long mctx, struct diskio *io)
> io->write = (dispatch[1] - comp[1]);
> }
>
> +typedef bool (busy_tag_iter_fn)(ulong rq, void *data);
> +
> +struct bt_iter_data {
I think that some names are confusing and not synced with the kernel.
How about renaming to "mq_inflight"?
> + ulong q;
> + struct diskio *dio;
> +};
> +
> +struct bt_tags_iter_data {
And please rename this to "bt_iter_data".
> + ulong tags;
> + uint flags;
rename to "reserved".
> + uint nr_reserved_tags;
> + busy_tag_iter_fn *fn;
> + void *data;
> +};
> +
> +/*
> + * See the include/linux/blk_types.h and include/linux/blk-mq.h
> + */
> +#define MQ_RQ_IN_FLIGHT 1
> +#define REQ_OP_BITS 8
> +#define REQ_OP_MASK ((1 << REQ_OP_BITS) - 1)
> +
> +static uint op_is_write(uint op)
> +{
> + return (op & REQ_OP_MASK) & 1;
> +}
> +
> +static bool mq_check_inflight(ulong rq, void *data)
> +{
> + uint cmd_flags = 0, state = 0;
> + ulong addr = 0, queue = 0;
> + struct bt_iter_data *iter = data;
> +
> + if (!IS_KVADDR(rq))
> + return TRUE;
Why return TRUE?
Does this mean that rq can be invalid with bit on?
> +
> + addr = rq + OFFSET(request_q);
> + if (!readmem(addr, KVADDR, &queue, sizeof(ulong), "request.q", RETURN_ON_ERROR))
> + return FALSE;
> +
> + addr = rq + OFFSET(request_cmd_flags);
> + if (!readmem(addr, KVADDR, &cmd_flags, sizeof(uint), "request.cmd_flags", RETURN_ON_ERROR))
> + return FALSE;
> +
> + addr = rq + OFFSET(request_state);
> + if (!readmem(addr, KVADDR, &state, sizeof(uint), "request.state", RETURN_ON_ERROR))
> + return FALSE;
Rethinking these, RETURN_ON_ERROR leads to stop counting (i.e. wrong results)
with error messages. I think it would be better to use FAULT_ON_ERROR unless
we can ignore or handle an error correctly. What do you think?
(And for the RETURN_ON_ERRORs below, same as above.)
> +
> + if (queue == iter->q && state == MQ_RQ_IN_FLIGHT) {
> + if (op_is_write(cmd_flags))
> + iter->dio->write++;
> + else
> + iter->dio->read++;
> + }
> +
> + return TRUE;
> +}
> +
> +static bool bt_tags_iter(uint bitnr, void *data)
> +{
> + ulong addr = 0, rqs_addr = 0, rq = 0;
> + struct bt_tags_iter_data *tag_iter = data;
> + ulong tag = tag_iter->tags;
> +
> + if (!tag_iter->flags)
> + bitnr += tag_iter->nr_reserved_tags;
> +
> + /* rqs */
> + addr = tag + OFFSET(blk_mq_tags_rqs);
> + if (!readmem(addr, KVADDR, &rqs_addr, sizeof(void *), "blk_mq_tags.rqs", RETURN_ON_ERROR))
> + return FALSE;
> +
> + addr = rqs_addr + bitnr * sizeof(ulong); /* rqs[bitnr] */
> + if (!readmem(addr, KVADDR, &rq, sizeof(ulong), "blk_mq_tags.rqs[]", RETURN_ON_ERROR))
> + return FALSE;
> +
> + return tag_iter->fn(rq, tag_iter->data);
> +}
> +
> +static void bt_tags_for_each(ulong q, ulong tags, ulong sbq, uint flags, uint nr_resvd_tags, struct diskio *dio)
Please rename this to bt_for_each.
> +{
> + struct sbitmap_context sc = {0};
> + struct diskio tmp = {0};
This tmp can be removed?
(The dio->{read,write} are incremented in mq_check_inflight(), so
we don't need the local tmps for each function, I think)
> + struct bt_iter_data iter_data = {
> + .q = q,
> + .dio = &tmp,
> + };
> + struct bt_tags_iter_data tags_iter_data = {
> + .tags = tags,
> + .flags = flags,
> + .nr_reserved_tags = nr_resvd_tags,
> + .fn = mq_check_inflight,
> + .data = &iter_data,
> + };
> +
> + sbitmap_context_load(sbq + OFFSET(sbitmap_queue_sb), &sc);
> + sbitmap_for_each_set(&sc, bt_tags_iter, &tags_iter_data);
> +
> + dio->read = tmp.read;
> + dio->write = tmp.write;
> +}
> +
> +static void queue_for_each_hw_ctx(ulong q, ulong *hctx, uint cnt, struct diskio *dio)
> +{
> + uint i;
> + struct diskio tmp = {0};
This also can be removed.
> +
> + if (!hctx || !dio)
> + error(FATAL, "%s: Invalid parameter.\n", __func__);
This can be used?
> +
> + for (i = 0; i < cnt; i++) {
> + ulong addr = 0, tags = 0;
> + uint nr_reserved_tags = 0;
> +
> + if (!IS_KVADDR(hctx[i]))
> + continue;
Is this the remain of the v1 patch?
> +
> + /* Tags owned by the block driver */
> + addr = hctx[i] + OFFSET(blk_mq_hw_ctx_tags);
> + if (!readmem(addr, KVADDR, &tags, sizeof(ulong),
> + "blk_mq_hw_ctx.tags", RETURN_ON_ERROR))
> + break;
> +
> + addr = tags + OFFSET(blk_mq_tags_nr_reserved_tags);
> + if (!readmem(addr, KVADDR, &nr_reserved_tags, sizeof(uint),
> + "blk_mq_tags_nr_reserved_tags", RETURN_ON_ERROR))
> + break;
> +
> + if (nr_reserved_tags) {
> + addr = tags + OFFSET(blk_mq_tags_breserved_tags);
> + bt_tags_for_each(q, tags, addr, 1, nr_reserved_tags, &tmp);
> + }
> + addr = tags + OFFSET(blk_mq_tags_bitmap_tags);
> + bt_tags_for_each(q, tags, addr, 0, nr_reserved_tags, &tmp);
(the local tmp set by the nr_reserved_tags case is overwritten here.)
> + }
> +
> + dio->read = tmp.read;
> + dio->write = tmp.write;
> +}
> +
> +static void get_mq_diskio_from_hw_queues(ulong q, struct diskio *dio)
> +{
> + uint cnt = 0;
> + ulong addr = 0, hctx_addr = 0;
> + ulong *hctx_array = NULL;
> + struct diskio tmp = {0};
This also can be removed.
> +
> + addr = q + OFFSET(request_queue_nr_hw_queues);
> + readmem(addr, KVADDR, &cnt, sizeof(uint),
> + "request_queue.nr_hw_queues", FAULT_ON_ERROR);
> +
> + addr = q + OFFSET(request_queue_queue_hw_ctx);
> + readmem(addr, KVADDR, &hctx_addr, sizeof(void *),
> + "request_queue.queue_hw_ctx", FAULT_ON_ERROR);
> +
> + hctx_array = (ulong *)GETBUF(sizeof(void *) * cnt);
> + if (!hctx_array)
> + error(FATAL, "fail to get memory for the hctx_array\n");
> +
> + if (!readmem(hctx_addr, KVADDR, hctx_array, sizeof(void *) * cnt,
> + "request_queue.queue_hw_ctx[]", RETURN_ON_ERROR)) {
> + FREEBUF(hctx_array);
> + return;
> + }
> +
> + queue_for_each_hw_ctx(q, hctx_array, cnt, &tmp);
> + dio->read = tmp.read;
> + dio->write = tmp.write;
> +
> + FREEBUF(hctx_array);
> +}
> +
> static void
> get_mq_diskio(unsigned long q, unsigned long *mq_count)
> {
> int cpu;
> unsigned long queue_ctx;
> unsigned long mctx_addr;
> - struct diskio tmp;
> + struct diskio tmp = {0};
>
> if (INVALID_MEMBER(blk_mq_ctx_rq_dispatched) ||
> - INVALID_MEMBER(blk_mq_ctx_rq_completed))
> + INVALID_MEMBER(blk_mq_ctx_rq_completed)) {
> + get_mq_diskio_from_hw_queues(q, &tmp);
> + mq_count[0] = tmp.read;
> + mq_count[1] = tmp.write;
> return;
> -
> - memset(&tmp, 0x00, sizeof(struct diskio));
> + }
>
> readmem(q + OFFSET(request_queue_queue_ctx), KVADDR, &queue_ctx,
> sizeof(ulong), "request_queue.queue_ctx",
> @@ -4479,41 +4653,24 @@ display_one_diskio(struct iter *i, unsigned long gendisk, ulong flags)
> && (io.read + io.write == 0))
> return;
>
> - if (use_mq_interface(queue_addr) &&
> - (INVALID_MEMBER(blk_mq_ctx_rq_dispatched) ||
> - INVALID_MEMBER(blk_mq_ctx_rq_completed)))
> - fprintf(fp, "%s%s%s %s%s%s%s %s%s%s",
> - mkstring(buf0, 5, RJUST|INT_DEC, (char *)(unsigned long)major),
> - space(MINSPACE),
> - mkstring(buf1, VADDR_PRLEN, LJUST|LONG_HEX, (char *)gendisk),
> - space(MINSPACE),
> - mkstring(buf2, 10, LJUST, disk_name),
> - space(MINSPACE),
> - mkstring(buf3, VADDR_PRLEN <= 11 ? 11 : VADDR_PRLEN,
> - LJUST|LONG_HEX, (char *)queue_addr),
> - space(MINSPACE),
> - mkstring(buf4, 17, RJUST, "(not supported)"),
> - space(MINSPACE));
> -
> - else
> - fprintf(fp, "%s%s%s %s%s%s%s %s%5d%s%s%s%s%s",
> - mkstring(buf0, 5, RJUST|INT_DEC, (char *)(unsigned long)major),
> - space(MINSPACE),
> - mkstring(buf1, VADDR_PRLEN, LJUST|LONG_HEX, (char *)gendisk),
> - space(MINSPACE),
> - mkstring(buf2, 10, LJUST, disk_name),
> - space(MINSPACE),
> - mkstring(buf3, VADDR_PRLEN <= 11 ? 11 : VADDR_PRLEN,
> - LJUST|LONG_HEX, (char *)queue_addr),
> - space(MINSPACE),
> - io.read + io.write,
> - space(MINSPACE),
> - mkstring(buf4, 5, RJUST|INT_DEC,
> - (char *)(unsigned long)io.read),
> - space(MINSPACE),
> - mkstring(buf5, 5, RJUST|INT_DEC,
> - (char *)(unsigned long)io.write),
> - space(MINSPACE));
> + fprintf(fp, "%s%s%s %s%s%s%s %s%5d%s%s%s%s%s",
> + mkstring(buf0, 5, RJUST|INT_DEC, (char *)(unsigned long)major),
> + space(MINSPACE),
> + mkstring(buf1, VADDR_PRLEN, LJUST|LONG_HEX, (char *)gendisk),
> + space(MINSPACE),
> + mkstring(buf2, 10, LJUST, disk_name),
> + space(MINSPACE),
> + mkstring(buf3, VADDR_PRLEN <= 11 ? 11 : VADDR_PRLEN,
> + LJUST|LONG_HEX, (char *)queue_addr),
> + space(MINSPACE),
> + io.read + io.write,
> + space(MINSPACE),
> + mkstring(buf4, 5, RJUST|INT_DEC,
> + (char *)(unsigned long)io.read),
> + space(MINSPACE),
> + mkstring(buf5, 5, RJUST|INT_DEC,
> + (char *)(unsigned long)io.write),
> + space(MINSPACE));
>
> if (VALID_MEMBER(request_queue_in_flight)) {
> if (!use_mq_interface(queue_addr)) {
> @@ -4597,6 +4754,9 @@ void diskio_init(void)
> MEMBER_OFFSET_INIT(kobject_entry, "kobject", "entry");
> MEMBER_OFFSET_INIT(kset_list, "kset", "list");
> MEMBER_OFFSET_INIT(request_list_count, "request_list", "count");
> + MEMBER_OFFSET_INIT(request_cmd_flags, "request", "cmd_flags");
> + MEMBER_OFFSET_INIT(request_q, "request", "q");
> + MEMBER_OFFSET_INIT(request_state, "request", "state");
> MEMBER_OFFSET_INIT(request_queue_in_flight, "request_queue",
> "in_flight");
> if (MEMBER_EXISTS("request_queue", "rq"))
> @@ -4608,10 +4768,33 @@ void diskio_init(void)
> "mq_ops");
> ANON_MEMBER_OFFSET_INIT(request_queue_queue_ctx,
> "request_queue", "queue_ctx");
> + MEMBER_OFFSET_INIT(request_queue_queue_hw_ctx,
> + "request_queue", "queue_hw_ctx");
> + MEMBER_OFFSET_INIT(request_queue_nr_hw_queues,
> + "request_queue", "nr_hw_queues");
> MEMBER_OFFSET_INIT(blk_mq_ctx_rq_dispatched, "blk_mq_ctx",
> "rq_dispatched");
> MEMBER_OFFSET_INIT(blk_mq_ctx_rq_completed, "blk_mq_ctx",
> "rq_completed");
> + MEMBER_OFFSET_INIT(blk_mq_hw_ctx_tags, "blk_mq_hw_ctx", "tags");
> + MEMBER_OFFSET_INIT(blk_mq_tags_bitmap_tags, "blk_mq_tags",
> + "bitmap_tags");
> + MEMBER_OFFSET_INIT(blk_mq_tags_breserved_tags, "blk_mq_tags",
> + "breserved_tags");
> + MEMBER_OFFSET_INIT(blk_mq_tags_nr_reserved_tags, "blk_mq_tags",
> + "nr_reserved_tags");
> + MEMBER_OFFSET_INIT(blk_mq_tags_rqs, "blk_mq_tags", "rqs");
> + STRUCT_SIZE_INIT(blk_mq_tags, "blk_mq_tags");
> + STRUCT_SIZE_INIT(sbitmap, "sbitmap");
> + STRUCT_SIZE_INIT(sbitmap_word, "sbitmap_word");
> + MEMBER_OFFSET_INIT(sbitmap_word_word, "sbitmap_word", "word");
> + MEMBER_OFFSET_INIT(sbitmap_word_cleared, "sbitmap_word", "cleared");
> + MEMBER_OFFSET_INIT(sbitmap_depth, "sbitmap", "depth");
> + MEMBER_OFFSET_INIT(sbitmap_shift, "sbitmap", "shift");
> + MEMBER_OFFSET_INIT(sbitmap_map_nr, "sbitmap", "map_nr");
> + MEMBER_OFFSET_INIT(sbitmap_map, "sbitmap", "map");
> + MEMBER_OFFSET_INIT(sbitmap_queue_sb, "sbitmap_queue", "sb");
> +
> }
> MEMBER_OFFSET_INIT(subsys_private_klist_devices, "subsys_private",
> "klist_devices");
> diff --git a/symbols.c b/symbols.c
> index 5d12a021c769..c1f09556d710 100644
> --- a/symbols.c
> +++ b/symbols.c
> @@ -10385,6 +10385,12 @@ dump_offset_table(char *spec, ulong makestruct)
> OFFSET(kset_list));
> fprintf(fp, " request_list_count: %ld\n",
> OFFSET(request_list_count));
> + fprintf(fp, " request_cmd_flags: %ld\n",
> + OFFSET(request_cmd_flags));
> + fprintf(fp, " request_q: %ld\n",
> + OFFSET(request_q));
> + fprintf(fp, " request_state: %ld\n",
> + OFFSET(request_state));
> fprintf(fp, " request_queue_in_flight: %ld\n",
> OFFSET(request_queue_in_flight));
> fprintf(fp, " request_queue_rq: %ld\n",
> @@ -10393,10 +10399,25 @@ dump_offset_table(char *spec, ulong makestruct)
> OFFSET(request_queue_mq_ops));
> fprintf(fp, " request_queue_queue_ctx: %ld\n",
> OFFSET(request_queue_queue_ctx));
> + fprintf(fp, " request_queue_queue_hw_ctx: %ld\n",
> + OFFSET(request_queue_queue_hw_ctx));
> + fprintf(fp, " request_queue_nr_hw_queues: %ld\n",
> + OFFSET(request_queue_nr_hw_queues));
> fprintf(fp, " blk_mq_ctx_rq_dispatched: %ld\n",
> OFFSET(blk_mq_ctx_rq_dispatched));
> fprintf(fp, " blk_mq_ctx_rq_completed: %ld\n",
> OFFSET(blk_mq_ctx_rq_completed));
> + fprintf(fp, " blk_mq_hw_ctx_tags: %ld\n",
> + OFFSET(blk_mq_hw_ctx_tags));
> + fprintf(fp, " blk_mq_tags_bitmap_tags: %ld\n",
> + OFFSET(blk_mq_tags_bitmap_tags));
> + fprintf(fp, " blk_mq_tags_breserved_tags: %ld\n",
> + OFFSET(blk_mq_tags_breserved_tags));
> + fprintf(fp, " blk_mq_tags_nr_reserved_tags: %ld\n",
> + OFFSET(blk_mq_tags_nr_reserved_tags));
> + fprintf(fp, " blk_mq_tags_rqs: %ld\n",
> + OFFSET(blk_mq_tags_rqs));
Good, thanks for adjusting these indents.
Thanks,
Kazu
> +
> fprintf(fp, " subsys_private_klist_devices: %ld\n",
> OFFSET(subsys_private_klist_devices));
> fprintf(fp, " subsystem_kset: %ld\n",
> @@ -11003,6 +11024,7 @@ dump_offset_table(char *spec, ulong makestruct)
> fprintf(fp, " sbitmap: %ld\n", SIZE(sbitmap));
> fprintf(fp, " sbitmap_queue: %ld\n", SIZE(sbitmap_queue));
> fprintf(fp, " sbq_wait_state: %ld\n", SIZE(sbq_wait_state));
> + fprintf(fp, " blk_mq_tags: %ld\n", SIZE(blk_mq_tags));
>
> fprintf(fp, "\n array_table:\n");
> /*
--
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