Hi Lianbo,
-----Original Message-----
> Kernel commit <9a14d6ce4135> ("block: remove debugfs blk_mq_ctx
> dispatched/merged/completed attributes") removed the member
> rq_dispatched and rq_completed from struct blk_mq_ctx. Without
> this patch, crash will fail with the following error:
>
> crash> dev -d
> MAJOR GENDISK NAME REQUEST_QUEUE TOTAL ASYNC SYNC
>
> dev: invalid structure member offset: blk_mq_ctx_rq_dispatched
> FILE: dev.c LINE: 4229 FUNCTION: get_one_mctx_diskio()
Thank you for working on this.
IIUC, crash will need sbitmap functionality to support this fully.
Meanwhile, I think it's OK to skip the count, but it should say "actually zero"
or "not supported" so that users can know it, for example:
crash> dev -d
MAJOR GENDISK NAME REQUEST_QUEUE TOTAL ASYNC SYNC
8 ffff92bbd102e400 sdb ffff92bbf04e3678 0 0 0
dev: sdb: Disk I/O statistics is not supported in this kernel
8 ffff92bbd1014400 sdc ffff92bbf04e26e8 0 0 0
dev: sdc: Disk I/O statistics is not supported in this kernel
11 ffff92c347da5e00 sr0 ffff92bbd9c3e528 0 0 0
253 ffff92bbca726e00 dm-0 ffff92bbcad7dd60 0 0 0
What do you think?
Thanks,
Kazu
>
> Signed-off-by: Lianbo Jiang <[email protected]>
> ---
> dev.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/dev.c b/dev.c
> index effe789f38d8..dd21511e5dfc 100644
> --- a/dev.c
> +++ b/dev.c
> @@ -4246,6 +4246,10 @@ get_mq_diskio(unsigned long q, unsigned long *mq_count)
> unsigned long mctx_addr;
> struct diskio tmp;
>
> + if (!MEMBER_EXISTS("blk_mq_ctx", "rq_dispatched") &&
> + !MEMBER_EXISTS("blk_mq_ctx", "rq_completed"))
> + return;
> +
> memset(&tmp, 0x00, sizeof(struct diskio));
>
> readmem(q + OFFSET(request_queue_queue_ctx), KVADDR, &queue_ctx,
> --
> 2.20.1
--
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