On Thu, May 26, 2022 at 3:55 PM HAGIO KAZUHITO(萩尾 一仁) <[email protected]>
wrote:
> On 2022/05/23 19:06, Lianbo Jiang wrote:
> > Kernel commit 4e5cc99e1e48 ("blk-mq: manage hctx map via xarray") removed
> > the "queue_hw_ctx" member from struct request_queue at Linux v5.18-rc1,
> > and replaced it with a struct xarray "hctx_table".Without the patch,
>
> more complex...
>
Totally agree.
> the "dev -d|-D" options will print an error:
> >
> > crash> dev -d
> > MAJOR GENDISK NAME REQUEST_QUEUE TOTAL READ
> WRITE
> >
> > dev: invalid structure member offset: request_queue_queue_hw_ctx
> >
> > With the patch:
> > crash> dev -d
> > MAJOR GENDISK NAME REQUEST_QUEUE TOTAL READ
> WRITE
> > 8 ffff8e99d0a1ae00 sda ffff8e9c14c59980 10 6
> 4
> >
> > Signed-off-by: Lianbo Jiang <[email protected]>
> > ---
> > defs.h | 1 +
> > dev.c | 44 ++++++++++++++++++++++++++++++++++----------
> > symbols.c | 2 ++
> > 3 files changed, 37 insertions(+), 10 deletions(-)
> >
> > diff --git a/defs.h b/defs.h
> > index c1626bc79d59..1e435ffe5535 100644
> > --- a/defs.h
> > +++ b/defs.h
> > @@ -2181,6 +2181,7 @@ struct offset_table { /* stash
> of commonly-used offsets */
> > long blk_mq_tags_nr_reserved_tags;
> > long blk_mq_tags_rqs;
> > long blk_mq_tags_static_rqs;
> > + long request_queue_hctx_table;
> > };
> >
> > struct size_table { /* stash of commonly-used sizes */
> > diff --git a/dev.c b/dev.c
> > index 7e0b3d27888d..811414d93c94 100644
> > --- a/dev.c
> > +++ b/dev.c
> > @@ -4406,24 +4406,46 @@ 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 list_pair *lp = NULL;
> > struct diskio tmp = {0};
> >
> > - addr = q + OFFSET(request_queue_nr_hw_queues);
> > - readmem(addr, KVADDR, &cnt, sizeof(uint),
> > - "request_queue.nr_hw_queues", FAULT_ON_ERROR);
> > + if (MEMBER_EXISTS("request_queue", "hctx_table")) {
>
> As MEMBER_OFFSET_INIT() was done, we can use VALID_MEMBER() macro,
> which is faster than MEMBER_EXISTS(),
>
Right. Thanks.
Lianbo
>
> Thanks,
> Kazu
>
> > + addr = q + OFFSET(request_queue_hctx_table);
> > + cnt = do_xarray(addr, XARRAY_COUNT, NULL);
> > + lp = (struct list_pair *)GETBUF(sizeof(struct list_pair) *
> (cnt + 1));
> > + if (!lp)
> > + error(FATAL, "fail to get memory for
> list_pair.\n");
> > + lp[0].index = cnt;
> > + cnt = do_xarray(addr, XARRAY_GATHER, lp);
> > + } else {
> > + 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);
> > + 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)
> > + if (!hctx_array) {
> > + if (lp)
> > + FREEBUF(lp);
> > error(FATAL, "fail to get memory for the hctx_array\n");
> > + }
> > +
> > + if (lp && hctx_array) {
> > + uint i;
> >
> > - if (!readmem(hctx_addr, KVADDR, hctx_array, sizeof(void *) * cnt,
> > + /* copy it from list_pair to hctx_array */
> > + for (i = 0; i < cnt; i++) {
> > + hctx_array[i] = (ulong)lp[i].value;
> > + }
> > + FREEBUF(lp);
> > + } else if (!readmem(hctx_addr, KVADDR, hctx_array, sizeof(void *)
> * cnt,
> > "request_queue.queue_hw_ctx[]", RETURN_ON_ERROR)) {
> > - FREEBUF(hctx_array);
> > - return;
> > + FREEBUF(hctx_array);
> > + return;
> > }
> >
> > queue_for_each_hw_ctx(q, hctx_array, cnt, &tmp);
> > @@ -4796,6 +4818,8 @@ void diskio_init(void)
> > "request_queue", "queue_hw_ctx");
> > MEMBER_OFFSET_INIT(request_queue_nr_hw_queues,
> > "request_queue", "nr_hw_queues");
> > + MEMBER_OFFSET_INIT(request_queue_hctx_table,
> > + "request_queue", "hctx_table");
> > MEMBER_OFFSET_INIT(blk_mq_ctx_rq_dispatched, "blk_mq_ctx",
> > "rq_dispatched");
> > MEMBER_OFFSET_INIT(blk_mq_ctx_rq_completed, "blk_mq_ctx",
> > diff --git a/symbols.c b/symbols.c
> > index c432469671a4..cc439e8eb636 100644
> > --- a/symbols.c
> > +++ b/symbols.c
> > @@ -10401,6 +10401,8 @@ dump_offset_table(char *spec, ulong makestruct)
> > OFFSET(request_queue_queue_hw_ctx));
> > fprintf(fp, " request_queue_nr_hw_queues: %ld\n",
> > OFFSET(request_queue_nr_hw_queues));
> > + fprintf(fp, " request_queue_hctx_table: %ld\n",
> > + OFFSET(request_queue_hctx_table));
> > fprintf(fp, " blk_mq_ctx_rq_dispatched: %ld\n",
> > OFFSET(blk_mq_ctx_rq_dispatched));
> > fprintf(fp, " blk_mq_ctx_rq_completed: %ld\n",
--
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