On 2020-05-12 05:20, Weiping Zhang wrote:
> On Tue, May 12, 2020 at 8:09 PM Weiping Zhang <zwp10758@xxxxxxxxx> wrote:
>> I don't test block/030, since I don't pull blktest very often.
That's unfortunate ...
>> It's a different problem,
>> because the mapping cann't be reset when do fallback, so the
>> cpu[>=1] will point to a hctx(!=0).
>>
>> it should be fixed by:
>>
>> diff --git a/block/blk-mq.c b/block/blk-mq.c
>> index bc34d6b572b6..d82cefb0474f 100644
>> --- a/block/blk-mq.c
>> +++ b/block/blk-mq.c
>> @@ -3365,8 +3365,8 @@ static void __blk_mq_update_nr_hw_queues(struct
>> blk_mq_tag_set *set,
>> goto reregister;
>>
>> set->nr_hw_queues = nr_hw_queues;
>> - blk_mq_update_queue_map(set);
>> fallback:
>> + blk_mq_update_queue_map(set);
>> list_for_each_entry(q, &set->tag_list, tag_set_list) {
>> blk_mq_realloc_hw_ctxs(set, q);
>> if (q->nr_hw_queues != set->nr_hw_queues) {
If this is posted as a patch, feel free to add:
Tested-by: Bart van Assche <bvanassche@xxxxxxx>
> And block/030 should also be improved ?
>
> 35 # Since older null_blk versions do not allow "submit_queues" to be
> 36 # modified, check first whether that configs attribute is writeable.
> 37 # Each iteration of the loop below triggers $(nproc) + 1
> 38 # null_init_hctx() calls. Since <interval>=$(nproc), all possible
> 39 # blk_mq_realloc_hw_ctxs() error paths will be triggered. Whether or
> 40 # not this test succeeds depends on whether or not _check_dmesg()
> 41 # detects a kernel warning.
> 42 if { echo "$(<"$sq")" >$sq; } 2>/dev/null; then
> 43 for ((i = 0; i < 100; i++)); do
> 44 echo 1 > $sq
> 45 nproc > $sq # this line output lots
> "nproc: write error: Cannot allocate memory"
> 46 done
> 47 else
> 48 SKIP_REASON="Skipping test because $sq cannot be modified"
> 49 fi
>
>
> The test result show this test case [failed], actually it [pass],
> there is no warning detect
> in kernel log, if apply above patch.
>
> block/030 (trigger the blk_mq_realloc_hw_ctxs() error path) [failed]
> runtime 1.999s ... 2.115s
> --- tests/block/030.out 2020-05-12 10:42:26.345782849 +0800
> +++ /data1/zwp/src/blktests/results/nodev/block/030.out.bad
> 2020-05-12 20:14:59.878915218 +0800
> @@ -1 +1,51 @@
> +nproc: write error: Cannot allocate memory
> +nproc: write error: Cannot allocate memory
> +nproc: write error: Cannot allocate memory
> +nproc: write error: Cannot allocate memory
> +nproc: write error: Cannot allocate memory
> +nproc: write error: Cannot allocate memory
> +nproc: write error: Cannot allocate memory
> ...
> (Run 'diff -u tests/block/030.out
> /data1/zwp/src/blktests/results/nodev/block/030.out.bad' to see the
> entire diff)
That's weird. I have not yet encountered this. Test block/030 passes on
my setup.
Thanks,
Bart.
