* [PATCH] block: increase BLKCG_MAX_POLS
@ 2021-07-17 12:33 Oleksandr Natalenko
2021-07-17 19:07 ` Jens Axboe
0 siblings, 1 reply; 2+ messages in thread
From: Oleksandr Natalenko @ 2021-07-17 12:33 UTC (permalink / raw)
To: linux-kernel
Cc: linux-block, Jens Axboe, Ming Lei, Christoph Hellwig,
Laurence Oberman, Paolo Valente, David Jeffery, Bart Van Assche
After mq-deadline learnt to deal with cgroups, the BLKCG_MAX_POLS value
became too small for all the elevators to be registered properly. The
following issue is seen:
```
calling bfq_init+0x0/0x8b @ 1
blkcg_policy_register: BLKCG_MAX_POLS too small
initcall bfq_init+0x0/0x8b returned -28 after 507 usecs
```
and BFQ is non-functional.
Increase BLKCG_MAX_POLS to allow space for everyone
Link: https://lore.kernel.org/lkml/8988303.mDXGIdCtx8@natalenko.name/
Signed-off-by: Oleksandr Natalenko <oleksandr@natalenko.name>
---
include/linux/blkdev.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 3177181c4326..d3afea47ade6 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -57,7 +57,7 @@ struct blk_keyslot_manager;
* Maximum number of blkcg policies allowed to be registered concurrently.
* Defined here to simplify include dependency.
*/
-#define BLKCG_MAX_POLS 5
+#define BLKCG_MAX_POLS 6
typedef void (rq_end_io_fn)(struct request *, blk_status_t);
--
2.32.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] block: increase BLKCG_MAX_POLS
2021-07-17 12:33 [PATCH] block: increase BLKCG_MAX_POLS Oleksandr Natalenko
@ 2021-07-17 19:07 ` Jens Axboe
0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2021-07-17 19:07 UTC (permalink / raw)
To: Oleksandr Natalenko, linux-kernel
Cc: linux-block, Ming Lei, Christoph Hellwig, Laurence Oberman,
Paolo Valente, David Jeffery, Bart Van Assche
On 7/17/21 6:33 AM, Oleksandr Natalenko wrote:
> After mq-deadline learnt to deal with cgroups, the BLKCG_MAX_POLS value
> became too small for all the elevators to be registered properly. The
> following issue is seen:
>
> ```
> calling bfq_init+0x0/0x8b @ 1
> blkcg_policy_register: BLKCG_MAX_POLS too small
> initcall bfq_init+0x0/0x8b returned -28 after 507 usecs
> ```
>
> and BFQ is non-functional.
>
> Increase BLKCG_MAX_POLS to allow space for everyone
LGTM, just needs a:
Fixes: 08a9ad8bf607 ("block/mq-deadline: Add cgroup support")
in there too, I'll add it.
--
Jens Axboe
^ permalink raw reply [flat|nested] 2+ messages in thread
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