By mistake, there is a '&' instead of a '==' in the definition of the
macro BFQQ_TOTALLY_SEEKY. This commit replaces the wrong operator with
the correct one.
Fixes: commit 7074f076ff15 ("block, bfq: do not tag totally seeky queues as soft rt")
Signed-off-by: Paolo Valente <[email protected]>
---
block/bfq-iosched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index f8d430f88d25..f9269ae6da9c 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -240,7 +240,7 @@ static struct kmem_cache *bfq_pool;
* containing only random (seeky) I/O are prevented from being tagged
* as soft real-time.
*/
-#define BFQQ_TOTALLY_SEEKY(bfqq) (bfqq->seek_history & -1)
+#define BFQQ_TOTALLY_SEEKY(bfqq) (bfqq->seek_history == -1)
/* Min number of samples required to perform peak-rate update */
#define BFQ_RATE_MIN_SAMPLES 32
--
2.20.1
On 6/22/19 2:44 PM, Paolo Valente wrote:
> By mistake, there is a '&' instead of a '==' in the definition of the
> macro BFQQ_TOTALLY_SEEKY. This commit replaces the wrong operator with
> the correct one.
A bit worrying that this wasn't caught in testing, as it would have
resulted in _any_ queue being positive for totally seeky?
Anyway, applied.
--
Jens Axboe
> Il giorno 24 giu 2019, alle ore 18:12, Jens Axboe <[email protected]> ha scritto:
>
> On 6/22/19 2:44 PM, Paolo Valente wrote:
>> By mistake, there is a '&' instead of a '==' in the definition of the
>> macro BFQQ_TOTALLY_SEEKY. This commit replaces the wrong operator with
>> the correct one.
>
> A bit worrying that this wasn't caught in testing, as it would have
> resulted in _any_ queue being positive for totally seeky?
>
Fortunately there's a somewhat reassuring explanation. The commit
introducing this macro prevented seeky queues from being considered
soft real-time. And, to be more selective, it actually filtered out
only totally seeky queues, i.e., queues whose last I/O requests are
*all* random. With this error, any seeky queue was considered totally
seeky. This the broke (only) selectivity.
> Anyway, applied.
>
Thanks,
Paolo
> --
> Jens Axboe
>