| Message ID | 20190622204416.33871-1-paolo.valente@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [BUGFIX,V2] block, bfq: fix operator in BFQQ_TOTALLY_SEEKY | expand |
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.
> Il giorno 24 giu 2019, alle ore 18:12, Jens Axboe <axboe@kernel.dk> 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 >
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
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 <paolo.valente@linaro.org> --- block/bfq-iosched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)