| Message ID | 20240108190113.1264200-3-axboe@kernel.dk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Optimize get_current_ioprio() a bit | expand |
On 1/8/24 10:59, Jens Axboe wrote: > We don't need to do any gymnastics if we don't have an io_context > assigned at all, so just return early with our default priority. > > Signed-off-by: Jens Axboe <axboe@kernel.dk> > --- > include/linux/ioprio.h | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/include/linux/ioprio.h b/include/linux/ioprio.h > index d6a9b5b7ed16..db1249cd9692 100644 > --- a/include/linux/ioprio.h > +++ b/include/linux/ioprio.h > @@ -59,13 +59,13 @@ static inline int __get_task_ioprio(struct task_struct *p) > struct io_context *ioc = p->io_context; > int prio; > > + if (!ioc) > + return IOPRIO_DEFAULT; > + > if (p != current) > lockdep_assert_held(&p->alloc_lock); > - if (ioc) > - prio = ioc->ioprio; > - else > - prio = IOPRIO_DEFAULT; > > + prio = ioc->ioprio; > if (IOPRIO_PRIO_CLASS(prio) == IOPRIO_CLASS_NONE) > prio = IOPRIO_PRIO_VALUE(task_nice_ioclass(p), > task_nice_ioprio(p)); Shouldn't it be mentioned in the subject that this patch is a performance optimization? Anyway: Reviewed-by: Bart Van Assche <bvanassche@acm.org>
On 1/8/24 12:22 PM, Bart Van Assche wrote: > On 1/8/24 10:59, Jens Axboe wrote: >> We don't need to do any gymnastics if we don't have an io_context >> assigned at all, so just return early with our default priority. >> >> Signed-off-by: Jens Axboe <axboe@kernel.dk> >> --- >> include/linux/ioprio.h | 8 ++++---- >> 1 file changed, 4 insertions(+), 4 deletions(-) >> >> diff --git a/include/linux/ioprio.h b/include/linux/ioprio.h >> index d6a9b5b7ed16..db1249cd9692 100644 >> --- a/include/linux/ioprio.h >> +++ b/include/linux/ioprio.h >> @@ -59,13 +59,13 @@ static inline int __get_task_ioprio(struct task_struct *p) >> struct io_context *ioc = p->io_context; >> int prio; >> + if (!ioc) >> + return IOPRIO_DEFAULT; >> + >> if (p != current) >> lockdep_assert_held(&p->alloc_lock); >> - if (ioc) >> - prio = ioc->ioprio; >> - else >> - prio = IOPRIO_DEFAULT; >> + prio = ioc->ioprio; >> if (IOPRIO_PRIO_CLASS(prio) == IOPRIO_CLASS_NONE) >> prio = IOPRIO_PRIO_VALUE(task_nice_ioclass(p), >> task_nice_ioprio(p)); > > Shouldn't it be mentioned in the subject that this patch is a performance > optimization? Anyway: I doubt this matters for performance really, it's more of a readability thing for me. > Reviewed-by: Bart Van Assche <bvanassche@acm.org> Thanks!
On 1/8/24 10:59, Jens Axboe wrote: > We don't need to do any gymnastics if we don't have an io_context > assigned at all, so just return early with our default priority. > > Signed-off-by: Jens Axboe <axboe@kernel.dk> > --- > Looks good. Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> -ck
diff --git a/include/linux/ioprio.h b/include/linux/ioprio.h index d6a9b5b7ed16..db1249cd9692 100644 --- a/include/linux/ioprio.h +++ b/include/linux/ioprio.h @@ -59,13 +59,13 @@ static inline int __get_task_ioprio(struct task_struct *p) struct io_context *ioc = p->io_context; int prio; + if (!ioc) + return IOPRIO_DEFAULT; + if (p != current) lockdep_assert_held(&p->alloc_lock); - if (ioc) - prio = ioc->ioprio; - else - prio = IOPRIO_DEFAULT; + prio = ioc->ioprio; if (IOPRIO_PRIO_CLASS(prio) == IOPRIO_CLASS_NONE) prio = IOPRIO_PRIO_VALUE(task_nice_ioclass(p), task_nice_ioprio(p));
We don't need to do any gymnastics if we don't have an io_context assigned at all, so just return early with our default priority. Signed-off-by: Jens Axboe <axboe@kernel.dk> --- include/linux/ioprio.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)