From: Yu Kuai <yukuai3@huawei.com>
Currently the nasty condition is wait_barrier() is hard to read. This
patch factor out the condition into a function.
There are no functional changes.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
drivers/md/raid10.c | 56 ++++++++++++++++++++++++++-------------------
1 file changed, 32 insertions(+), 24 deletions(-)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 64d6e4cd8a3a..56458a53043d 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -957,44 +957,52 @@ static void lower_barrier(struct r10conf *conf)
wake_up(&conf->wait_barrier);
}
+static bool stop_waiting_barrier(struct r10conf *conf)
+{
+ /* barrier is dropped */
+ if (!conf->barrier)
+ return true;
+
+ /*
+ * If there are already pending requests (preventing the barrier from
+ * rising completely), and the pre-process bio queue isn't empty, then
+ * don't wait, as we need to empty that queue to get the nr_pending
+ * count down.
+ */
+ if (atomic_read(&conf->nr_pending)) {
+ struct bio_list *bio_list = current->bio_list;
+
+ if (bio_list && (!bio_list_empty(&bio_list[0]) ||
+ !bio_list_empty(&bio_list[1])))
+ return true;
+ }
+
+ /* move on if recovery thread is blocked by us */
+ if (conf->mddev->thread->tsk == current &&
+ test_bit(MD_RECOVERY_RUNNING, &conf->mddev->recovery) &&
+ conf->nr_queued > 0)
+ return true;
+
+ return false;
+}
+
static bool wait_barrier(struct r10conf *conf, bool nowait)
{
bool ret = true;
spin_lock_irq(&conf->resync_lock);
if (conf->barrier) {
- struct bio_list *bio_list = current->bio_list;
- conf->nr_waiting++;
- /* Wait for the barrier to drop.
- * However if there are already pending
- * requests (preventing the barrier from
- * rising completely), and the
- * pre-process bio queue isn't empty,
- * then don't wait, as we need to empty
- * that queue to get the nr_pending
- * count down.
- */
/* Return false when nowait flag is set */
if (nowait) {
ret = false;
} else {
+ conf->nr_waiting++;
raid10_log(conf->mddev, "wait barrier");
wait_event_lock_irq(conf->wait_barrier,
- !conf->barrier ||
- (atomic_read(&conf->nr_pending) &&
- bio_list &&
- (!bio_list_empty(&bio_list[0]) ||
- !bio_list_empty(&bio_list[1]))) ||
- /* move on if recovery thread is
- * blocked by us
- */
- (conf->mddev->thread->tsk == current &&
- test_bit(MD_RECOVERY_RUNNING,
- &conf->mddev->recovery) &&
- conf->nr_queued > 0),
+ stop_waiting_barrier(conf),
conf->resync_lock);
+ conf->nr_waiting--;
}
- conf->nr_waiting--;
if (!conf->nr_waiting)
wake_up(&conf->wait_barrier);
}
--
2.31.1Dear Yu,
Thank you for the improved patch. Three minor nits.
Am 14.09.22 um 03:49 schrieb Yu Kuai:
> From: Yu Kuai <yukuai3@huawei.com>
In the summary/title, I’d spell *Clean up* with a space. Maybe even use:
md/raid10: Factor out code from wait_barrier() to stop_waiting_barrier()
> Currently the nasty condition is wait_barrier() is hard to read. This
> patch factor out the condition into a function.
The first *is* above can be removed, and factor*s* needs an s.
> There are no functional changes.
>
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
> ---
> drivers/md/raid10.c | 56 ++++++++++++++++++++++++++-------------------
> 1 file changed, 32 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 64d6e4cd8a3a..56458a53043d 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -957,44 +957,52 @@ static void lower_barrier(struct r10conf *conf)
> wake_up(&conf->wait_barrier);
> }
>
> +static bool stop_waiting_barrier(struct r10conf *conf)
> +{
> + /* barrier is dropped */
> + if (!conf->barrier)
> + return true;
> +
> + /*
> + * If there are already pending requests (preventing the barrier from
> + * rising completely), and the pre-process bio queue isn't empty, then
> + * don't wait, as we need to empty that queue to get the nr_pending
> + * count down.
> + */
> + if (atomic_read(&conf->nr_pending)) {
> + struct bio_list *bio_list = current->bio_list;
> +
> + if (bio_list && (!bio_list_empty(&bio_list[0]) ||
> + !bio_list_empty(&bio_list[1])))
> + return true;
> + }
> +
> + /* move on if recovery thread is blocked by us */
> + if (conf->mddev->thread->tsk == current &&
> + test_bit(MD_RECOVERY_RUNNING, &conf->mddev->recovery) &&
> + conf->nr_queued > 0)
> + return true;
> +
> + return false;
> +}
> +
> static bool wait_barrier(struct r10conf *conf, bool nowait)
> {
> bool ret = true;
>
> spin_lock_irq(&conf->resync_lock);
> if (conf->barrier) {
> - struct bio_list *bio_list = current->bio_list;
> - conf->nr_waiting++;
> - /* Wait for the barrier to drop.
> - * However if there are already pending
> - * requests (preventing the barrier from
> - * rising completely), and the
> - * pre-process bio queue isn't empty,
> - * then don't wait, as we need to empty
> - * that queue to get the nr_pending
> - * count down.
> - */
> /* Return false when nowait flag is set */
> if (nowait) {
> ret = false;
> } else {
> + conf->nr_waiting++;
> raid10_log(conf->mddev, "wait barrier");
> wait_event_lock_irq(conf->wait_barrier,
> - !conf->barrier ||
> - (atomic_read(&conf->nr_pending) &&
> - bio_list &&
> - (!bio_list_empty(&bio_list[0]) ||
> - !bio_list_empty(&bio_list[1]))) ||
> - /* move on if recovery thread is
> - * blocked by us
> - */
> - (conf->mddev->thread->tsk == current &&
> - test_bit(MD_RECOVERY_RUNNING,
> - &conf->mddev->recovery) &&
> - conf->nr_queued > 0),
> + stop_waiting_barrier(conf),
> conf->resync_lock);
> + conf->nr_waiting--;
> }
> - conf->nr_waiting--;
> if (!conf->nr_waiting)
> wake_up(&conf->wait_barrier);
> }
Acked-by: Paul Menzel <pmenzel@molgen.mpg.de>
Kind regards,
Paul
Hi, Paul
在 2022/09/14 14:36, Paul Menzel 写道:
> Dear Yu,
>
>
> Thank you for the improved patch. Three minor nits.
>
> Am 14.09.22 um 03:49 schrieb Yu Kuai:
>> From: Yu Kuai <yukuai3@huawei.com>
>
> In the summary/title, I’d spell *Clean up* with a space. Maybe even use:
>
> md/raid10: Factor out code from wait_barrier() to stop_waiting_barrier()
Ok, sounds good, I'll change that in next version.
>
>> Currently the nasty condition is wait_barrier() is hard to read. This
>> patch factor out the condition into a function.
>
> The first *is* above can be removed, and factor*s* needs an s.
Yes, you're right.
>> There are no functional changes.
>>
>> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
>> ---
>> drivers/md/raid10.c | 56 ++++++++++++++++++++++++++-------------------
>> 1 file changed, 32 insertions(+), 24 deletions(-)
>>
>> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
>> index 64d6e4cd8a3a..56458a53043d 100644
>> --- a/drivers/md/raid10.c
>> +++ b/drivers/md/raid10.c
>> @@ -957,44 +957,52 @@ static void lower_barrier(struct r10conf *conf)
>> wake_up(&conf->wait_barrier);
>> }
>> +static bool stop_waiting_barrier(struct r10conf *conf)
>> +{
>> + /* barrier is dropped */
>> + if (!conf->barrier)
>> + return true;
>> +
>> + /*
>> + * If there are already pending requests (preventing the barrier
>> from
>> + * rising completely), and the pre-process bio queue isn't empty,
>> then
>> + * don't wait, as we need to empty that queue to get the nr_pending
>> + * count down.
>> + */
>> + if (atomic_read(&conf->nr_pending)) {
>> + struct bio_list *bio_list = current->bio_list;
>> +
>> + if (bio_list && (!bio_list_empty(&bio_list[0]) ||
>> + !bio_list_empty(&bio_list[1])))
>> + return true;
>> + }
>> +
>> + /* move on if recovery thread is blocked by us */
>> + if (conf->mddev->thread->tsk == current &&
>> + test_bit(MD_RECOVERY_RUNNING, &conf->mddev->recovery) &&
>> + conf->nr_queued > 0)
>> + return true;
>> +
>> + return false;
>> +}
>> +
>> static bool wait_barrier(struct r10conf *conf, bool nowait)
>> {
>> bool ret = true;
>> spin_lock_irq(&conf->resync_lock);
>> if (conf->barrier) {
>> - struct bio_list *bio_list = current->bio_list;
>> - conf->nr_waiting++;
>> - /* Wait for the barrier to drop.
>> - * However if there are already pending
>> - * requests (preventing the barrier from
>> - * rising completely), and the
>> - * pre-process bio queue isn't empty,
>> - * then don't wait, as we need to empty
>> - * that queue to get the nr_pending
>> - * count down.
>> - */
>> /* Return false when nowait flag is set */
>> if (nowait) {
>> ret = false;
>> } else {
>> + conf->nr_waiting++;
>> raid10_log(conf->mddev, "wait barrier");
>> wait_event_lock_irq(conf->wait_barrier,
>> - !conf->barrier ||
>> - (atomic_read(&conf->nr_pending) &&
>> - bio_list &&
>> - (!bio_list_empty(&bio_list[0]) ||
>> - !bio_list_empty(&bio_list[1]))) ||
>> - /* move on if recovery thread is
>> - * blocked by us
>> - */
>> - (conf->mddev->thread->tsk == current &&
>> - test_bit(MD_RECOVERY_RUNNING,
>> - &conf->mddev->recovery) &&
>> - conf->nr_queued > 0),
>> + stop_waiting_barrier(conf),
>> conf->resync_lock);
>> + conf->nr_waiting--;
>> }
>> - conf->nr_waiting--;
>> if (!conf->nr_waiting)
>> wake_up(&conf->wait_barrier);
>> }
>
> Acked-by: Paul Menzel <pmenzel@molgen.mpg.de>
Thanks,
Kuai
>
>
> Kind regards,
>
> Paul
>
> .
>
On 2022-09-13 19:49, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@huawei.com>
>
> Currently the nasty condition is wait_barrier() is hard to read. This
> patch factor out the condition into a function.
>
> There are no functional changes.
>
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
> ---
> drivers/md/raid10.c | 56 ++++++++++++++++++++++++++-------------------
> 1 file changed, 32 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 64d6e4cd8a3a..56458a53043d 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -957,44 +957,52 @@ static void lower_barrier(struct r10conf *conf)
> wake_up(&conf->wait_barrier);
> }
>
> +static bool stop_waiting_barrier(struct r10conf *conf)
> +{
> + /* barrier is dropped */
> + if (!conf->barrier)
> + return true;
> +
> + /*
> + * If there are already pending requests (preventing the barrier from
> + * rising completely), and the pre-process bio queue isn't empty, then
> + * don't wait, as we need to empty that queue to get the nr_pending
> + * count down.
> + */
> + if (atomic_read(&conf->nr_pending)) {
> + struct bio_list *bio_list = current->bio_list;
I'd probably just put the bio_list declaration at the top of this
function, then the nested if statements are not necessary. The compiler
should be able to optimize the access just fine.
> if (conf->barrier) {
> - struct bio_list *bio_list = current->bio_list;
> - conf->nr_waiting++;
> - /* Wait for the barrier to drop.
> - * However if there are already pending
> - * requests (preventing the barrier from
> - * rising completely), and the
> - * pre-process bio queue isn't empty,
> - * then don't wait, as we need to empty
> - * that queue to get the nr_pending
> - * count down.
> - */
> /* Return false when nowait flag is set */
> if (nowait) {
> ret = false;
> } else {
> + conf->nr_waiting++;
Technically speaking, I think moving nr_waiting counts as a functional
change. As best as I can see it is correct, but it should probably be at
least mentioned in the commit message, or maybe done as a separate
commit with it's own justification. That way if it causes problems down
the road, a bisect will make the issue clearer.
Thanks,
Logan
Hi,
在 2022/09/15 0:16, Logan Gunthorpe 写道:
>
>
> On 2022-09-13 19:49, Yu Kuai wrote:
>> From: Yu Kuai <yukuai3@huawei.com>
>>
>> Currently the nasty condition is wait_barrier() is hard to read. This
>> patch factor out the condition into a function.
>>
>> There are no functional changes.
>>
>> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
>> ---
>> drivers/md/raid10.c | 56 ++++++++++++++++++++++++++-------------------
>> 1 file changed, 32 insertions(+), 24 deletions(-)
>>
>> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
>> index 64d6e4cd8a3a..56458a53043d 100644
>> --- a/drivers/md/raid10.c
>> +++ b/drivers/md/raid10.c
>> @@ -957,44 +957,52 @@ static void lower_barrier(struct r10conf *conf)
>> wake_up(&conf->wait_barrier);
>> }
>>
>> +static bool stop_waiting_barrier(struct r10conf *conf)
>> +{
>> + /* barrier is dropped */
>> + if (!conf->barrier)
>> + return true;
>> +
>> + /*
>> + * If there are already pending requests (preventing the barrier from
>> + * rising completely), and the pre-process bio queue isn't empty, then
>> + * don't wait, as we need to empty that queue to get the nr_pending
>> + * count down.
>> + */
>> + if (atomic_read(&conf->nr_pending)) {
>> + struct bio_list *bio_list = current->bio_list;
>
> I'd probably just put the bio_list declaration at the top of this
> function, then the nested if statements are not necessary. The compiler
> should be able to optimize the access just fine.
>
>> if (conf->barrier) {
>> - struct bio_list *bio_list = current->bio_list;
>> - conf->nr_waiting++;
>> - /* Wait for the barrier to drop.
>> - * However if there are already pending
>> - * requests (preventing the barrier from
>> - * rising completely), and the
>> - * pre-process bio queue isn't empty,
>> - * then don't wait, as we need to empty
>> - * that queue to get the nr_pending
>> - * count down.
>> - */
>> /* Return false when nowait flag is set */
>> if (nowait) {
>> ret = false;
>> } else {
>> + conf->nr_waiting++;
>
> Technically speaking, I think moving nr_waiting counts as a functional
> change. As best as I can see it is correct, but it should probably be at
> least mentioned in the commit message, or maybe done as a separate
> commit with it's own justification. That way if it causes problems down
> the road, a bisect will make the issue clearer.
Thanks for your advice, I just think increase and decrease nr_waiting in
the case 'nowait' is pointless, and I move it incidentally.
I'll post a separate clean up patch to do that.
Paul, can I still add your Acked-by for this patch?
Thanks,
Kuai
>
> Thanks,
>
> Logan
> .
>
Dear Yu,
Am 15.09.22 um 09:21 schrieb Yu Kuai:
> 在 2022/09/15 0:16, Logan Gunthorpe 写道:
>> On 2022-09-13 19:49, Yu Kuai wrote:
>>> From: Yu Kuai <yukuai3@huawei.com>
>>>
>>> Currently the nasty condition is wait_barrier() is hard to read. This
>>> patch factor out the condition into a function.
>>>
>>> There are no functional changes.
>>>
>>> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
>>> ---
>>> drivers/md/raid10.c | 56 ++++++++++++++++++++++++++-------------------
>>> 1 file changed, 32 insertions(+), 24 deletions(-)
>>>
>>> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
>>> index 64d6e4cd8a3a..56458a53043d 100644
>>> --- a/drivers/md/raid10.c
>>> +++ b/drivers/md/raid10.c
>>> @@ -957,44 +957,52 @@ static void lower_barrier(struct r10conf *conf)
>>> wake_up(&conf->wait_barrier);
>>> }
>>> +static bool stop_waiting_barrier(struct r10conf *conf)
>>> +{
>>> + /* barrier is dropped */
>>> + if (!conf->barrier)
>>> + return true;
>>> +
>>> + /*
>>> + * If there are already pending requests (preventing the barrier
>>> from
>>> + * rising completely), and the pre-process bio queue isn't
>>> empty, then
>>> + * don't wait, as we need to empty that queue to get the nr_pending
>>> + * count down.
>>> + */
>>> + if (atomic_read(&conf->nr_pending)) {
>>> + struct bio_list *bio_list = current->bio_list;
>>
>> I'd probably just put the bio_list declaration at the top of this
>> function, then the nested if statements are not necessary. The compiler
>> should be able to optimize the access just fine.
>>
>>> if (conf->barrier) {
>>> - struct bio_list *bio_list = current->bio_list;
>>> - conf->nr_waiting++;
>>> - /* Wait for the barrier to drop.
>>> - * However if there are already pending
>>> - * requests (preventing the barrier from
>>> - * rising completely), and the
>>> - * pre-process bio queue isn't empty,
>>> - * then don't wait, as we need to empty
>>> - * that queue to get the nr_pending
>>> - * count down.
>>> - */
>>> /* Return false when nowait flag is set */
>>> if (nowait) {
>>> ret = false;
>>> } else {
>>> + conf->nr_waiting++;
>>
>> Technically speaking, I think moving nr_waiting counts as a functional
>> change. As best as I can see it is correct, but it should probably be at
>> least mentioned in the commit message, or maybe done as a separate
>> commit with it's own justification. That way if it causes problems down
>> the road, a bisect will make the issue clearer.
>
> Thanks for your advice, I just think increase and decrease nr_waiting in
> the case 'nowait' is pointless, and I move it incidentally.
>
> I'll post a separate clean up patch to do that.
>
> Paul, can I still add your Acked-by for this patch?
Yes, sure.
Kind regards,
Paul
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