* [PATCH io_uring-5.14 v2] io_uring: remove double poll wait entry for pure poll
@ 2021-07-23 9:22 Hao Xu
2021-07-23 14:31 ` Pavel Begunkov
0 siblings, 1 reply; 8+ messages in thread
From: Hao Xu @ 2021-07-23 9:22 UTC (permalink / raw)
To: Jens Axboe; +Cc: io-uring, Pavel Begunkov, Joseph Qi
For pure poll requests, we should remove the double poll wait entry.
And io_poll_remove_double() is good enough for it compared with
io_poll_remove_waitqs().
Signed-off-by: Hao Xu <[email protected]>
---
v1-->v2
delete redundant io_poll_remove_double()
fs/io_uring.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index f2fe4eca150b..c5fe8b9e26b4 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4903,7 +4903,6 @@ static bool io_poll_complete(struct io_kiocb *req, __poll_t mask)
if (req->poll.events & EPOLLONESHOT)
flags = 0;
if (!io_cqring_fill_event(ctx, req->user_data, error, flags)) {
- io_poll_remove_waitqs(req);
req->poll.done = true;
flags = 0;
}
@@ -4926,6 +4925,7 @@ static void io_poll_task_func(struct io_kiocb *req)
done = io_poll_complete(req, req->result);
if (done) {
+ io_poll_remove_double(req);
hash_del(&req->hash_node);
} else {
req->result = 0;
@@ -5113,7 +5113,7 @@ static __poll_t __io_arm_poll_handler(struct io_kiocb *req,
ipt->error = -EINVAL;
spin_lock_irq(&ctx->completion_lock);
- if (ipt->error)
+ if (ipt->error || (mask && (poll->events & EPOLLONESHOT)))
io_poll_remove_double(req);
if (likely(poll->head)) {
spin_lock(&poll->head->lock);
@@ -5185,7 +5185,6 @@ static int io_arm_poll_handler(struct io_kiocb *req)
ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask,
io_async_wake);
if (ret || ipt.error) {
- io_poll_remove_double(req);
spin_unlock_irq(&ctx->completion_lock);
if (ret)
return IO_APOLL_READY;
--
2.24.4
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH io_uring-5.14 v2] io_uring: remove double poll wait entry for pure poll
2021-07-23 9:22 [PATCH io_uring-5.14 v2] io_uring: remove double poll wait entry for pure poll Hao Xu
@ 2021-07-23 14:31 ` Pavel Begunkov
2021-07-23 16:22 ` Jens Axboe
2021-07-24 4:48 ` Hao Xu
0 siblings, 2 replies; 8+ messages in thread
From: Pavel Begunkov @ 2021-07-23 14:31 UTC (permalink / raw)
To: Hao Xu, Jens Axboe; +Cc: io-uring, Joseph Qi
On 7/23/21 10:22 AM, Hao Xu wrote:
> For pure poll requests, we should remove the double poll wait entry.
> And io_poll_remove_double() is good enough for it compared with
> io_poll_remove_waitqs().
5.14 in the subject hints me that it's a fix. Is it?
Can you add what it fixes or expand on why it's better?
> Signed-off-by: Hao Xu <[email protected]>
> ---
>
> v1-->v2
> delete redundant io_poll_remove_double()
>
> fs/io_uring.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index f2fe4eca150b..c5fe8b9e26b4 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -4903,7 +4903,6 @@ static bool io_poll_complete(struct io_kiocb *req, __poll_t mask)
> if (req->poll.events & EPOLLONESHOT)
> flags = 0;
> if (!io_cqring_fill_event(ctx, req->user_data, error, flags)) {
> - io_poll_remove_waitqs(req);
> req->poll.done = true;
> flags = 0;
> }
> @@ -4926,6 +4925,7 @@ static void io_poll_task_func(struct io_kiocb *req)
>
> done = io_poll_complete(req, req->result);
> if (done) {
> + io_poll_remove_double(req);
> hash_del(&req->hash_node);
> } else {
> req->result = 0;
> @@ -5113,7 +5113,7 @@ static __poll_t __io_arm_poll_handler(struct io_kiocb *req,
> ipt->error = -EINVAL;
>
> spin_lock_irq(&ctx->completion_lock);
> - if (ipt->error)
> + if (ipt->error || (mask && (poll->events & EPOLLONESHOT)))
> io_poll_remove_double(req);
> if (likely(poll->head)) {
> spin_lock(&poll->head->lock);
> @@ -5185,7 +5185,6 @@ static int io_arm_poll_handler(struct io_kiocb *req)
> ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask,
> io_async_wake);
> if (ret || ipt.error) {
> - io_poll_remove_double(req);
> spin_unlock_irq(&ctx->completion_lock);
> if (ret)
> return IO_APOLL_READY;
>
--
Pavel Begunkov
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH io_uring-5.14 v2] io_uring: remove double poll wait entry for pure poll
2021-07-23 14:31 ` Pavel Begunkov
@ 2021-07-23 16:22 ` Jens Axboe
2021-07-24 4:48 ` Hao Xu
1 sibling, 0 replies; 8+ messages in thread
From: Jens Axboe @ 2021-07-23 16:22 UTC (permalink / raw)
To: Pavel Begunkov, Hao Xu; +Cc: io-uring, Joseph Qi
On 7/23/21 8:31 AM, Pavel Begunkov wrote:
> On 7/23/21 10:22 AM, Hao Xu wrote:
>> For pure poll requests, we should remove the double poll wait entry.
>> And io_poll_remove_double() is good enough for it compared with
>> io_poll_remove_waitqs().
>
> 5.14 in the subject hints me that it's a fix. Is it?
> Can you add what it fixes or expand on why it's better?
Ditto that, the commit message explains what is being done, it should
explain _why_ it's being done. For the 'what' part you can read the
code. So while the patch doesn't look wrong, I also can't quite tell why
the change is necessary.
--
Jens Axboe
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH io_uring-5.14 v2] io_uring: remove double poll wait entry for pure poll
2021-07-23 14:31 ` Pavel Begunkov
2021-07-23 16:22 ` Jens Axboe
@ 2021-07-24 4:48 ` Hao Xu
2021-07-26 12:40 ` Pavel Begunkov
1 sibling, 1 reply; 8+ messages in thread
From: Hao Xu @ 2021-07-24 4:48 UTC (permalink / raw)
To: Pavel Begunkov, Jens Axboe; +Cc: io-uring, Joseph Qi
在 2021/7/23 下午10:31, Pavel Begunkov 写道:
> On 7/23/21 10:22 AM, Hao Xu wrote:
>> For pure poll requests, we should remove the double poll wait entry.
>> And io_poll_remove_double() is good enough for it compared with
>> io_poll_remove_waitqs().
>
> 5.14 in the subject hints me that it's a fix. Is it?
> Can you add what it fixes or expand on why it's better?
Hi Pavel, I found that for poll_add() requests, it doesn't remove the
double poll wait entry when it's done, neither after vfs_poll() or in
the poll completion handler. The patch is mainly to fix it.
>
>
>> Signed-off-by: Hao Xu <[email protected]>
>> ---
>>
>> v1-->v2
>> delete redundant io_poll_remove_double()
>>
>> fs/io_uring.c | 5 ++---
>> 1 file changed, 2 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>> index f2fe4eca150b..c5fe8b9e26b4 100644
>> --- a/fs/io_uring.c
>> +++ b/fs/io_uring.c
>> @@ -4903,7 +4903,6 @@ static bool io_poll_complete(struct io_kiocb *req, __poll_t mask)
>> if (req->poll.events & EPOLLONESHOT)
>> flags = 0;
>> if (!io_cqring_fill_event(ctx, req->user_data, error, flags)) {
>> - io_poll_remove_waitqs(req);
Currently I only see it does that with io_poll_remove_waitqs() when
cqring overflow and then ocqe allocation failed. Using
io_poll_remove_waitqs() here is not very suitable since (1) it calls
__io_poll_remove_one() which set poll->cancelled = true, why do we set
poll->cancelled and poll->done to true at the same time though I think
that doesn't cause any problem. (2) it does
list_del_init(&poll->wait.entry) and hash_del(&req->hash_node) which
has been already done.
Correct me if I'm wrong since I may misunderstand the code.
Regards,
Hao
>> req->poll.done = true;
>> flags = 0;
>> }
>> @@ -4926,6 +4925,7 @@ static void io_poll_task_func(struct io_kiocb *req)
>>
>> done = io_poll_complete(req, req->result);
>> if (done) {
>> + io_poll_remove_double(req);
>> hash_del(&req->hash_node);
>> } else {
>> req->result = 0;
>> @@ -5113,7 +5113,7 @@ static __poll_t __io_arm_poll_handler(struct io_kiocb *req,
>> ipt->error = -EINVAL;
>>
>> spin_lock_irq(&ctx->completion_lock);
>> - if (ipt->error)
>> + if (ipt->error || (mask && (poll->events & EPOLLONESHOT)))
>> io_poll_remove_double(req);
>> if (likely(poll->head)) {
>> spin_lock(&poll->head->lock);
>> @@ -5185,7 +5185,6 @@ static int io_arm_poll_handler(struct io_kiocb *req)
>> ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask,
>> io_async_wake);
>> if (ret || ipt.error) {
>> - io_poll_remove_double(req);
>> spin_unlock_irq(&ctx->completion_lock);
>> if (ret)
>> return IO_APOLL_READY;
>>
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH io_uring-5.14 v2] io_uring: remove double poll wait entry for pure poll
2021-07-24 4:48 ` Hao Xu
@ 2021-07-26 12:40 ` Pavel Begunkov
2021-07-26 14:39 ` Hao Xu
0 siblings, 1 reply; 8+ messages in thread
From: Pavel Begunkov @ 2021-07-26 12:40 UTC (permalink / raw)
To: Hao Xu, Jens Axboe; +Cc: io-uring, Joseph Qi
On 7/24/21 5:48 AM, Hao Xu wrote:
> 在 2021/7/23 下午10:31, Pavel Begunkov 写道:
>> On 7/23/21 10:22 AM, Hao Xu wrote:
>>> For pure poll requests, we should remove the double poll wait entry.
>>> And io_poll_remove_double() is good enough for it compared with
>>> io_poll_remove_waitqs().
>>
>> 5.14 in the subject hints me that it's a fix. Is it?
>> Can you add what it fixes or expand on why it's better?
> Hi Pavel, I found that for poll_add() requests, it doesn't remove the
> double poll wait entry when it's done, neither after vfs_poll() or in
> the poll completion handler. The patch is mainly to fix it.
Ok, sounds good. Please resend with updated description, and
let's add some tags.
Fixes: 88e41cf928a6 ("io_uring: add multishot mode for IORING_OP_POLL_ADD")
Cc: [email protected] # 5.13+
Also, I'd prefer the commit title to make more clear that it's a
fix. E.g. "io_uring: fix poll requests leaking second poll entries".
Btw, seems it should fix hangs in ./poll-mshot-update
>>
>>> Signed-off-by: Hao Xu <[email protected]>
>>> ---
>>>
>>> v1-->v2
>>> delete redundant io_poll_remove_double()
>>>
>>> fs/io_uring.c | 5 ++---
>>> 1 file changed, 2 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>>> index f2fe4eca150b..c5fe8b9e26b4 100644
>>> --- a/fs/io_uring.c
>>> +++ b/fs/io_uring.c
>>> @@ -4903,7 +4903,6 @@ static bool io_poll_complete(struct io_kiocb *req, __poll_t mask)
>>> if (req->poll.events & EPOLLONESHOT)
>>> flags = 0;
>>> if (!io_cqring_fill_event(ctx, req->user_data, error, flags)) {
>>> - io_poll_remove_waitqs(req);
> Currently I only see it does that with io_poll_remove_waitqs() when
> cqring overflow and then ocqe allocation failed. Using
> io_poll_remove_waitqs() here is not very suitable since (1) it calls
> __io_poll_remove_one() which set poll->cancelled = true, why do we set
> poll->cancelled and poll->done to true at the same time though I think
> that doesn't cause any problem. (2) it does
> list_del_init(&poll->wait.entry) and hash_del(&req->hash_node) which
> has been already done.
> Correct me if I'm wrong since I may misunderstand the code.
>
> Regards,
> Hao
>>> req->poll.done = true;
>>> flags = 0;
>>> }
>>> @@ -4926,6 +4925,7 @@ static void io_poll_task_func(struct io_kiocb *req)
>>> done = io_poll_complete(req, req->result);
>>> if (done) {
>>> + io_poll_remove_double(req);
>>> hash_del(&req->hash_node);
>>> } else {
>>> req->result = 0;
>>> @@ -5113,7 +5113,7 @@ static __poll_t __io_arm_poll_handler(struct io_kiocb *req,
>>> ipt->error = -EINVAL;
>>> spin_lock_irq(&ctx->completion_lock);
>>> - if (ipt->error)
>>> + if (ipt->error || (mask && (poll->events & EPOLLONESHOT)))
>>> io_poll_remove_double(req);
>>> if (likely(poll->head)) {
>>> spin_lock(&poll->head->lock);
>>> @@ -5185,7 +5185,6 @@ static int io_arm_poll_handler(struct io_kiocb *req)
>>> ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask,
>>> io_async_wake);
>>> if (ret || ipt.error) {
>>> - io_poll_remove_double(req);
>>> spin_unlock_irq(&ctx->completion_lock);
>>> if (ret)
>>> return IO_APOLL_READY;
>>>
>>
>
--
Pavel Begunkov
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH io_uring-5.14 v2] io_uring: remove double poll wait entry for pure poll
2021-07-26 12:40 ` Pavel Begunkov
@ 2021-07-26 14:39 ` Hao Xu
2021-07-27 22:46 ` Jens Axboe
0 siblings, 1 reply; 8+ messages in thread
From: Hao Xu @ 2021-07-26 14:39 UTC (permalink / raw)
To: Pavel Begunkov, Jens Axboe; +Cc: io-uring, Joseph Qi
在 2021/7/26 下午8:40, Pavel Begunkov 写道:
> On 7/24/21 5:48 AM, Hao Xu wrote:
>> 在 2021/7/23 下午10:31, Pavel Begunkov 写道:
>>> On 7/23/21 10:22 AM, Hao Xu wrote:
>>>> For pure poll requests, we should remove the double poll wait entry.
>>>> And io_poll_remove_double() is good enough for it compared with
>>>> io_poll_remove_waitqs().
>>>
>>> 5.14 in the subject hints me that it's a fix. Is it?
>>> Can you add what it fixes or expand on why it's better?
>> Hi Pavel, I found that for poll_add() requests, it doesn't remove the
>> double poll wait entry when it's done, neither after vfs_poll() or in
>> the poll completion handler. The patch is mainly to fix it.
>
> Ok, sounds good. Please resend with updated description, and
> let's add some tags.
>
> Fixes: 88e41cf928a6 ("io_uring: add multishot mode for IORING_OP_POLL_ADD")
> Cc: [email protected] # 5.13+
>
> Also, I'd prefer the commit title to make more clear that it's a
> fix. E.g. "io_uring: fix poll requests leaking second poll entries".
>
> Btw, seems it should fix hangs in ./poll-mshot-update
Sure，I'll send v3 soon, sorry for my unprofessionalism..
>
>
>>>
>>>> Signed-off-by: Hao Xu <[email protected]>
>>>> ---
>>>>
>>>> v1-->v2
>>>> delete redundant io_poll_remove_double()
>>>>
>>>> fs/io_uring.c | 5 ++---
>>>> 1 file changed, 2 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>>>> index f2fe4eca150b..c5fe8b9e26b4 100644
>>>> --- a/fs/io_uring.c
>>>> +++ b/fs/io_uring.c
>>>> @@ -4903,7 +4903,6 @@ static bool io_poll_complete(struct io_kiocb *req, __poll_t mask)
>>>> if (req->poll.events & EPOLLONESHOT)
>>>> flags = 0;
>>>> if (!io_cqring_fill_event(ctx, req->user_data, error, flags)) {
>>>> - io_poll_remove_waitqs(req);
>> Currently I only see it does that with io_poll_remove_waitqs() when
>> cqring overflow and then ocqe allocation failed. Using
>> io_poll_remove_waitqs() here is not very suitable since (1) it calls
>> __io_poll_remove_one() which set poll->cancelled = true, why do we set
>> poll->cancelled and poll->done to true at the same time though I think
>> that doesn't cause any problem. (2) it does
>> list_del_init(&poll->wait.entry) and hash_del(&req->hash_node) which
>> has been already done.
>> Correct me if I'm wrong since I may misunderstand the code.
>>
>> Regards,
>> Hao
>>>> req->poll.done = true;
>>>> flags = 0;
>>>> }
>>>> @@ -4926,6 +4925,7 @@ static void io_poll_task_func(struct io_kiocb *req)
>>>> done = io_poll_complete(req, req->result);
>>>> if (done) {
>>>> + io_poll_remove_double(req);
>>>> hash_del(&req->hash_node);
>>>> } else {
>>>> req->result = 0;
>>>> @@ -5113,7 +5113,7 @@ static __poll_t __io_arm_poll_handler(struct io_kiocb *req,
>>>> ipt->error = -EINVAL;
>>>> spin_lock_irq(&ctx->completion_lock);
>>>> - if (ipt->error)
>>>> + if (ipt->error || (mask && (poll->events & EPOLLONESHOT)))
>>>> io_poll_remove_double(req);
>>>> if (likely(poll->head)) {
>>>> spin_lock(&poll->head->lock);
>>>> @@ -5185,7 +5185,6 @@ static int io_arm_poll_handler(struct io_kiocb *req)
>>>> ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask,
>>>> io_async_wake);
>>>> if (ret || ipt.error) {
>>>> - io_poll_remove_double(req);
>>>> spin_unlock_irq(&ctx->completion_lock);
>>>> if (ret)
>>>> return IO_APOLL_READY;
>>>>
>>>
>>
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH io_uring-5.14 v2] io_uring: remove double poll wait entry for pure poll
2021-07-26 14:39 ` Hao Xu
@ 2021-07-27 22:46 ` Jens Axboe
2021-07-28 6:06 ` Hao Xu
0 siblings, 1 reply; 8+ messages in thread
From: Jens Axboe @ 2021-07-27 22:46 UTC (permalink / raw)
To: Hao Xu, Pavel Begunkov; +Cc: io-uring, Joseph Qi
On 7/26/21 8:39 AM, Hao Xu wrote:
> 在 2021/7/26 下午8:40, Pavel Begunkov 写道:
>> On 7/24/21 5:48 AM, Hao Xu wrote:
>>> 在 2021/7/23 下午10:31, Pavel Begunkov 写道:
>>>> On 7/23/21 10:22 AM, Hao Xu wrote:
>>>>> For pure poll requests, we should remove the double poll wait entry.
>>>>> And io_poll_remove_double() is good enough for it compared with
>>>>> io_poll_remove_waitqs().
>>>>
>>>> 5.14 in the subject hints me that it's a fix. Is it?
>>>> Can you add what it fixes or expand on why it's better?
>>> Hi Pavel, I found that for poll_add() requests, it doesn't remove the
>>> double poll wait entry when it's done, neither after vfs_poll() or in
>>> the poll completion handler. The patch is mainly to fix it.
>>
>> Ok, sounds good. Please resend with updated description, and
>> let's add some tags.
>>
>> Fixes: 88e41cf928a6 ("io_uring: add multishot mode for IORING_OP_POLL_ADD")
>> Cc: [email protected] # 5.13+
>>
>> Also, I'd prefer the commit title to make more clear that it's a
>> fix. E.g. "io_uring: fix poll requests leaking second poll entries".
>>
>> Btw, seems it should fix hangs in ./poll-mshot-update
> Sure，I'll send v3 soon, sorry for my unprofessionalism..
Are you going to send out v3?
--
Jens Axboe
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH io_uring-5.14 v2] io_uring: remove double poll wait entry for pure poll
2021-07-27 22:46 ` Jens Axboe
@ 2021-07-28 6:06 ` Hao Xu
0 siblings, 0 replies; 8+ messages in thread
From: Hao Xu @ 2021-07-28 6:06 UTC (permalink / raw)
To: Jens Axboe, Pavel Begunkov; +Cc: io-uring, Joseph Qi
在 2021/7/28 上午6:46, Jens Axboe 写道:
> On 7/26/21 8:39 AM, Hao Xu wrote:
>> 在 2021/7/26 下午8:40, Pavel Begunkov 写道:
>>> On 7/24/21 5:48 AM, Hao Xu wrote:
>>>> 在 2021/7/23 下午10:31, Pavel Begunkov 写道:
>>>>> On 7/23/21 10:22 AM, Hao Xu wrote:
>>>>>> For pure poll requests, we should remove the double poll wait entry.
>>>>>> And io_poll_remove_double() is good enough for it compared with
>>>>>> io_poll_remove_waitqs().
>>>>>
>>>>> 5.14 in the subject hints me that it's a fix. Is it?
>>>>> Can you add what it fixes or expand on why it's better?
>>>> Hi Pavel, I found that for poll_add() requests, it doesn't remove the
>>>> double poll wait entry when it's done, neither after vfs_poll() or in
>>>> the poll completion handler. The patch is mainly to fix it.
>>>
>>> Ok, sounds good. Please resend with updated description, and
>>> let's add some tags.
>>>
>>> Fixes: 88e41cf928a6 ("io_uring: add multishot mode for IORING_OP_POLL_ADD")
>>> Cc: [email protected] # 5.13+
>>>
>>> Also, I'd prefer the commit title to make more clear that it's a
>>> fix. E.g. "io_uring: fix poll requests leaking second poll entries".
>>>
>>> Btw, seems it should fix hangs in ./poll-mshot-update
>> Sure，I'll send v3 soon, sorry for my unprofessionalism..
>
> Are you going to send out v3?
>
v3 sent. Btw I'm working on letting fast poll support multishot,
I believe that will benefit non-persistent programming, let's see
if it helps accept().
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2021-07-28 6:06 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
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2021-07-23 9:22 [PATCH io_uring-5.14 v2] io_uring: remove double poll wait entry for pure poll Hao Xu
2021-07-23 14:31 ` Pavel Begunkov
2021-07-23 16:22 ` Jens Axboe
2021-07-24 4:48 ` Hao Xu
2021-07-26 12:40 ` Pavel Begunkov
2021-07-26 14:39 ` Hao Xu
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2021-07-28 6:06 ` Hao Xu
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