| Message ID | 5b9f6716006df7e817f18bd555aee2f8f9c8b0c3.1684154817.git.asml.silence@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Enable IOU_F_TWQ_LAZY_WAKE for passthrough | expand |
On Mon, May 15, 2023 at 01:54:42PM +0100, Pavel Begunkov wrote: >We want to use IOU_F_TWQ_LAZY_WAKE in commands. First, introduce a new >cmd tw helper accepting TWQ flags, and then add >io_uring_cmd_do_in_task_laz() that will pass IOU_F_TWQ_LAZY_WAKE and >imply the "lazy" semantics, i.e. it posts no more than 1 CQE and >delaying execution of this tw should not prevent forward progress. > >Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> >--- > include/linux/io_uring.h | 18 ++++++++++++++++-- > io_uring/uring_cmd.c | 16 ++++++++++++---- > 2 files changed, 28 insertions(+), 6 deletions(-) > >diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h >index 7fe31b2cd02f..bb9c666bd584 100644 >--- a/include/linux/io_uring.h >+++ b/include/linux/io_uring.h >@@ -46,13 +46,23 @@ int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw, > struct iov_iter *iter, void *ioucmd); > void io_uring_cmd_done(struct io_uring_cmd *cmd, ssize_t ret, ssize_t res2, > unsigned issue_flags); >-void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >- void (*task_work_cb)(struct io_uring_cmd *, unsigned)); > struct sock *io_uring_get_socket(struct file *file); > void __io_uring_cancel(bool cancel_all); > void __io_uring_free(struct task_struct *tsk); > void io_uring_unreg_ringfd(void); > const char *io_uring_get_opcode(u8 opcode); >+void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd, >+ void (*task_work_cb)(struct io_uring_cmd *, unsigned), >+ unsigned flags); >+/* users should follow semantics of IOU_F_TWQ_LAZY_WAKE */ Should this also translate to some warn_on anywhere? >+void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, >+ void (*task_work_cb)(struct io_uring_cmd *, unsigned)); >+ >+static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >+ void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >+{ >+ __io_uring_cmd_do_in_task(ioucmd, task_work_cb, 0); >+} > > static inline void io_uring_files_cancel(void) > { >@@ -85,6 +95,10 @@ static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, > void (*task_work_cb)(struct io_uring_cmd *, unsigned)) > { > } >+static inline void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, >+ void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >+{ >+} > static inline struct sock *io_uring_get_socket(struct file *file) > { > return NULL; >diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c >index 5e32db48696d..476c7877ce58 100644 >--- a/io_uring/uring_cmd.c >+++ b/io_uring/uring_cmd.c >@@ -20,16 +20,24 @@ static void io_uring_cmd_work(struct io_kiocb *req, struct io_tw_state *ts) > ioucmd->task_work_cb(ioucmd, issue_flags); > } > >-void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >- void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >+void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd, >+ void (*task_work_cb)(struct io_uring_cmd *, unsigned), >+ unsigned flags) > { > struct io_kiocb *req = cmd_to_io_kiocb(ioucmd); > > ioucmd->task_work_cb = task_work_cb; > req->io_task_work.func = io_uring_cmd_work; >- io_req_task_work_add(req); >+ __io_req_task_work_add(req, flags); >+} >+EXPORT_SYMBOL_GPL(__io_uring_cmd_do_in_task); Any reason to export this? No one is using this at the moment. >+void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, >+ void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >+{ >+ __io_uring_cmd_do_in_task(ioucmd, task_work_cb, IOU_F_TWQ_LAZY_WAKE); > } >-EXPORT_SYMBOL_GPL(io_uring_cmd_complete_in_task); >+EXPORT_SYMBOL_GPL(io_uring_cmd_do_in_task_lazy); Seems you did not want callers to pass the the new flag (LAZY_WAKE) and therefore this helper. And if you did not want callers to know about this flag (internal details of io_uring), it would be better to have two exported helpers io_uring_cmd_do_in_task_lazy() and io_uring_cmd_complete_in_task(). Both will use the internal helper __io_uring_cmd_do_in_task with different flag.
On 5/16/23 11:00, Kanchan Joshi wrote: > On Mon, May 15, 2023 at 01:54:42PM +0100, Pavel Begunkov wrote: >> We want to use IOU_F_TWQ_LAZY_WAKE in commands. First, introduce a new >> cmd tw helper accepting TWQ flags, and then add >> io_uring_cmd_do_in_task_laz() that will pass IOU_F_TWQ_LAZY_WAKE and >> imply the "lazy" semantics, i.e. it posts no more than 1 CQE and >> delaying execution of this tw should not prevent forward progress. >> >> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> >> --- >> include/linux/io_uring.h | 18 ++++++++++++++++-- >> io_uring/uring_cmd.c | 16 ++++++++++++---- >> 2 files changed, 28 insertions(+), 6 deletions(-) >> >> diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h >> index 7fe31b2cd02f..bb9c666bd584 100644 >> --- a/include/linux/io_uring.h >> +++ b/include/linux/io_uring.h >> @@ -46,13 +46,23 @@ int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw, >> struct iov_iter *iter, void *ioucmd); >> void io_uring_cmd_done(struct io_uring_cmd *cmd, ssize_t ret, ssize_t res2, >> unsigned issue_flags); >> -void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >> - void (*task_work_cb)(struct io_uring_cmd *, unsigned)); >> struct sock *io_uring_get_socket(struct file *file); >> void __io_uring_cancel(bool cancel_all); >> void __io_uring_free(struct task_struct *tsk); >> void io_uring_unreg_ringfd(void); >> const char *io_uring_get_opcode(u8 opcode); >> +void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd, >> + void (*task_work_cb)(struct io_uring_cmd *, unsigned), >> + unsigned flags); >> +/* users should follow semantics of IOU_F_TWQ_LAZY_WAKE */ > > Should this also translate to some warn_on anywhere? Would love to but don't see how. We can only check it doesn't produce more than 1 CQE, but that would need nr_cqes_before = cqes_ready(); tw_item->run(); WARN_ON(cqes_ready() >= nr_cqes_before + 1); but that's just too ugly >> +void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, >> + void (*task_work_cb)(struct io_uring_cmd *, unsigned)); >> + >> +static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >> + void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >> +{ >> + __io_uring_cmd_do_in_task(ioucmd, task_work_cb, 0); >> +} >> >> static inline void io_uring_files_cancel(void) >> { >> @@ -85,6 +95,10 @@ static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >> void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >> { >> } >> +static inline void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, >> + void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >> +{ >> +} >> static inline struct sock *io_uring_get_socket(struct file *file) >> { >> return NULL; >> diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c >> index 5e32db48696d..476c7877ce58 100644 >> --- a/io_uring/uring_cmd.c >> +++ b/io_uring/uring_cmd.c >> @@ -20,16 +20,24 @@ static void io_uring_cmd_work(struct io_kiocb *req, struct io_tw_state *ts) >> ioucmd->task_work_cb(ioucmd, issue_flags); >> } >> >> -void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >> - void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >> +void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd, >> + void (*task_work_cb)(struct io_uring_cmd *, unsigned), >> + unsigned flags) >> { >> struct io_kiocb *req = cmd_to_io_kiocb(ioucmd); >> >> ioucmd->task_work_cb = task_work_cb; >> req->io_task_work.func = io_uring_cmd_work; >> - io_req_task_work_add(req); >> + __io_req_task_work_add(req, flags); >> +} >> +EXPORT_SYMBOL_GPL(__io_uring_cmd_do_in_task); --- a/include/linux/io_uring.h +++ b/include/linux/io_uring.h +static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, + void (*task_work_cb)(struct io_uring_cmd *, unsigned)) +{ + __io_uring_cmd_do_in_task(ioucmd, task_work_cb, 0); +} That should fail for nvme unless exported. > Any reason to export this? No one is using this at the moment. >> +void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, >> + void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >> +{ >> + __io_uring_cmd_do_in_task(ioucmd, task_work_cb, IOU_F_TWQ_LAZY_WAKE); >> } >> -EXPORT_SYMBOL_GPL(io_uring_cmd_complete_in_task); >> +EXPORT_SYMBOL_GPL(io_uring_cmd_do_in_task_lazy); > > Seems you did not want callers to pass the the new flag (LAZY_WAKE) and > therefore this helper. Yep, I wouldn't mind exposing just *LAZY_WAKE but don't want to let it use whatever flags there might be in the future. Initially I wanted to just make io_uring_cmd_complete_in_task and io_uring_cmd_do_in_task_lazy static inline, but that would need some code shuffling to make it clean. > And if you did not want callers to know about this flag (internal > details of io_uring), it would be better to have two exported helpers > io_uring_cmd_do_in_task_lazy() and io_uring_cmd_complete_in_task(). > Both will use the internal helper __io_uring_cmd_do_in_task with > different flag. That's how it should be in this patch
On Tue, May 16, 2023 at 07:52:23PM +0100, Pavel Begunkov wrote: >On 5/16/23 11:00, Kanchan Joshi wrote: >>On Mon, May 15, 2023 at 01:54:42PM +0100, Pavel Begunkov wrote: >>>We want to use IOU_F_TWQ_LAZY_WAKE in commands. First, introduce a new >>>cmd tw helper accepting TWQ flags, and then add >>>io_uring_cmd_do_in_task_laz() that will pass IOU_F_TWQ_LAZY_WAKE and >>>imply the "lazy" semantics, i.e. it posts no more than 1 CQE and >>>delaying execution of this tw should not prevent forward progress. >>> >>>Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> >>>--- >>>include/linux/io_uring.h | 18 ++++++++++++++++-- >>>io_uring/uring_cmd.c | 16 ++++++++++++---- >>>2 files changed, 28 insertions(+), 6 deletions(-) >>> >>>diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h >>>index 7fe31b2cd02f..bb9c666bd584 100644 >>>--- a/include/linux/io_uring.h >>>+++ b/include/linux/io_uring.h >>>@@ -46,13 +46,23 @@ int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw, >>> struct iov_iter *iter, void *ioucmd); >>>void io_uring_cmd_done(struct io_uring_cmd *cmd, ssize_t ret, ssize_t res2, >>> unsigned issue_flags); >>>-void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >>>- void (*task_work_cb)(struct io_uring_cmd *, unsigned)); >>>struct sock *io_uring_get_socket(struct file *file); >>>void __io_uring_cancel(bool cancel_all); >>>void __io_uring_free(struct task_struct *tsk); >>>void io_uring_unreg_ringfd(void); >>>const char *io_uring_get_opcode(u8 opcode); >>>+void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd, >>>+ void (*task_work_cb)(struct io_uring_cmd *, unsigned), >>>+ unsigned flags); >>>+/* users should follow semantics of IOU_F_TWQ_LAZY_WAKE */ >> >>Should this also translate to some warn_on anywhere? > >Would love to but don't see how. We can only check it doesn't >produce more than 1 CQE, but that would need > >nr_cqes_before = cqes_ready(); >tw_item->run(); >WARN_ON(cqes_ready() >= nr_cqes_before + 1); > >but that's just too ugly > > >>>+void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, >>>+ void (*task_work_cb)(struct io_uring_cmd *, unsigned)); >>>+ >>>+static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >>>+ void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >>>+{ >>>+ __io_uring_cmd_do_in_task(ioucmd, task_work_cb, 0); >>>+} >>> >>>static inline void io_uring_files_cancel(void) >>>{ >>>@@ -85,6 +95,10 @@ static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >>> void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >>>{ >>>} >>>+static inline void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, >>>+ void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >>>+{ >>>+} >>>static inline struct sock *io_uring_get_socket(struct file *file) >>>{ >>> return NULL; >>>diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c >>>index 5e32db48696d..476c7877ce58 100644 >>>--- a/io_uring/uring_cmd.c >>>+++ b/io_uring/uring_cmd.c >>>@@ -20,16 +20,24 @@ static void io_uring_cmd_work(struct io_kiocb *req, struct io_tw_state *ts) >>> ioucmd->task_work_cb(ioucmd, issue_flags); >>>} >>> >>>-void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >>>- void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >>>+void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd, >>>+ void (*task_work_cb)(struct io_uring_cmd *, unsigned), >>>+ unsigned flags) >>>{ >>> struct io_kiocb *req = cmd_to_io_kiocb(ioucmd); >>> >>> ioucmd->task_work_cb = task_work_cb; >>> req->io_task_work.func = io_uring_cmd_work; >>>- io_req_task_work_add(req); >>>+ __io_req_task_work_add(req, flags); >>>+} >>>+EXPORT_SYMBOL_GPL(__io_uring_cmd_do_in_task); > >--- a/include/linux/io_uring.h >+++ b/include/linux/io_uring.h > >+static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >+ void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >+{ >+ __io_uring_cmd_do_in_task(ioucmd, task_work_cb, 0); >+} > >That should fail for nvme unless exported. But it does not. Give it a try. >>Any reason to export this? No one is using this at the moment. >>>+void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, >>>+ void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >>>+{ >>>+ __io_uring_cmd_do_in_task(ioucmd, task_work_cb, IOU_F_TWQ_LAZY_WAKE); >>>} >>>-EXPORT_SYMBOL_GPL(io_uring_cmd_complete_in_task); >>>+EXPORT_SYMBOL_GPL(io_uring_cmd_do_in_task_lazy); >> >>Seems you did not want callers to pass the the new flag (LAZY_WAKE) and >>therefore this helper. > >Yep, I wouldn't mind exposing just *LAZY_WAKE but don't want >to let it use whatever flags there might be in the future. > >Initially I wanted to just make io_uring_cmd_complete_in_task and >io_uring_cmd_do_in_task_lazy static inline, but that would need >some code shuffling to make it clean. > >>And if you did not want callers to know about this flag (internal >>details of io_uring), it would be better to have two exported helpers >>io_uring_cmd_do_in_task_lazy() and io_uring_cmd_complete_in_task(). >>Both will use the internal helper __io_uring_cmd_do_in_task with >>different flag. > >That's how it should be in this patch Nah, in this patch __io_uring_cmd_do_in_task is exported helper. And io_uring_cmd_complete_in_task has been changed too (explicit export to header based one). Seems like bit more shuffling than what is necessary.
On 5/17/23 11:33, Kanchan Joshi wrote: > On Tue, May 16, 2023 at 07:52:23PM +0100, Pavel Begunkov wrote: >> On 5/16/23 11:00, Kanchan Joshi wrote: >>> On Mon, May 15, 2023 at 01:54:42PM +0100, Pavel Begunkov wrote: >>>> We want to use IOU_F_TWQ_LAZY_WAKE in commands. First, introduce a new >>>> cmd tw helper accepting TWQ flags, and then add >>>> io_uring_cmd_do_in_task_laz() that will pass IOU_F_TWQ_LAZY_WAKE and >>>> imply the "lazy" semantics, i.e. it posts no more than 1 CQE and >>>> delaying execution of this tw should not prevent forward progress. >>>> >>>> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> >>>> --- >>>> include/linux/io_uring.h | 18 ++++++++++++++++-- >>>> io_uring/uring_cmd.c | 16 ++++++++++++---- >>>> 2 files changed, 28 insertions(+), 6 deletions(-) >>>> >>>> diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h >>>> index 7fe31b2cd02f..bb9c666bd584 100644 >>>> --- a/include/linux/io_uring.h >>>> +++ b/include/linux/io_uring.h >>>> @@ -46,13 +46,23 @@ int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw, >>>> struct iov_iter *iter, void *ioucmd); >>>> void io_uring_cmd_done(struct io_uring_cmd *cmd, ssize_t ret, ssize_t res2, >>>> unsigned issue_flags); >>>> -void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >>>> - void (*task_work_cb)(struct io_uring_cmd *, unsigned)); >>>> struct sock *io_uring_get_socket(struct file *file); >>>> void __io_uring_cancel(bool cancel_all); >>>> void __io_uring_free(struct task_struct *tsk); >>>> void io_uring_unreg_ringfd(void); >>>> const char *io_uring_get_opcode(u8 opcode); >>>> +void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd, >>>> + void (*task_work_cb)(struct io_uring_cmd *, unsigned), >>>> + unsigned flags); >>>> +/* users should follow semantics of IOU_F_TWQ_LAZY_WAKE */ >>> >>> Should this also translate to some warn_on anywhere? >> >> Would love to but don't see how. We can only check it doesn't >> produce more than 1 CQE, but that would need >> >> nr_cqes_before = cqes_ready(); >> tw_item->run(); >> WARN_ON(cqes_ready() >= nr_cqes_before + 1); >> >> but that's just too ugly >> >> >>>> +void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, >>>> + void (*task_work_cb)(struct io_uring_cmd *, unsigned)); >>>> + >>>> +static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >>>> + void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >>>> +{ >>>> + __io_uring_cmd_do_in_task(ioucmd, task_work_cb, 0); >>>> +} >>>> >>>> static inline void io_uring_files_cancel(void) >>>> { >>>> @@ -85,6 +95,10 @@ static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >>>> void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >>>> { >>>> } >>>> +static inline void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, >>>> + void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >>>> +{ >>>> +} >>>> static inline struct sock *io_uring_get_socket(struct file *file) >>>> { >>>> return NULL; >>>> diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c >>>> index 5e32db48696d..476c7877ce58 100644 >>>> --- a/io_uring/uring_cmd.c >>>> +++ b/io_uring/uring_cmd.c >>>> @@ -20,16 +20,24 @@ static void io_uring_cmd_work(struct io_kiocb *req, struct io_tw_state *ts) >>>> ioucmd->task_work_cb(ioucmd, issue_flags); >>>> } >>>> >>>> -void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >>>> - void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >>>> +void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd, >>>> + void (*task_work_cb)(struct io_uring_cmd *, unsigned), >>>> + unsigned flags) >>>> { >>>> struct io_kiocb *req = cmd_to_io_kiocb(ioucmd); >>>> >>>> ioucmd->task_work_cb = task_work_cb; >>>> req->io_task_work.func = io_uring_cmd_work; >>>> - io_req_task_work_add(req); >>>> + __io_req_task_work_add(req, flags); >>>> +} >>>> +EXPORT_SYMBOL_GPL(__io_uring_cmd_do_in_task); >> >> --- a/include/linux/io_uring.h >> +++ b/include/linux/io_uring.h >> >> +static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >> + void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >> +{ >> + __io_uring_cmd_do_in_task(ioucmd, task_work_cb, 0); >> +} >> >> That should fail for nvme unless exported. > > But it does not. Give it a try. > >>> Any reason to export this? No one is using this at the moment. >>>> +void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, >>>> + void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >>>> +{ >>>> + __io_uring_cmd_do_in_task(ioucmd, task_work_cb, IOU_F_TWQ_LAZY_WAKE); >>>> } >>>> -EXPORT_SYMBOL_GPL(io_uring_cmd_complete_in_task); >>>> +EXPORT_SYMBOL_GPL(io_uring_cmd_do_in_task_lazy); >>> >>> Seems you did not want callers to pass the the new flag (LAZY_WAKE) and >>> therefore this helper. >> >> Yep, I wouldn't mind exposing just *LAZY_WAKE but don't want >> to let it use whatever flags there might be in the future. >> >> Initially I wanted to just make io_uring_cmd_complete_in_task and >> io_uring_cmd_do_in_task_lazy static inline, but that would need >> some code shuffling to make it clean. >> >>> And if you did not want callers to know about this flag (internal >>> details of io_uring), it would be better to have two exported helpers >>> io_uring_cmd_do_in_task_lazy() and io_uring_cmd_complete_in_task(). >>> Both will use the internal helper __io_uring_cmd_do_in_task with >>> different flag. >> >> That's how it should be in this patch > > Nah, in this patch __io_uring_cmd_do_in_task is exported helper. And > io_uring_cmd_complete_in_task has been changed too (explicit export to > header based one). Seems like bit more shuffling than what is necessary Ok, I'll check, thanks
On 5/17/23 11:33, Kanchan Joshi wrote: > On Tue, May 16, 2023 at 07:52:23PM +0100, Pavel Begunkov wrote: >> On 5/16/23 11:00, Kanchan Joshi wrote: >>> On Mon, May 15, 2023 at 01:54:42PM +0100, Pavel Begunkov wrote: >>>> We want to use IOU_F_TWQ_LAZY_WAKE in commands. First, introduce a new >>>> cmd tw helper accepting TWQ flags, and then add >>>> io_uring_cmd_do_in_task_laz() that will pass IOU_F_TWQ_LAZY_WAKE and >>>> imply the "lazy" semantics, i.e. it posts no more than 1 CQE and >>>> delaying execution of this tw should not prevent forward progress. >>>> >>>> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> >>>> --- [...] >>>> diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c >>>> index 5e32db48696d..476c7877ce58 100644 >>>> --- a/io_uring/uring_cmd.c >>>> +++ b/io_uring/uring_cmd.c >>>> @@ -20,16 +20,24 @@ static void io_uring_cmd_work(struct io_kiocb *req, struct io_tw_state *ts) >>>> ioucmd->task_work_cb(ioucmd, issue_flags); >>>> } >>>> >>>> -void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >>>> - void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >>>> +void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd, >>>> + void (*task_work_cb)(struct io_uring_cmd *, unsigned), >>>> + unsigned flags) >>>> { >>>> struct io_kiocb *req = cmd_to_io_kiocb(ioucmd); >>>> >>>> ioucmd->task_work_cb = task_work_cb; >>>> req->io_task_work.func = io_uring_cmd_work; >>>> - io_req_task_work_add(req); >>>> + __io_req_task_work_add(req, flags); >>>> +} >>>> +EXPORT_SYMBOL_GPL(__io_uring_cmd_do_in_task); >> >> --- a/include/linux/io_uring.h >> +++ b/include/linux/io_uring.h >> >> +static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, >> + void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >> +{ >> + __io_uring_cmd_do_in_task(ioucmd, task_work_cb, 0); >> +} >> >> That should fail for nvme unless exported. > > But it does not. Give it a try. Took the first patch, killed the export and compiled ublk and nvme as modules: ERROR: modpost: "__io_uring_cmd_do_in_task" [drivers/block/ublk_drv.ko] undefined! ERROR: modpost: "__io_uring_cmd_do_in_task" [drivers/nvme/host/nvme-core.ko] undefined! diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c index 476c7877ce58..3bb43122a683 100644 --- a/io_uring/uring_cmd.c +++ b/io_uring/uring_cmd.c @@ -30,7 +30,6 @@ void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd, req->io_task_work.func = io_uring_cmd_work; __io_req_task_work_add(req, flags); } -EXPORT_SYMBOL_GPL(__io_uring_cmd_do_in_task); >>> Any reason to export this? No one is using this at the moment. >>>> +void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, >>>> + void (*task_work_cb)(struct io_uring_cmd *, unsigned)) >>>> +{ >>>> + __io_uring_cmd_do_in_task(ioucmd, task_work_cb, IOU_F_TWQ_LAZY_WAKE); >>>> } >>>> -EXPORT_SYMBOL_GPL(io_uring_cmd_complete_in_task); >>>> +EXPORT_SYMBOL_GPL(io_uring_cmd_do_in_task_lazy); >>> >>> Seems you did not want callers to pass the the new flag (LAZY_WAKE) and >>> therefore this helper. >> >> Yep, I wouldn't mind exposing just *LAZY_WAKE but don't want >> to let it use whatever flags there might be in the future. >> >> Initially I wanted to just make io_uring_cmd_complete_in_task and >> io_uring_cmd_do_in_task_lazy static inline, but that would need >> some code shuffling to make it clean. >> >>> And if you did not want callers to know about this flag (internal >>> details of io_uring), it would be better to have two exported helpers >>> io_uring_cmd_do_in_task_lazy() and io_uring_cmd_complete_in_task(). >>> Both will use the internal helper __io_uring_cmd_do_in_task with >>> different flag. >> >> That's how it should be in this patch > > Nah, in this patch __io_uring_cmd_do_in_task is exported helper. And > io_uring_cmd_complete_in_task has been changed too (explicit export to > header based one). Seems like bit more shuffling than what is necessary. With the end goal to turn them into inline helpers later on I think it's fine.
diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h index 7fe31b2cd02f..bb9c666bd584 100644 --- a/include/linux/io_uring.h +++ b/include/linux/io_uring.h @@ -46,13 +46,23 @@ int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw, struct iov_iter *iter, void *ioucmd); void io_uring_cmd_done(struct io_uring_cmd *cmd, ssize_t ret, ssize_t res2, unsigned issue_flags); -void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, - void (*task_work_cb)(struct io_uring_cmd *, unsigned)); struct sock *io_uring_get_socket(struct file *file); void __io_uring_cancel(bool cancel_all); void __io_uring_free(struct task_struct *tsk); void io_uring_unreg_ringfd(void); const char *io_uring_get_opcode(u8 opcode); +void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd, + void (*task_work_cb)(struct io_uring_cmd *, unsigned), + unsigned flags); +/* users should follow semantics of IOU_F_TWQ_LAZY_WAKE */ +void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, + void (*task_work_cb)(struct io_uring_cmd *, unsigned)); + +static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, + void (*task_work_cb)(struct io_uring_cmd *, unsigned)) +{ + __io_uring_cmd_do_in_task(ioucmd, task_work_cb, 0); +} static inline void io_uring_files_cancel(void) { @@ -85,6 +95,10 @@ static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, void (*task_work_cb)(struct io_uring_cmd *, unsigned)) { } +static inline void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, + void (*task_work_cb)(struct io_uring_cmd *, unsigned)) +{ +} static inline struct sock *io_uring_get_socket(struct file *file) { return NULL; diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c index 5e32db48696d..476c7877ce58 100644 --- a/io_uring/uring_cmd.c +++ b/io_uring/uring_cmd.c @@ -20,16 +20,24 @@ static void io_uring_cmd_work(struct io_kiocb *req, struct io_tw_state *ts) ioucmd->task_work_cb(ioucmd, issue_flags); } -void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, - void (*task_work_cb)(struct io_uring_cmd *, unsigned)) +void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd, + void (*task_work_cb)(struct io_uring_cmd *, unsigned), + unsigned flags) { struct io_kiocb *req = cmd_to_io_kiocb(ioucmd); ioucmd->task_work_cb = task_work_cb; req->io_task_work.func = io_uring_cmd_work; - io_req_task_work_add(req); + __io_req_task_work_add(req, flags); +} +EXPORT_SYMBOL_GPL(__io_uring_cmd_do_in_task); + +void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd, + void (*task_work_cb)(struct io_uring_cmd *, unsigned)) +{ + __io_uring_cmd_do_in_task(ioucmd, task_work_cb, IOU_F_TWQ_LAZY_WAKE); } -EXPORT_SYMBOL_GPL(io_uring_cmd_complete_in_task); +EXPORT_SYMBOL_GPL(io_uring_cmd_do_in_task_lazy); static inline void io_req_set_cqe32_extra(struct io_kiocb *req, u64 extra1, u64 extra2)
We want to use IOU_F_TWQ_LAZY_WAKE in commands. First, introduce a new cmd tw helper accepting TWQ flags, and then add io_uring_cmd_do_in_task_laz() that will pass IOU_F_TWQ_LAZY_WAKE and imply the "lazy" semantics, i.e. it posts no more than 1 CQE and delaying execution of this tw should not prevent forward progress. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> --- include/linux/io_uring.h | 18 ++++++++++++++++-- io_uring/uring_cmd.c | 16 ++++++++++++---- 2 files changed, 28 insertions(+), 6 deletions(-)