* [PATCH] io-wq: simplify code in __io_worker_busy
@ 2021-04-02 10:18 Hao Xu
2021-04-02 10:38 ` Pavel Begunkov
0 siblings, 1 reply; 10+ messages in thread
From: Hao Xu @ 2021-04-02 10:18 UTC (permalink / raw)
To: Jens Axboe; +Cc: io-uring, Pavel Begunkov, Joseph Qi
leverage xor to simplify code in __io_worker_busy
Signed-off-by: Hao Xu <[email protected]>
---
fs/io-wq.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 7434eb40ca8c..f77e4704d7c7 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -292,16 +292,11 @@ static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
worker_bound = (worker->flags & IO_WORKER_F_BOUND) != 0;
work_bound = (work->flags & IO_WQ_WORK_UNBOUND) == 0;
if (worker_bound != work_bound) {
+ int index = work_bound ? IO_WQ_ACCT_UNBOUND : IO_WQ_ACCT_BOUND;
io_wqe_dec_running(worker);
- if (work_bound) {
- worker->flags |= IO_WORKER_F_BOUND;
- wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers--;
- wqe->acct[IO_WQ_ACCT_BOUND].nr_workers++;
- } else {
- worker->flags &= ~IO_WORKER_F_BOUND;
- wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers++;
- wqe->acct[IO_WQ_ACCT_BOUND].nr_workers--;
- }
+ worker->flags ^= IO_WORKER_F_BOUND;
+ wqe->acct[index].nr_workers--;
+ wqe->acct[index^1].nr_workers++;
io_wqe_inc_running(worker);
}
}
--
1.8.3.1
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH] io-wq: simplify code in __io_worker_busy
2021-04-02 10:18 [PATCH] io-wq: simplify code in __io_worker_busy Hao Xu
@ 2021-04-02 10:38 ` Pavel Begunkov
2021-04-04 19:17 ` Jens Axboe
2021-04-05 7:36 ` [PATCH v2] " Hao Xu
0 siblings, 2 replies; 10+ messages in thread
From: Pavel Begunkov @ 2021-04-02 10:38 UTC (permalink / raw)
To: Hao Xu, Jens Axboe; +Cc: io-uring, Joseph Qi
On 02/04/2021 11:18, Hao Xu wrote:
> leverage xor to simplify code in __io_worker_busy
I don't like hard-coded ^1 because if indexes change it may break.
One option is to leave it to the compiler:
idx = bound : WQ_BOUND ? WQ_UNBOUND;
compl_idx = bound : WQ_UNBOUND ? WQ_BOUND;
Or add a BUILD_BUG_ON() checking that WQ_BOUND and WQ_UNBOUND
are mod 2 complementary.
>
> Signed-off-by: Hao Xu <[email protected]>
> ---
> fs/io-wq.c | 13 ++++---------
> 1 file changed, 4 insertions(+), 9 deletions(-)
>
> diff --git a/fs/io-wq.c b/fs/io-wq.c
> index 7434eb40ca8c..f77e4704d7c7 100644
> --- a/fs/io-wq.c
> +++ b/fs/io-wq.c
> @@ -292,16 +292,11 @@ static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
> worker_bound = (worker->flags & IO_WORKER_F_BOUND) != 0;
> work_bound = (work->flags & IO_WQ_WORK_UNBOUND) == 0;
> if (worker_bound != work_bound) {
> + int index = work_bound ? IO_WQ_ACCT_UNBOUND : IO_WQ_ACCT_BOUND;
> io_wqe_dec_running(worker);
> - if (work_bound) {
> - worker->flags |= IO_WORKER_F_BOUND;
> - wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers--;
> - wqe->acct[IO_WQ_ACCT_BOUND].nr_workers++;
> - } else {
> - worker->flags &= ~IO_WORKER_F_BOUND;
> - wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers++;
> - wqe->acct[IO_WQ_ACCT_BOUND].nr_workers--;
> - }
> + worker->flags ^= IO_WORKER_F_BOUND;
> + wqe->acct[index].nr_workers--;
> + wqe->acct[index^1].nr_workers++;
> io_wqe_inc_running(worker);
> }
> }
>
--
Pavel Begunkov
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH] io-wq: simplify code in __io_worker_busy
2021-04-02 10:38 ` Pavel Begunkov
@ 2021-04-04 19:17 ` Jens Axboe
2021-04-05 7:53 ` [PATCH v3] " Hao Xu
2021-04-05 7:36 ` [PATCH v2] " Hao Xu
1 sibling, 1 reply; 10+ messages in thread
From: Jens Axboe @ 2021-04-04 19:17 UTC (permalink / raw)
To: Pavel Begunkov, Hao Xu; +Cc: io-uring, Joseph Qi
On 4/2/21 4:38 AM, Pavel Begunkov wrote:
> On 02/04/2021 11:18, Hao Xu wrote:
>> leverage xor to simplify code in __io_worker_busy
>
> I don't like hard-coded ^1 because if indexes change it may break.
> One option is to leave it to the compiler:
>
> idx = bound : WQ_BOUND ? WQ_UNBOUND;
> compl_idx = bound : WQ_UNBOUND ? WQ_BOUND;
>
> Or add a BUILD_BUG_ON() checking that WQ_BOUND and WQ_UNBOUND
> are mod 2 complementary.
Was going to suggest just that, just add a BUILD_BUG_ON() to catch
any changes there. The code is way cleaner with the XOR trick.
Hao, can you resend with that?
--
Jens Axboe
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v3] io-wq: simplify code in __io_worker_busy
2021-04-04 19:17 ` Jens Axboe
@ 2021-04-05 7:53 ` Hao Xu
2021-04-05 21:46 ` Jens Axboe
0 siblings, 1 reply; 10+ messages in thread
From: Hao Xu @ 2021-04-05 7:53 UTC (permalink / raw)
To: Jens Axboe; +Cc: io-uring, Pavel Begunkov, Joseph Qi
leverage xor to simplify code in __io_worker_busy
Signed-off-by: Hao Xu <[email protected]>
---
fs/io-wq.c | 17 +++++++----------
1 file changed, 7 insertions(+), 10 deletions(-)
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 433c4d3c3c1c..8d8324eba2ec 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -276,10 +276,12 @@ static void io_wqe_dec_running(struct io_worker *worker)
*/
static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
struct io_wq_work *work)
- __must_hold(wqe->lock)
+ __must_hold(w qe->lock)
{
bool worker_bound, work_bound;
+ BUILD_BUG_ON((IO_WQ_ACCT_UNBOUND ^ IO_WQ_ACCT_BOUND) != 1);
+
if (worker->flags & IO_WORKER_F_FREE) {
worker->flags &= ~IO_WORKER_F_FREE;
hlist_nulls_del_init_rcu(&worker->nulls_node);
@@ -292,16 +294,11 @@ static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
worker_bound = (worker->flags & IO_WORKER_F_BOUND) != 0;
work_bound = (work->flags & IO_WQ_WORK_UNBOUND) == 0;
if (worker_bound != work_bound) {
+ int index = work_bound ? IO_WQ_ACCT_UNBOUND : IO_WQ_ACCT_BOUND;
io_wqe_dec_running(worker);
- if (work_bound) {
- worker->flags |= IO_WORKER_F_BOUND;
- wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers--;
- wqe->acct[IO_WQ_ACCT_BOUND].nr_workers++;
- } else {
- worker->flags &= ~IO_WORKER_F_BOUND;
- wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers++;
- wqe->acct[IO_WQ_ACCT_BOUND].nr_workers--;
- }
+ worker->flags ^= IO_WORKER_F_BOUND;
+ wqe->acct[index].nr_workers--;
+ wqe->acct[index ^ 1].nr_workers++;
io_wqe_inc_running(worker);
}
}
--
1.8.3.1
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH v3] io-wq: simplify code in __io_worker_busy
2021-04-05 7:53 ` [PATCH v3] " Hao Xu
@ 2021-04-05 21:46 ` Jens Axboe
2021-04-06 2:18 ` Hao Xu
2021-04-06 3:08 ` [PATCH v4] " Hao Xu
0 siblings, 2 replies; 10+ messages in thread
From: Jens Axboe @ 2021-04-05 21:46 UTC (permalink / raw)
To: Hao Xu; +Cc: io-uring, Pavel Begunkov, Joseph Qi
On 4/5/21 1:53 AM, Hao Xu wrote:
> leverage xor to simplify code in __io_worker_busy
>
> Signed-off-by: Hao Xu <[email protected]>
> ---
> fs/io-wq.c | 17 +++++++----------
> 1 file changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/fs/io-wq.c b/fs/io-wq.c
> index 433c4d3c3c1c..8d8324eba2ec 100644
> --- a/fs/io-wq.c
> +++ b/fs/io-wq.c
> @@ -276,10 +276,12 @@ static void io_wqe_dec_running(struct io_worker *worker)
> */
> static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
> struct io_wq_work *work)
> - __must_hold(wqe->lock)
> + __must_hold(w qe->lock)
Looks like something is off there? I see a v2 as well, but this one is
later, so...
--
Jens Axboe
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v3] io-wq: simplify code in __io_worker_busy
2021-04-05 21:46 ` Jens Axboe
@ 2021-04-06 2:18 ` Hao Xu
2021-04-06 3:08 ` [PATCH v4] " Hao Xu
1 sibling, 0 replies; 10+ messages in thread
From: Hao Xu @ 2021-04-06 2:18 UTC (permalink / raw)
To: Jens Axboe; +Cc: io-uring, Pavel Begunkov, Joseph Qi
在 2021/4/6 上午5:46, Jens Axboe 写道:
> On 4/5/21 1:53 AM, Hao Xu wrote:
>> leverage xor to simplify code in __io_worker_busy
>>
>> Signed-off-by: Hao Xu <[email protected]>
>> ---
>> fs/io-wq.c | 17 +++++++----------
>> 1 file changed, 7 insertions(+), 10 deletions(-)
>>
>> diff --git a/fs/io-wq.c b/fs/io-wq.c
>> index 433c4d3c3c1c..8d8324eba2ec 100644
>> --- a/fs/io-wq.c
>> +++ b/fs/io-wq.c
>> @@ -276,10 +276,12 @@ static void io_wqe_dec_running(struct io_worker *worker)
>> */
>> static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
>> struct io_wq_work *work)
>> - __must_hold(wqe->lock)
>> + __must_hold(w qe->lock)
>
> Looks like something is off there? I see a v2 as well, but this one is
> later, so...
>
v2 is sent before I saw your comment, actully both v2 and v3 make sense
for me, but now I prefer v3.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v4] io-wq: simplify code in __io_worker_busy
2021-04-05 21:46 ` Jens Axboe
2021-04-06 2:18 ` Hao Xu
@ 2021-04-06 3:08 ` Hao Xu
2021-04-06 15:36 ` Jens Axboe
2021-04-07 18:28 ` Pavel Begunkov
1 sibling, 2 replies; 10+ messages in thread
From: Hao Xu @ 2021-04-06 3:08 UTC (permalink / raw)
To: Jens Axboe; +Cc: io-uring, Pavel Begunkov, Joseph Qi
leverage xor to simplify code in __io_worker_busy
Signed-off-by: Hao Xu <[email protected]>
---
Sorry, typo by mistake...
fs/io-wq.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 2dd2d4b1e538..fa2383cb4d50 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -329,6 +329,8 @@ static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
{
bool worker_bound, work_bound;
+ BUILD_BUG_ON((IO_WQ_ACCT_UNBOUND ^ IO_WQ_ACCT_BOUND) != 1);
+
if (worker->flags & IO_WORKER_F_FREE) {
worker->flags &= ~IO_WORKER_F_FREE;
hlist_nulls_del_init_rcu(&worker->nulls_node);
@@ -341,16 +343,11 @@ static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
worker_bound = (worker->flags & IO_WORKER_F_BOUND) != 0;
work_bound = (work->flags & IO_WQ_WORK_UNBOUND) == 0;
if (worker_bound != work_bound) {
+ int index = work_bound ? IO_WQ_ACCT_UNBOUND : IO_WQ_ACCT_BOUND;
io_wqe_dec_running(worker);
- if (work_bound) {
- worker->flags |= IO_WORKER_F_BOUND;
- wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers--;
- wqe->acct[IO_WQ_ACCT_BOUND].nr_workers++;
- } else {
- worker->flags &= ~IO_WORKER_F_BOUND;
- wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers++;
- wqe->acct[IO_WQ_ACCT_BOUND].nr_workers--;
- }
+ worker->flags ^= IO_WORKER_F_BOUND;
+ wqe->acct[index].nr_workers--;
+ wqe->acct[index ^ 1].nr_workers++;
io_wqe_inc_running(worker);
}
}
--
1.8.3.1
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH v4] io-wq: simplify code in __io_worker_busy
2021-04-06 3:08 ` [PATCH v4] " Hao Xu
@ 2021-04-06 15:36 ` Jens Axboe
2021-04-07 18:28 ` Pavel Begunkov
1 sibling, 0 replies; 10+ messages in thread
From: Jens Axboe @ 2021-04-06 15:36 UTC (permalink / raw)
To: Hao Xu; +Cc: io-uring, Pavel Begunkov, Joseph Qi
On 4/5/21 9:08 PM, Hao Xu wrote:
> leverage xor to simplify code in __io_worker_busy
Applied, thanks.
--
Jens Axboe
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v4] io-wq: simplify code in __io_worker_busy
2021-04-06 3:08 ` [PATCH v4] " Hao Xu
2021-04-06 15:36 ` Jens Axboe
@ 2021-04-07 18:28 ` Pavel Begunkov
1 sibling, 0 replies; 10+ messages in thread
From: Pavel Begunkov @ 2021-04-07 18:28 UTC (permalink / raw)
To: Hao Xu, Jens Axboe; +Cc: io-uring, Joseph Qi
On 06/04/2021 04:08, Hao Xu wrote:
> leverage xor to simplify code in __io_worker_busy
>
> Signed-off-by: Hao Xu <[email protected]>
> ---
>
> Sorry, typo by mistake...
>
> fs/io-wq.c | 15 ++++++---------
> 1 file changed, 6 insertions(+), 9 deletions(-)
>
> diff --git a/fs/io-wq.c b/fs/io-wq.c
> index 2dd2d4b1e538..fa2383cb4d50 100644
> --- a/fs/io-wq.c
> +++ b/fs/io-wq.c
> @@ -329,6 +329,8 @@ static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
> {
> bool worker_bound, work_bound;
>
> + BUILD_BUG_ON((IO_WQ_ACCT_UNBOUND ^ IO_WQ_ACCT_BOUND) != 1);
> +
> if (worker->flags & IO_WORKER_F_FREE) {
> worker->flags &= ~IO_WORKER_F_FREE;
> hlist_nulls_del_init_rcu(&worker->nulls_node);
> @@ -341,16 +343,11 @@ static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
> worker_bound = (worker->flags & IO_WORKER_F_BOUND) != 0;
> work_bound = (work->flags & IO_WQ_WORK_UNBOUND) == 0;
> if (worker_bound != work_bound) {
> + int index = work_bound ? IO_WQ_ACCT_UNBOUND : IO_WQ_ACCT_BOUND;
Jens, if you'll be at it, can you fold in \n here?
Let's keep static analysis happy
> io_wqe_dec_running(worker);
> - if (work_bound) {
> - worker->flags |= IO_WORKER_F_BOUND;
> - wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers--;
> - wqe->acct[IO_WQ_ACCT_BOUND].nr_workers++;
> - } else {
> - worker->flags &= ~IO_WORKER_F_BOUND;
> - wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers++;
> - wqe->acct[IO_WQ_ACCT_BOUND].nr_workers--;
> - }
> + worker->flags ^= IO_WORKER_F_BOUND;
> + wqe->acct[index].nr_workers--;
> + wqe->acct[index ^ 1].nr_workers++;
> io_wqe_inc_running(worker);
> }
> }
>
--
Pavel Begunkov
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v2] io-wq: simplify code in __io_worker_busy
2021-04-02 10:38 ` Pavel Begunkov
2021-04-04 19:17 ` Jens Axboe
@ 2021-04-05 7:36 ` Hao Xu
1 sibling, 0 replies; 10+ messages in thread
From: Hao Xu @ 2021-04-05 7:36 UTC (permalink / raw)
To: Jens Axboe; +Cc: io-uring, Pavel Begunkov, Joseph Qi
leverage xor to simplify code in __io_worker_busy
Signed-off-by: Hao Xu <[email protected]>
---
I thought about [IO_WQ_ACCT_UNBOUND + IO_WQ_ACCT_BOUND - index], but it
is not antithetical, so I finally choose to calculate two indexes
respectively.
fs/io-wq.c | 14 +++++---------
1 file changed, 5 insertions(+), 9 deletions(-)
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 433c4d3c3c1c..7ec2948838ca 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -292,16 +292,12 @@ static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker,
worker_bound = (worker->flags & IO_WORKER_F_BOUND) != 0;
work_bound = (work->flags & IO_WQ_WORK_UNBOUND) == 0;
if (worker_bound != work_bound) {
+ int index0 = work_bound ? IO_WQ_ACCT_UNBOUND : IO_WQ_ACCT_BOUND;
+ int index1 = work_bound ? IO_WQ_ACCT_BOUND : IO_WQ_ACCT_UNBOUND;
io_wqe_dec_running(worker);
- if (work_bound) {
- worker->flags |= IO_WORKER_F_BOUND;
- wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers--;
- wqe->acct[IO_WQ_ACCT_BOUND].nr_workers++;
- } else {
- worker->flags &= ~IO_WORKER_F_BOUND;
- wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers++;
- wqe->acct[IO_WQ_ACCT_BOUND].nr_workers--;
- }
+ worker->flags ^= IO_WORKER_F_BOUND;
+ wqe->acct[index0].nr_workers--;
+ wqe->acct[index1].nr_workers++;
io_wqe_inc_running(worker);
}
}
--
1.8.3.1
^ permalink raw reply related [flat|nested] 10+ messages in thread
end of thread, other threads:[~2021-04-07 18:32 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2021-04-02 10:18 [PATCH] io-wq: simplify code in __io_worker_busy Hao Xu
2021-04-02 10:38 ` Pavel Begunkov
2021-04-04 19:17 ` Jens Axboe
2021-04-05 7:53 ` [PATCH v3] " Hao Xu
2021-04-05 21:46 ` Jens Axboe
2021-04-06 2:18 ` Hao Xu
2021-04-06 3:08 ` [PATCH v4] " Hao Xu
2021-04-06 15:36 ` Jens Axboe
2021-04-07 18:28 ` Pavel Begunkov
2021-04-05 7:36 ` [PATCH v2] " Hao Xu
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