2013-09-09 05:10:18

by Li Bin

Subject: [PATCH] workqueue: remove meaningless BUILD_BUG_ON() in init_workqueues()

From: Li Bin <[email protected]>

In the current implementation, this BUILD_BUG_ON makes no sense.
First of all, the number of worker pools needed cannot be determined
at compile time, because the number of backing pools for UNBOUND
workqueues is dynamic based on the assigned custom attributes.
Secondly, it should use WORK_OFFQ_POOL_BITS instead of
(BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT).

Signed-off-by: Li Bin <[email protected]>
---
kernel/workqueue.c | 4 ----
1 file changed, 4 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 987293d..41019b1 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -5009,10 +5009,6 @@ static int __init init_workqueues(void)
int std_nice[NR_STD_WORKER_POOLS] = { 0, HIGHPRI_NICE_LEVEL };
int i, cpu;

- /* make sure we have enough bits for OFFQ pool ID */
- BUILD_BUG_ON((1LU << (BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT)) <
- WORK_CPU_END * NR_STD_WORKER_POOLS);
-
WARN_ON(__alignof__(struct pool_workqueue) < __alignof__(long long));

pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC);
--
1.8.2.1

2013-09-09 14:13:09

by Tejun Heo

Subject: Re: [PATCH] workqueue: remove meaningless BUILD_BUG_ON() in init_workqueues()

Hello, Libin.

On Mon, Sep 09, 2013 at 01:10:00PM +0800, Libin wrote:
> From: Li Bin <[email protected]>
>
> In the current implementation, this BUILD_BUG_ON makes no sense.
> First of all, the number of worker pools needed cannot be determined
> at compile time, because the number of backing pools for UNBOUND
> workqueues is dynamic based on the assigned custom attributes.
> Secondly, it should use WORK_OFFQ_POOL_BITS instead of
> (BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT).
>
> Signed-off-by: Li Bin <[email protected]>
> ---
> kernel/workqueue.c | 4 ----
> 1 file changed, 4 deletions(-)
>
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index 987293d..41019b1 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -5009,10 +5009,6 @@ static int __init init_workqueues(void)
> int std_nice[NR_STD_WORKER_POOLS] = { 0, HIGHPRI_NICE_LEVEL };
> int i, cpu;
>
> - /* make sure we have enough bits for OFFQ pool ID */
> - BUILD_BUG_ON((1LU << (BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT)) <
> - WORK_CPU_END * NR_STD_WORKER_POOLS);
> -

Indeed, but can you please update worker_pool_assign_id() so that it
doesn't allocate ids >= WORK_OFFQ_POOL_NONE?

Thanks.

--
tejun

2013-09-09 14:18:25

by Tejun Heo

Subject: Re: [PATCH] workqueue: remove meaningless BUILD_BUG_ON() in init_workqueues()

On Mon, Sep 09, 2013 at 10:13:02AM -0400, Tejun Heo wrote:
> Indeed, but can you please update worker_pool_assign_id() so that it
> doesn't allocate ids >= WORK_OFFQ_POOL_NONE?

So, you did this separately on the next patch. Can you please roll
that patch into this one with the suggested update?

Thanks.

--
tejun

2013-09-10 00:26:22

by Li Bin

Subject: Re: [PATCH] workqueue: remove meaningless BUILD_BUG_ON() in init_workqueues()

On 2013/9/9 22:18, Tejun Heo wrote:
> On Mon, Sep 09, 2013 at 10:13:02AM -0400, Tejun Heo wrote:
>> Indeed, but can you please update worker_pool_assign_id() so that it
>> doesn't allocate ids >= WORK_OFFQ_POOL_NONE?
>
> So, you did this separately on the next patch. Can you please roll
> that patch into this one with the suggested update?

Hello Tejun,
I will update it according to your suggestion.

Thanks!
Libin

>
> Thanks.
>