Re: [PATCH 1/9] workqueue: mark WQ_NON_REENTRANT deprecated
On 07/30/2013 08:40 PM, Tejun Heo wrote:
> dbf2576e37 ("workqueue: make all workqueues non-reentrant") made
> WQ_NON_REENTRANT no-op but the following patches didn't remove the
> flag or update the documentation. Let's mark the flag deprecated and
> update the documentation accordingly.
>
> Signed-off-by: Tejun Heo
Acked-by: Lai Jiangshan
> ---
> Documentation/workqueue.txt | 18 ++
> include/linux/workqueue.h | 7 ++-
> 2 files changed, 12 insertions(+), 13 deletions(-)
>
> diff --git a/Documentation/workqueue.txt b/Documentation/workqueue.txt
> index a6ab4b6..67113f6 100644
> --- a/Documentation/workqueue.txt
> +++ b/Documentation/workqueue.txt
> @@ -100,8 +100,8 @@ Subsystems and drivers can create and queue work items
> through special
> workqueue API functions as they see fit. They can influence some
> aspects of the way the work items are executed by setting flags on the
> workqueue they are putting the work item on. These flags include
> -things like CPU locality, reentrancy, concurrency limits, priority and
> -more. To get a detailed overview refer to the API description of
> +things like CPU locality, concurrency limits, priority and more. To
> +get a detailed overview refer to the API description of
> alloc_workqueue() below.
>
> When a work item is queued to a workqueue, the target gcwq and
> @@ -166,16 +166,6 @@ resources, scheduled and executed.
>
> @flags:
>
> - WQ_NON_REENTRANT
> -
> - By default, a wq guarantees non-reentrance only on the same
> - CPU. A work item may not be executed concurrently on the same
> - CPU by multiple workers but is allowed to be executed
> - concurrently on multiple CPUs. This flag makes sure
> - non-reentrance is enforced across all CPUs. Work items queued
> - to a non-reentrant wq are guaranteed to be executed by at most
> - one worker system-wide at any given time.
> -
>WQ_UNBOUND
>
> Work items queued to an unbound wq are served by a special
> @@ -233,6 +223,10 @@ resources, scheduled and executed.
>
> This flag is meaningless for unbound wq.
>
> +Note that the flag WQ_NON_REENTRANT no longer exists as all workqueues
> +are now non-reentrant - any work item is guaranteed to be executed by
> +at most one worker system-wide at any given time.
> +
> @max_active:
>
> @max_active determines the maximum number of execution contexts per
> diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
> index a0ed78a..594521b 100644
> --- a/include/linux/workqueue.h
> +++ b/include/linux/workqueue.h
> @@ -295,7 +295,12 @@ static inline unsigned int work_static(struct
> work_struct *work) { return 0; }
> * Documentation/workqueue.txt.
> */
> enum {
> - WQ_NON_REENTRANT= 1 << 0, /* guarantee non-reentrance */
> + /*
> + * All wqs are now non-reentrant making the following flag
> + * meaningless. Will be removed.
> + */
> + WQ_NON_REENTRANT= 1 << 0, /* DEPRECATED */
> +
> WQ_UNBOUND = 1 << 1, /* not bound to any cpu */
> WQ_FREEZABLE= 1 << 2, /* freeze during suspend */
> WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */
--
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Re: [PATCH 1/9] workqueue: mark WQ_NON_REENTRANT deprecated
On 07/30/2013 08:40 PM, Tejun Heo wrote:
dbf2576e37 (workqueue: make all workqueues non-reentrant) made
WQ_NON_REENTRANT no-op but the following patches didn't remove the
flag or update the documentation. Let's mark the flag deprecated and
update the documentation accordingly.
Signed-off-by: Tejun Heo t...@kernel.org
Acked-by: Lai Jiangshan la...@cn.fujitsu.com
---
Documentation/workqueue.txt | 18 ++
include/linux/workqueue.h | 7 ++-
2 files changed, 12 insertions(+), 13 deletions(-)
diff --git a/Documentation/workqueue.txt b/Documentation/workqueue.txt
index a6ab4b6..67113f6 100644
--- a/Documentation/workqueue.txt
+++ b/Documentation/workqueue.txt
@@ -100,8 +100,8 @@ Subsystems and drivers can create and queue work items
through special
workqueue API functions as they see fit. They can influence some
aspects of the way the work items are executed by setting flags on the
workqueue they are putting the work item on. These flags include
-things like CPU locality, reentrancy, concurrency limits, priority and
-more. To get a detailed overview refer to the API description of
+things like CPU locality, concurrency limits, priority and more. To
+get a detailed overview refer to the API description of
alloc_workqueue() below.
When a work item is queued to a workqueue, the target gcwq and
@@ -166,16 +166,6 @@ resources, scheduled and executed.
@flags:
- WQ_NON_REENTRANT
-
- By default, a wq guarantees non-reentrance only on the same
- CPU. A work item may not be executed concurrently on the same
- CPU by multiple workers but is allowed to be executed
- concurrently on multiple CPUs. This flag makes sure
- non-reentrance is enforced across all CPUs. Work items queued
- to a non-reentrant wq are guaranteed to be executed by at most
- one worker system-wide at any given time.
-
WQ_UNBOUND
Work items queued to an unbound wq are served by a special
@@ -233,6 +223,10 @@ resources, scheduled and executed.
This flag is meaningless for unbound wq.
+Note that the flag WQ_NON_REENTRANT no longer exists as all workqueues
+are now non-reentrant - any work item is guaranteed to be executed by
+at most one worker system-wide at any given time.
+
@max_active:
@max_active determines the maximum number of execution contexts per
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index a0ed78a..594521b 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -295,7 +295,12 @@ static inline unsigned int work_static(struct
work_struct *work) { return 0; }
* Documentation/workqueue.txt.
*/
enum {
- WQ_NON_REENTRANT= 1 0, /* guarantee non-reentrance */
+ /*
+ * All wqs are now non-reentrant making the following flag
+ * meaningless. Will be removed.
+ */
+ WQ_NON_REENTRANT= 1 0, /* DEPRECATED */
+
WQ_UNBOUND = 1 1, /* not bound to any cpu */
WQ_FREEZABLE= 1 2, /* freeze during suspend */
WQ_MEM_RECLAIM = 1 3, /* may be used for memory reclaim */
--
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