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Diffstat (limited to 'Documentation/core-api/workqueue.rst')
| -rw-r--r-- | Documentation/core-api/workqueue.rst | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/Documentation/core-api/workqueue.rst b/Documentation/core-api/workqueue.rst index bcc370c876be..e295835fc116 100644 --- a/Documentation/core-api/workqueue.rst +++ b/Documentation/core-api/workqueue.rst @@ -245,8 +245,8 @@ CPU which can be assigned to the work items of a wq. For example, with at the same time per CPU. This is always a per-CPU attribute, even for unbound workqueues. -The maximum limit for ``@max_active`` is 512 and the default value used -when 0 is specified is 256. These values are chosen sufficiently high +The maximum limit for ``@max_active`` is 2048 and the default value used +when 0 is specified is 1024. These values are chosen sufficiently high such that they are not the limiting factor while providing protection in runaway cases. @@ -260,7 +260,7 @@ Some users depend on strict execution ordering where only one work item is in flight at any given time and the work items are processed in queueing order. While the combination of ``@max_active`` of 1 and ``WQ_UNBOUND`` used to achieve this behavior, this is no longer the -case. Use ``alloc_ordered_queue()`` instead. +case. Use alloc_ordered_workqueue() instead. Example Execution Scenarios @@ -357,6 +357,11 @@ Guidelines difference in execution characteristics between using a dedicated wq and a system wq. + Note: If something may generate more than @max_active outstanding + work items (do stress test your producers), it may saturate a system + wq and potentially lead to deadlock. It should utilize its own + dedicated workqueue rather than the system wq. + * Unless work items are expected to consume a huge amount of CPU cycles, using a bound wq is usually beneficial due to the increased level of locality in wq operations and work item execution. |