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Merge branch 'for-4.13-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

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Pull workqueue fixes from Tejun Heo:
 "Two notable fixes.

   - While adding NUMA affinity support to unbound workqueues, the
     assumption that an unbound workqueue with max_active == 1 is
     ordered was broken.

     The plan was to use explicit alloc_ordered_workqueue() for those
     cases. Unfortunately, I forgot to update the documentation properly
     and we grew a handful of use cases which depend on that assumption.

     While we want to convert them to alloc_ordered_workqueue(), we
     don't really lose anything by enforcing ordered execution on
     unbound max_active == 1 workqueues and it doesn't make sense to
     risk subtle bugs. Restore the assumption.

   - Workqueue assumes that CPU <-> NUMA node mapping remains static.

     This is a general assumption - we don't have any synchronization
     mechanism around CPU <-> node mapping. Unfortunately, powerpc may
     change the mapping dynamically leading to crashes. Michael added a
     workaround so that we at least don't crash while powerpc hotplug
     code gets updated"

* 'for-4.13-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: Work around edge cases for calc of pool's cpumask
  workqueue: implicit ordered attribute should be overridable
  workqueue: restore WQ_UNBOUND/max_active==1 to be ordered
This commit is contained in:
Linus Torvalds
2017-07-31 13:37:28 -07:00
parent 3dcc4c7d42 1ad0f0a7aa
commit ff2620f778
2 changed files with 29 additions and 5 deletions
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4
include/linux/workqueue.h
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@@ -323,6 +323,7 @@ enum {
__WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */
__WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */
__WQ_ORDERED_EXPLICIT = 1 << 18, /* internal: alloc_ordered_workqueue() */
__WQ_LEGACY = 1 << 18, /* internal: create*_workqueue() */
WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
@@ -422,7 +423,8 @@ __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
* Pointer to the allocated workqueue on success, %NULL on failure.
*/
#define alloc_ordered_workqueue(fmt, flags, args...) \
alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | \
__WQ_ORDERED_EXPLICIT | (flags), 1, ##args)
#define create_workqueue(name) \
alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name))