Messages in this thread | | | Date | Thu, 15 Aug 2019 07:57:49 -0700 | From | Matthew Wilcox <> | Subject | Re: [PATCH v3 -rcu] workqueue: Convert for_each_wq to use built-in list check |
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On Thu, Aug 15, 2019 at 10:18:42AM -0400, Joel Fernandes (Google) wrote: > list_for_each_entry_rcu now has support to check for RCU reader sections > as well as lock. Just use the support in it, instead of explicitly > checking in the caller.
...
> #define assert_rcu_or_wq_mutex_or_pool_mutex(wq) \ > RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \ > !lockdep_is_held(&wq->mutex) && \
Can't you also get rid of this macro?
It's used in one place:
static struct pool_workqueue *unbound_pwq_by_node(struct workqueue_struct *wq, int node) { assert_rcu_or_wq_mutex_or_pool_mutex(wq);
/* * XXX: @node can be NUMA_NO_NODE if CPU goes offline while a * delayed item is pending. The plan is to keep CPU -> NODE * mapping valid and stable across CPU on/offlines. Once that * happens, this workaround can be removed. */ if (unlikely(node == NUMA_NO_NODE)) return wq->dfl_pwq;
return rcu_dereference_raw(wq->numa_pwq_tbl[node]); }
Shouldn't we delete that assert and use
+ return rcu_dereference_check(wq->numa_pwq_tbl[node], + lockdep_is_held(&wq->mutex) || + lockdep_is_held(&wq_pool_mutex));
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