Messages in this thread | | | Date | Tue, 27 Feb 2024 17:15:07 +0100 | From | Frederic Weisbecker <> | Subject | Re: [PATCH v5 2/4] rcu: Reduce synchronize_rcu() latency |
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Le Tue, Feb 20, 2024 at 07:31:13PM +0100, Uladzislau Rezki (Sony) a écrit : > +static struct llist_node *rcu_sr_get_wait_head(void) > +{ > + struct sr_wait_node *sr_wn; > + int i; > + > + for (i = 0; i < SR_NORMAL_GP_WAIT_HEAD_MAX; i++) { > + sr_wn = &(rcu_state.srs_wait_nodes)[i]; > + > + if (!atomic_cmpxchg_acquire(&sr_wn->inuse, 0, 1)) > + return &sr_wn->node; > + } > + > + return NULL; > +} > + > +static void rcu_sr_put_wait_head(struct llist_node *node) > +{ > + struct sr_wait_node *sr_wn = container_of(node, struct sr_wait_node, node); > + atomic_set_release(&sr_wn->inuse, 0);
Can we comment this release/acquire pair?
IIUC, the point is that we must make sure that the wait_head->next fetch happens before it gets reused and rewritten to something else.
Thanks.
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