mirror of
https://gitlab.nic.cz/labs/bird.git
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e91754f5b9
In multithreaded environment, we need to pass messages between workers. This is done by queuing events to their respective queues. The double-linked list is not really useful for that as it needs locking everywhere. This commit rewrites the event subsystem to use a single-linked list where events are enqueued by a single atomic instruction and the queue is processed after atomically moving the whole queue aside.
63 lines
2.1 KiB
C
63 lines
2.1 KiB
C
/*
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* BIRD Library -- Locking
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*
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* (c) 2020--2021 Maria Matejka <mq@jmq.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#ifndef _BIRD_LOCKING_H_
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#define _BIRD_LOCKING_H_
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struct domain_generic;
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/* Here define the global lock order; first to last. */
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struct lock_order {
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struct domain_generic *the_bird;
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struct domain_generic *proto;
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struct domain_generic *rtable;
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};
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extern _Thread_local struct lock_order locking_stack;
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extern _Thread_local struct domain_generic **last_locked;
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#define DOMAIN(type) struct domain__##type
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#define DEFINE_DOMAIN(type) DOMAIN(type) { struct domain_generic *type; }
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#define DOMAIN_ORDER(type) OFFSETOF(struct lock_order, type)
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#define DOMAIN_NEW(type, name) (DOMAIN(type)) { .type = domain_new(name, DOMAIN_ORDER(type)) }
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struct domain_generic *domain_new(const char *name, uint order);
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#define DOMAIN_FREE(type, d) domain_free((d).type)
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void domain_free(struct domain_generic *);
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#define DOMAIN_NULL(type) (DOMAIN(type)) {}
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#define LOCK_DOMAIN(type, d) do_lock(((d).type), &(locking_stack.type))
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#define UNLOCK_DOMAIN(type, d) do_unlock(((d).type), &(locking_stack.type))
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#define DOMAIN_IS_LOCKED(type, d) (((d).type) == (locking_stack.type))
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#define DG_IS_LOCKED(d) ((d) == *(DG_LSP(d)))
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/* Internal for locking */
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void do_lock(struct domain_generic *dg, struct domain_generic **lsp);
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void do_unlock(struct domain_generic *dg, struct domain_generic **lsp);
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uint dg_order(struct domain_generic *dg);
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#define DG_LSP(d) ((struct domain_generic **) (((void *) &locking_stack) + dg_order(d)))
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#define DG_LOCK(d) do_lock(d, DG_LSP(d))
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#define DG_UNLOCK(d) do_unlock(d, DG_LSP(d))
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/* Use with care. To be removed in near future. */
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DEFINE_DOMAIN(the_bird);
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extern DOMAIN(the_bird) the_bird_domain;
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#define the_bird_lock() LOCK_DOMAIN(the_bird, the_bird_domain)
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#define the_bird_unlock() UNLOCK_DOMAIN(the_bird, the_bird_domain)
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#define the_bird_locked() DOMAIN_IS_LOCKED(the_bird, the_bird_domain)
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#define ASSERT_THE_BIRD_LOCKED ({ if (!the_bird_locked()) bug("The BIRD lock must be locked here: %s:%d", __FILE__, __LINE__); })
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#endif
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