| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | #include "rrdcollector.h" |
| 4 | #include "rrdcollector-internals.h" |
| 5 | |
| 6 | // Each function points to this collector structure |
| 7 | // so that when the collector exits, all of them will |
| 8 | // be invalidated (running == false) |
| 9 | // The last function using this collector |
| 10 | // frees the structure too (or when the collector calls |
| 11 | // rrdset_collector_finished()). |
| 12 | |
| 13 | struct rrd_collector { |
| 14 | REFCOUNT refcount; |
| 15 | REFCOUNT refcount_dispatcher; |
| 16 | pid_t tid; |
| 17 | bool running; |
| 18 | }; |
| 19 | |
| 20 | // Each thread that adds RRDSET functions has to call |
| 21 | // rrdset_collector_started() and rrdset_collector_finished() |
| 22 | // to create the collector structure. |
| 23 | |
| 24 | __thread struct rrd_collector *thread_rrd_collector = NULL; |
| 25 | |
| 26 | inline bool rrd_collector_running(struct rrd_collector *rdc) { |
| 27 | return __atomic_load_n(&rdc->running, __ATOMIC_RELAXED); |
| 28 | } |
| 29 | |
| 30 | inline pid_t rrd_collector_tid(struct rrd_collector *rdc) { |
| 31 | return rdc->tid; |
| 32 | } |
| 33 | |
| 34 | bool rrd_collector_dispatcher_acquire(struct rrd_collector *rdc) { |
| 35 | return refcount_acquire(&rdc->refcount_dispatcher); |
| 36 | } |
| 37 | |
| 38 | void rrd_collector_dispatcher_release(struct rrd_collector *rdc) { |
| 39 | refcount_release(&rdc->refcount_dispatcher); |
| 40 | } |
| 41 | |
| 42 | static void rrd_collector_free(struct rrd_collector *rdc) { |
| 43 | if(rrd_collector_running(rdc) || !refcount_acquire_for_deletion(&rdc->refcount)) |
| 44 | // the collector is still referenced by charts. |
| 45 | // leave it hanging there, the last chart will actually free it. |
| 46 | return; |
| 47 | |
| 48 | // we can free it now |
| 49 | freez(rdc); |
| 50 | } |
| 51 | |
| 52 | // called once per collector |
| 53 | void rrd_collector_started(void) { |
| 54 | if(!thread_rrd_collector) |
| 55 | thread_rrd_collector = callocz(1, sizeof(struct rrd_collector)); |
| 56 | |
| 57 | thread_rrd_collector->tid = gettid_cached(); |
| 58 | __atomic_store_n(&thread_rrd_collector->running, true, __ATOMIC_RELAXED); |
| 59 | } |
| 60 | |
| 61 | // called once per collector |
| 62 | void rrd_collector_finished(void) { |
| 63 | if(!thread_rrd_collector) |
| 64 | return; |
| 65 | |
| 66 | __atomic_store_n(&thread_rrd_collector->running, false, __ATOMIC_RELAXED); |
| 67 | |
| 68 | // wait for any cancellation requests to be dispatched; |
| 69 | // the problem is that cancellation requests require a structure allocated by the collector, |
| 70 | // so, while cancellation requests are being dispatched, this structure is accessed. |
| 71 | // delaying the exit of the thread is required to avoid cleaning up this structure. |
| 72 | |
| 73 | while(!refcount_acquire_for_deletion(&thread_rrd_collector->refcount_dispatcher)) |
| 74 | sleep_usec(1 * USEC_PER_MS); |
| 75 | |
| 76 | rrd_collector_free(thread_rrd_collector); |
| 77 | thread_rrd_collector = NULL; |
| 78 | } |
| 79 | |
| 80 | static bool rrd_collector_acquire(struct rrd_collector *rdc) { |
| 81 | if(!rdc || !rrd_collector_running(rdc)) |
| 82 | return false; |
| 83 | |
| 84 | return refcount_acquire(&rdc->refcount); |
| 85 | } |
| 86 | |
| 87 | struct rrd_collector *rrd_collector_acquire_current_thread(void) { |
| 88 | rrd_collector_started(); |
| 89 | |
| 90 | if(!rrd_collector_acquire(thread_rrd_collector)) |
| 91 | internal_fatal(true, "FUNCTIONS: Trying to acquire a the current thread collector, that is currently exiting."); |
| 92 | |
| 93 | return thread_rrd_collector; |
| 94 | } |
| 95 | |
| 96 | void rrd_collector_release(struct rrd_collector *rdc) { |
| 97 | if(unlikely(!rdc)) return; |
| 98 | |
| 99 | if(refcount_release(&rdc->refcount) == 0) |
| 100 | rrd_collector_free(rdc); |
| 101 | } |