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3741 zfs needs better comments
Submitted by:   Will Andrews <willa@spectralogic.com>
Submitted by:   Justin Gibbs <justing@spectralogic.com>
Submitted by:   Alan Somers <alans@spectralogic.com>
Reviewed by:    Matthew Ahrens <mahrens@delphix.com>

*** 335,344 **** --- 335,352 ---- mutex_exit(&tc->tc_lock); th->th_cpu = NULL; /* defensive */ } + /* + * Quiesce, v.: to render temporarily inactive or disabled + * + * Blocks until all transactions in the group are committed. + * + * On return, the transaction group has reached a stable state in which it can + * then be passed off to the syncing context. + */ static void txg_quiesce(dsl_pool_t *dp, uint64_t txg) { tx_state_t *tx = &dp->dp_tx; int g = txg & TXG_MASK;
*** 385,405 **** kmem_free(cb_list, sizeof (list_t)); } /* * Dispatch the commit callbacks registered on this txg to worker threads. */ static void txg_dispatch_callbacks(dsl_pool_t *dp, uint64_t txg) { int c; tx_state_t *tx = &dp->dp_tx; list_t *cb_list; for (c = 0; c < max_ncpus; c++) { tx_cpu_t *tc = &tx->tx_cpu[c]; ! /* No need to lock tx_cpu_t at this point */ int g = txg & TXG_MASK; if (list_is_empty(&tc->tc_callbacks[g])) continue; --- 393,419 ---- kmem_free(cb_list, sizeof (list_t)); } /* * Dispatch the commit callbacks registered on this txg to worker threads. + * + * If no callbacks are registered for a given TXG, nothing happens. + * This function creates a taskq for the associated pool, if needed. */ static void txg_dispatch_callbacks(dsl_pool_t *dp, uint64_t txg) { int c; tx_state_t *tx = &dp->dp_tx; list_t *cb_list; for (c = 0; c < max_ncpus; c++) { tx_cpu_t *tc = &tx->tx_cpu[c]; ! /* ! * No need to lock tx_cpu_t at this point, since this can ! * only be called once a txg has been synced. ! */ int g = txg & TXG_MASK; if (list_is_empty(&tc->tc_callbacks[g])) continue;