diff options
Diffstat (limited to 'fs/jbd2')
| -rw-r--r-- | fs/jbd2/checkpoint.c | 147 | ||||
| -rw-r--r-- | fs/jbd2/journal.c | 87 |
2 files changed, 234 insertions, 0 deletions
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c index 75a4f622afaf..1abdae44a3d8 100644 --- a/fs/jbd2/checkpoint.c +++ b/fs/jbd2/checkpoint.c @@ -80,6 +80,18 @@ static inline void __buffer_relink_io(struct journal_head *jh) } /* + * Check a checkpoint buffer could be release or not. + * + * Requires j_list_lock + */ +static inline bool __cp_buffer_busy(struct journal_head *jh) +{ + struct buffer_head *bh = jh2bh(jh); + + return (jh->b_transaction || buffer_locked(bh) || buffer_dirty(bh)); +} + +/* * Try to release a checkpointed buffer from its transaction. * Returns 1 if we released it and 2 if we also released the * whole transaction. @@ -459,6 +471,137 @@ static int journal_clean_one_cp_list(struct journal_head *jh, bool destroy) } /* + * journal_shrink_one_cp_list + * + * Find 'nr_to_scan' written-back checkpoint buffers in the given list + * and try to release them. If the whole transaction is released, set + * the 'released' parameter. Return the number of released checkpointed + * buffers. + * + * Called with j_list_lock held. + */ +static unsigned long journal_shrink_one_cp_list(struct journal_head *jh, + unsigned long *nr_to_scan, + bool *released) +{ + struct journal_head *last_jh; + struct journal_head *next_jh = jh; + unsigned long nr_freed = 0; + int ret; + + if (!jh || *nr_to_scan == 0) + return 0; + + last_jh = jh->b_cpprev; + do { + jh = next_jh; + next_jh = jh->b_cpnext; + + (*nr_to_scan)--; + if (__cp_buffer_busy(jh)) + continue; + + nr_freed++; + ret = __jbd2_journal_remove_checkpoint(jh); + if (ret) { + *released = true; + break; + } + + if (need_resched()) + break; + } while (jh != last_jh && *nr_to_scan); + + return nr_freed; +} + +/* + * jbd2_journal_shrink_checkpoint_list + * + * Find 'nr_to_scan' written-back checkpoint buffers in the journal + * and try to release them. Return the number of released checkpointed + * buffers. + * + * Called with j_list_lock held. + */ +unsigned long jbd2_journal_shrink_checkpoint_list(journal_t *journal, + unsigned long *nr_to_scan) +{ + transaction_t *transaction, *last_transaction, *next_transaction; + bool released; + tid_t first_tid = 0, last_tid = 0, next_tid = 0; + tid_t tid = 0; + unsigned long nr_freed = 0; + unsigned long nr_scanned = *nr_to_scan; + +again: + spin_lock(&journal->j_list_lock); + if (!journal->j_checkpoint_transactions) { + spin_unlock(&journal->j_list_lock); + goto out; + } + + /* + * Get next shrink transaction, resume previous scan or start + * over again. If some others do checkpoint and drop transaction + * from the checkpoint list, we ignore saved j_shrink_transaction + * and start over unconditionally. + */ + if (journal->j_shrink_transaction) + transaction = journal->j_shrink_transaction; + else + transaction = journal->j_checkpoint_transactions; + + if (!first_tid) + first_tid = transaction->t_tid; + last_transaction = journal->j_checkpoint_transactions->t_cpprev; + next_transaction = transaction; + last_tid = last_transaction->t_tid; + do { + transaction = next_transaction; + next_transaction = transaction->t_cpnext; + tid = transaction->t_tid; + released = false; + + nr_freed += journal_shrink_one_cp_list(transaction->t_checkpoint_list, + nr_to_scan, &released); + if (*nr_to_scan == 0) + break; + if (need_resched() || spin_needbreak(&journal->j_list_lock)) + break; + if (released) + continue; + + nr_freed += journal_shrink_one_cp_list(transaction->t_checkpoint_io_list, + nr_to_scan, &released); + if (*nr_to_scan == 0) + break; + if (need_resched() || spin_needbreak(&journal->j_list_lock)) + break; + } while (transaction != last_transaction); + + if (transaction != last_transaction) { + journal->j_shrink_transaction = next_transaction; + next_tid = next_transaction->t_tid; + } else { + journal->j_shrink_transaction = NULL; + next_tid = 0; + } + + spin_unlock(&journal->j_list_lock); + cond_resched(); + + if (*nr_to_scan && next_tid) + goto again; +out: + nr_scanned -= *nr_to_scan; + trace_jbd2_shrink_checkpoint_list(journal, first_tid, tid, last_tid, + nr_freed, nr_scanned, next_tid); + + return nr_freed; +} + +/* * journal_clean_checkpoint_list * * Find all the written-back checkpoint buffers in the journal and release them. @@ -580,6 +723,7 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh) __buffer_unlink(jh); jh->b_cp_transaction = NULL; + percpu_counter_dec(&journal->j_jh_shrink_count); jbd2_journal_put_journal_head(jh); /* Is this transaction empty? */ @@ -642,6 +786,7 @@ void __jbd2_journal_insert_checkpoint(struct journal_head *jh, jh->b_cpnext->b_cpprev = jh; } transaction->t_checkpoint_list = jh; + percpu_counter_inc(&transaction->t_journal->j_jh_shrink_count); } /* @@ -657,6 +802,8 @@ void __jbd2_journal_insert_checkpoint(struct journal_head *jh, void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transaction) { assert_spin_locked(&journal->j_list_lock); + + journal->j_shrink_transaction = NULL; if (transaction->t_cpnext) { transaction->t_cpnext->t_cpprev = transaction->t_cpprev; transaction->t_cpprev->t_cpnext = transaction->t_cpnext; diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 8b3f5bbd65f9..7c52feb6f753 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -2051,6 +2051,91 @@ recovery_error: } /** + * jbd2_journal_shrink_scan() + * + * Scan the checkpointed buffer on the checkpoint list and release the + * journal_head. + */ +static unsigned long jbd2_journal_shrink_scan(struct shrinker *shrink, + struct shrink_control *sc) +{ + journal_t *journal = container_of(shrink, journal_t, j_shrinker); + unsigned long nr_to_scan = sc->nr_to_scan; + unsigned long nr_shrunk; + unsigned long count; + + count = percpu_counter_read_positive(&journal->j_jh_shrink_count); + trace_jbd2_shrink_scan_enter(journal, sc->nr_to_scan, count); + + nr_shrunk = jbd2_journal_shrink_checkpoint_list(journal, &nr_to_scan); + + count = percpu_counter_read_positive(&journal->j_jh_shrink_count); + trace_jbd2_shrink_scan_exit(journal, nr_to_scan, nr_shrunk, count); + + return nr_shrunk; +} + +/** + * jbd2_journal_shrink_count() + * + * Count the number of checkpoint buffers on the checkpoint list. + */ +static unsigned long jbd2_journal_shrink_count(struct shrinker *shrink, + struct shrink_control *sc) +{ + journal_t *journal = container_of(shrink, journal_t, j_shrinker); + unsigned long count; + + count = percpu_counter_read_positive(&journal->j_jh_shrink_count); + trace_jbd2_shrink_count(journal, sc->nr_to_scan, count); + + return count; +} + +/** + * jbd2_journal_register_shrinker() + * @journal: Journal to act on. + * + * Init a percpu counter to record the checkpointed buffers on the checkpoint + * list and register a shrinker to release their journal_head. + */ +int jbd2_journal_register_shrinker(journal_t *journal) +{ + int err; + + journal->j_shrink_transaction = NULL; + + err = percpu_counter_init(&journal->j_jh_shrink_count, 0, GFP_KERNEL); + if (err) + return err; + + journal->j_shrinker.scan_objects = jbd2_journal_shrink_scan; + journal->j_shrinker.count_objects = jbd2_journal_shrink_count; + journal->j_shrinker.seeks = DEFAULT_SEEKS; + journal->j_shrinker.batch = journal->j_max_transaction_buffers; + + err = register_shrinker(&journal->j_shrinker); + if (err) { + percpu_counter_destroy(&journal->j_jh_shrink_count); + return err; + } + + return 0; +} + +/** + * jbd2_journal_unregister_shrinker() + * @journal: Journal to act on. + * + * Unregister the checkpointed buffer shrinker and destroy the percpu counter. + */ +void jbd2_journal_unregister_shrinker(journal_t *journal) +{ + percpu_counter_destroy(&journal->j_jh_shrink_count); + unregister_shrinker(&journal->j_shrinker); +} + +/** * jbd2_journal_destroy() - Release a journal_t structure. * @journal: Journal to act on. * @@ -2122,6 +2207,8 @@ int jbd2_journal_destroy(journal_t *journal) brelse(journal->j_sb_buffer); } + jbd2_journal_unregister_shrinker(journal); + if (journal->j_proc_entry) jbd2_stats_proc_exit(journal); iput(journal->j_inode); |