On Tue 01-08-23 11:19:19, Greg Kroah-Hartman wrote: > From: Zhang Yi <yi.zhang@xxxxxxxxxx> > > [ Upstream commit b98dba273a0e47dbfade89c9af73c5b012a4eabb ] > > journal_clean_one_cp_list() and journal_shrink_one_cp_list() are almost > the same, so merge them into journal_shrink_one_cp_list(), remove the > nr_to_scan parameter, always scan and try to free the whole checkpoint > list. > > Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx> > Reviewed-by: Jan Kara <jack@xxxxxxx> > Link: https://lore.kernel.org/r/20230606135928.434610-4-yi.zhang@xxxxxxxxxxxxxxx > Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> > Stable-dep-of: 46f881b5b175 ("jbd2: fix a race when checking checkpoint buffer busy") > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> This and the following patch (46f881b5b175) have some issues [1] and cause a performance regression for some workloads and possible metadata corruption after a crash. So please drop these two patches from the stable trees for now. We can include them again later once the code has stabilized... Thanks! Honza [1] https://lore.kernel.org/all/20230714025528.564988-1-yi.zhang@xxxxxxxxxxxxxxx > fs/jbd2/checkpoint.c | 75 +++++++++---------------------------- > include/trace/events/jbd2.h | 12 ++---- > 2 files changed, 21 insertions(+), 66 deletions(-) > > diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c > index c1f543e86170a..ab72aeb766a74 100644 > --- a/fs/jbd2/checkpoint.c > +++ b/fs/jbd2/checkpoint.c > @@ -349,50 +349,10 @@ int jbd2_cleanup_journal_tail(journal_t *journal) > > /* Checkpoint list management */ > > -/* > - * journal_clean_one_cp_list > - * > - * Find all the written-back checkpoint buffers in the given list and > - * release them. If 'destroy' is set, clean all buffers unconditionally. > - * > - * Called with j_list_lock held. > - * Returns 1 if we freed the transaction, 0 otherwise. > - */ > -static int journal_clean_one_cp_list(struct journal_head *jh, bool destroy) > -{ > - struct journal_head *last_jh; > - struct journal_head *next_jh = jh; > - > - if (!jh) > - return 0; > - > - last_jh = jh->b_cpprev; > - do { > - jh = next_jh; > - next_jh = jh->b_cpnext; > - > - if (!destroy && __cp_buffer_busy(jh)) > - return 0; > - > - if (__jbd2_journal_remove_checkpoint(jh)) > - return 1; > - /* > - * This function only frees up some memory > - * if possible so we dont have an obligation > - * to finish processing. Bail out if preemption > - * requested: > - */ > - if (need_resched()) > - return 0; > - } while (jh != last_jh); > - > - return 0; > -} > - > /* > * journal_shrink_one_cp_list > * > - * Find 'nr_to_scan' written-back checkpoint buffers in the given list > + * Find all the 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. > @@ -400,15 +360,15 @@ static int journal_clean_one_cp_list(struct journal_head *jh, bool destroy) > * 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) > + bool destroy, 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) > + *released = false; > + if (!jh) > return 0; > > last_jh = jh->b_cpprev; > @@ -416,8 +376,7 @@ static unsigned long journal_shrink_one_cp_list(struct journal_head *jh, > jh = next_jh; > next_jh = jh->b_cpnext; > > - (*nr_to_scan)--; > - if (__cp_buffer_busy(jh)) > + if (!destroy && __cp_buffer_busy(jh)) > continue; > > nr_freed++; > @@ -429,7 +388,7 @@ static unsigned long journal_shrink_one_cp_list(struct journal_head *jh, > > if (need_resched()) > break; > - } while (jh != last_jh && *nr_to_scan); > + } while (jh != last_jh); > > return nr_freed; > } > @@ -447,11 +406,11 @@ unsigned long jbd2_journal_shrink_checkpoint_list(journal_t *journal, > unsigned long *nr_to_scan) > { > transaction_t *transaction, *last_transaction, *next_transaction; > - bool released; > + bool __maybe_unused 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; > + unsigned long freed; > > again: > spin_lock(&journal->j_list_lock); > @@ -480,10 +439,11 @@ unsigned long jbd2_journal_shrink_checkpoint_list(journal_t *journal, > 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); > + freed = journal_shrink_one_cp_list(transaction->t_checkpoint_list, > + false, &released); > + nr_freed += freed; > + (*nr_to_scan) -= min(*nr_to_scan, freed); > if (*nr_to_scan == 0) > break; > if (need_resched() || spin_needbreak(&journal->j_list_lock)) > @@ -504,9 +464,8 @@ unsigned long jbd2_journal_shrink_checkpoint_list(journal_t *journal, > 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); > + nr_freed, next_tid); > > return nr_freed; > } > @@ -522,7 +481,7 @@ unsigned long jbd2_journal_shrink_checkpoint_list(journal_t *journal, > void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy) > { > transaction_t *transaction, *last_transaction, *next_transaction; > - int ret; > + bool released; > > transaction = journal->j_checkpoint_transactions; > if (!transaction) > @@ -533,8 +492,8 @@ void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy) > do { > transaction = next_transaction; > next_transaction = transaction->t_cpnext; > - ret = journal_clean_one_cp_list(transaction->t_checkpoint_list, > - destroy); > + journal_shrink_one_cp_list(transaction->t_checkpoint_list, > + destroy, &released); > /* > * This function only frees up some memory if possible so we > * dont have an obligation to finish processing. Bail out if > @@ -547,7 +506,7 @@ void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy) > * avoids pointless scanning of transactions which still > * weren't checkpointed. > */ > - if (!ret) > + if (!released) > return; > } while (transaction != last_transaction); > } > diff --git a/include/trace/events/jbd2.h b/include/trace/events/jbd2.h > index 29414288ea3e0..34ce197bd76e0 100644 > --- a/include/trace/events/jbd2.h > +++ b/include/trace/events/jbd2.h > @@ -462,11 +462,9 @@ TRACE_EVENT(jbd2_shrink_scan_exit, > TRACE_EVENT(jbd2_shrink_checkpoint_list, > > TP_PROTO(journal_t *journal, tid_t first_tid, tid_t tid, tid_t last_tid, > - unsigned long nr_freed, unsigned long nr_scanned, > - tid_t next_tid), > + unsigned long nr_freed, tid_t next_tid), > > - TP_ARGS(journal, first_tid, tid, last_tid, nr_freed, > - nr_scanned, next_tid), > + TP_ARGS(journal, first_tid, tid, last_tid, nr_freed, next_tid), > > TP_STRUCT__entry( > __field(dev_t, dev) > @@ -474,7 +472,6 @@ TRACE_EVENT(jbd2_shrink_checkpoint_list, > __field(tid_t, tid) > __field(tid_t, last_tid) > __field(unsigned long, nr_freed) > - __field(unsigned long, nr_scanned) > __field(tid_t, next_tid) > ), > > @@ -484,15 +481,14 @@ TRACE_EVENT(jbd2_shrink_checkpoint_list, > __entry->tid = tid; > __entry->last_tid = last_tid; > __entry->nr_freed = nr_freed; > - __entry->nr_scanned = nr_scanned; > __entry->next_tid = next_tid; > ), > > TP_printk("dev %d,%d shrink transaction %u-%u(%u) freed %lu " > - "scanned %lu next transaction %u", > + "next transaction %u", > MAJOR(__entry->dev), MINOR(__entry->dev), > __entry->first_tid, __entry->tid, __entry->last_tid, > - __entry->nr_freed, __entry->nr_scanned, __entry->next_tid) > + __entry->nr_freed, __entry->next_tid) > ); > > #endif /* _TRACE_JBD2_H */ > -- > 2.39.2 > > > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
