5.15-stable review patch. If anyone has any objections, please let me know.
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From: Zhang Yi yi.zhang@huawei.com
commit 373ac521799d9e97061515aca6ec6621789036bb upstream.
journal_clean_one_cp_list() has been merged into journal_shrink_one_cp_list(), but do chekpoint buffer cleanup from the committing process is just a best effort, it should stop scan once it meet a busy buffer, or else it will cause a lot of invalid buffer scan and checks. We catch a performance regression when doing fs_mark tests below.
Test cmd: ./fs_mark -d scratch -s 1024 -n 10000 -t 1 -D 100 -N 100
Before merging checkpoint buffer cleanup: FSUse% Count Size Files/sec App Overhead 95 10000 1024 8304.9 49033
After merging checkpoint buffer cleanup: FSUse% Count Size Files/sec App Overhead 95 10000 1024 7649.0 50012 FSUse% Count Size Files/sec App Overhead 95 10000 1024 2107.1 50871
After merging checkpoint buffer cleanup, the total loop count in journal_shrink_one_cp_list() could be up to 6,261,600+ (50,000+ ~ 100,000+ in general), most of them are invalid. This patch fix it through passing 'shrink_type' into journal_shrink_one_cp_list() and add a new 'SHRINK_BUSY_STOP' to indicate it should stop once meet a busy buffer. After fix, the loop count descending back to 10,000+.
After this fix: FSUse% Count Size Files/sec App Overhead 95 10000 1024 8558.4 49109
Cc: stable@kernel.org Fixes: b98dba273a0e ("jbd2: remove journal_clean_one_cp_list()") Signed-off-by: Zhang Yi yi.zhang@huawei.com Reviewed-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/r/20230714025528.564988-2-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/jbd2/checkpoint.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-)
--- a/fs/jbd2/checkpoint.c +++ b/fs/jbd2/checkpoint.c @@ -349,6 +349,8 @@ int jbd2_cleanup_journal_tail(journal_t
/* Checkpoint list management */
+enum shrink_type {SHRINK_DESTROY, SHRINK_BUSY_STOP, SHRINK_BUSY_SKIP}; + /* * journal_shrink_one_cp_list * @@ -360,7 +362,8 @@ int jbd2_cleanup_journal_tail(journal_t * Called with j_list_lock held. */ static unsigned long journal_shrink_one_cp_list(struct journal_head *jh, - bool destroy, bool *released) + enum shrink_type type, + bool *released) { struct journal_head *last_jh; struct journal_head *next_jh = jh; @@ -376,12 +379,15 @@ static unsigned long journal_shrink_one_ jh = next_jh; next_jh = jh->b_cpnext;
- if (destroy) { + if (type == SHRINK_DESTROY) { ret = __jbd2_journal_remove_checkpoint(jh); } else { ret = jbd2_journal_try_remove_checkpoint(jh); - if (ret < 0) - continue; + if (ret < 0) { + if (type == SHRINK_BUSY_SKIP) + continue; + break; + } }
nr_freed++; @@ -445,7 +451,7 @@ again: tid = transaction->t_tid;
freed = journal_shrink_one_cp_list(transaction->t_checkpoint_list, - false, &released); + SHRINK_BUSY_SKIP, &released); nr_freed += freed; (*nr_to_scan) -= min(*nr_to_scan, freed); if (*nr_to_scan == 0) @@ -485,19 +491,21 @@ out: void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy) { transaction_t *transaction, *last_transaction, *next_transaction; + enum shrink_type type; bool released;
transaction = journal->j_checkpoint_transactions; if (!transaction) return;
+ type = destroy ? SHRINK_DESTROY : SHRINK_BUSY_STOP; last_transaction = transaction->t_cpprev; next_transaction = transaction; do { transaction = next_transaction; next_transaction = transaction->t_cpnext; journal_shrink_one_cp_list(transaction->t_checkpoint_list, - destroy, &released); + type, &released); /* * This function only frees up some memory if possible so we * dont have an obligation to finish processing. Bail out if