f2fs: introduce private bioset

In low memory scenario, we can allocate multiple bios without
submitting any of them.

- f2fs_write_checkpoint()
 - block_operations()
  - f2fs_sync_node_pages()
   step 1) flush cold nodes, allocate new bio from mempool
   - bio_alloc()
    - mempool_alloc()
   step 2) flush hot nodes, allocate a bio from mempool
   - bio_alloc()
    - mempool_alloc()
   step 3) flush warm nodes, be stuck in below call path
   - bio_alloc()
    - mempool_alloc()
     - loop to wait mempool element release, as we only
       reserved memory for two bio allocation, however above
       allocated two bios may never be submitted.

So we need avoid using default bioset, in this patch we introduce a
private bioset, in where we enlarg mempool element count to total
number of log header, so that we can make sure we have enough
backuped memory pool in scenario of allocating/holding multiple
bios.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 6 insertions, 1 deletions

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 755ad57c795b..9e85894d12c9 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3773,8 +3773,12 @@ static int __init init_f2fs_fs(void)
 	err = f2fs_init_bio_entry_cache();
 	if (err)
 		goto free_post_read;
+	err = f2fs_init_bioset();
+	if (err)
+		goto free_bio_enrty_cache;
 	return 0;
-
+free_bio_enrty_cache:
+	f2fs_destroy_bio_entry_cache();
 free_post_read:
 	f2fs_destroy_post_read_processing();
 free_root_stats:
@@ -3800,6 +3804,7 @@ fail:
 
 static void __exit exit_f2fs_fs(void)
 {
+	f2fs_destroy_bioset();
 	f2fs_destroy_bio_entry_cache();
 	f2fs_destroy_post_read_processing();
 	f2fs_destroy_root_stats();