2022-02-22 04:38:22

by NeilBrown

[permalink] [raw]
Subject: [PATCH 08/11] Remove bdi_congested() and wb_congested() and related functions

These functions are no longer useful as no BDIs report congestions any
more.

Removing the test on bdi_write_contested() in current_may_throttle()
could cause a small change in behaviour, but only when PF_LOCAL_THROTTLE
is set.

So replace the calls by 'false' and simplify the code - and remove the
functions.

Acked-by: Ryusuke Konishi <[email protected]> (for nilfs bits)
Signed-off-by: NeilBrown <[email protected]>
---
drivers/block/drbd/drbd_int.h | 3 ---
drivers/block/drbd/drbd_req.c | 3 +--
fs/ext2/ialloc.c | 5 -----
fs/nilfs2/segbuf.c | 15 ---------------
fs/xfs/xfs_buf.c | 3 ---
include/linux/backing-dev.h | 26 --------------------------
mm/vmscan.c | 4 +---
7 files changed, 2 insertions(+), 57 deletions(-)

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index f27d5b0f9a0b..f804b1bfb3e6 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -638,9 +638,6 @@ enum {
STATE_SENT, /* Do not change state/UUIDs while this is set */
CALLBACK_PENDING, /* Whether we have a call_usermodehelper(, UMH_WAIT_PROC)
* pending, from drbd worker context.
- * If set, bdi_write_congested() returns true,
- * so shrink_page_list() would not recurse into,
- * and potentially deadlock on, this drbd worker.
*/
DISCONNECT_SENT,

diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 3235532ae077..2e5fb7e442e3 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -909,8 +909,7 @@ static bool remote_due_to_read_balancing(struct drbd_device *device, sector_t se

switch (rbm) {
case RB_CONGESTED_REMOTE:
- return bdi_read_congested(
- device->ldev->backing_bdev->bd_disk->bdi);
+ return 0;
case RB_LEAST_PENDING:
return atomic_read(&device->local_cnt) >
atomic_read(&device->ap_pending_cnt) + atomic_read(&device->rs_pending_cnt);
diff --git a/fs/ext2/ialloc.c b/fs/ext2/ialloc.c
index df14e750e9fe..998dd2ac8008 100644
--- a/fs/ext2/ialloc.c
+++ b/fs/ext2/ialloc.c
@@ -170,11 +170,6 @@ static void ext2_preread_inode(struct inode *inode)
unsigned long offset;
unsigned long block;
struct ext2_group_desc * gdp;
- struct backing_dev_info *bdi;
-
- bdi = inode_to_bdi(inode);
- if (bdi_rw_congested(bdi))
- return;

block_group = (inode->i_ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
gdp = ext2_get_group_desc(inode->i_sb, block_group, NULL);
diff --git a/fs/nilfs2/segbuf.c b/fs/nilfs2/segbuf.c
index 43287b0d3e9b..c4510f79037f 100644
--- a/fs/nilfs2/segbuf.c
+++ b/fs/nilfs2/segbuf.c
@@ -343,17 +343,6 @@ static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
struct bio *bio = wi->bio;
int err;

- if (segbuf->sb_nbio > 0 &&
- bdi_write_congested(segbuf->sb_super->s_bdi)) {
- wait_for_completion(&segbuf->sb_bio_event);
- segbuf->sb_nbio--;
- if (unlikely(atomic_read(&segbuf->sb_err))) {
- bio_put(bio);
- err = -EIO;
- goto failed;
- }
- }
-
bio->bi_end_io = nilfs_end_bio_write;
bio->bi_private = segbuf;
bio_set_op_attrs(bio, mode, mode_flags);
@@ -365,10 +354,6 @@ static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
wi->start = wi->end;
return 0;
-
- failed:
- wi->bio = NULL;
- return err;
}

/**
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index b45e0d50a405..b7ebcfe6b8d3 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -843,9 +843,6 @@ xfs_buf_readahead_map(
{
struct xfs_buf *bp;

- if (bdi_read_congested(target->bt_bdev->bd_disk->bdi))
- return;
-
xfs_buf_read_map(target, map, nmaps,
XBF_TRYLOCK | XBF_ASYNC | XBF_READ_AHEAD, &bp, ops,
__this_address);
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 860b675c2929..2d764566280c 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -135,11 +135,6 @@ static inline bool writeback_in_progress(struct bdi_writeback *wb)

struct backing_dev_info *inode_to_bdi(struct inode *inode);

-static inline int wb_congested(struct bdi_writeback *wb, int cong_bits)
-{
- return wb->congested & cong_bits;
-}
-
long congestion_wait(int sync, long timeout);

static inline bool mapping_can_writeback(struct address_space *mapping)
@@ -391,27 +386,6 @@ static inline void wb_blkcg_offline(struct blkcg *blkcg)

#endif /* CONFIG_CGROUP_WRITEBACK */

-static inline int bdi_congested(struct backing_dev_info *bdi, int cong_bits)
-{
- return wb_congested(&bdi->wb, cong_bits);
-}
-
-static inline int bdi_read_congested(struct backing_dev_info *bdi)
-{
- return bdi_congested(bdi, 1 << WB_sync_congested);
-}
-
-static inline int bdi_write_congested(struct backing_dev_info *bdi)
-{
- return bdi_congested(bdi, 1 << WB_async_congested);
-}
-
-static inline int bdi_rw_congested(struct backing_dev_info *bdi)
-{
- return bdi_congested(bdi, (1 << WB_sync_congested) |
- (1 << WB_async_congested));
-}
-
const char *bdi_dev_name(struct backing_dev_info *bdi);

#endif /* _LINUX_BACKING_DEV_H */
diff --git a/mm/vmscan.c b/mm/vmscan.c
index e38de6456cdc..5e1469887afa 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2364,9 +2364,7 @@ static unsigned int move_pages_to_lru(struct lruvec *lruvec,
*/
static int current_may_throttle(void)
{
- return !(current->flags & PF_LOCAL_THROTTLE) ||
- current->backing_dev_info == NULL ||
- bdi_write_congested(current->backing_dev_info);
+ return !(current->flags & PF_LOCAL_THROTTLE);
}

/*