Btrfs: Wait for async bio submissions to make some progress at queue time
Before, the btrfs bdi congestion function was used to test for too many
async bios. This keeps that check to throttle pdflush, but also
adds a check while queuing bios.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 92e14dd..bbba14b 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -429,7 +429,7 @@
return 0;
}
-static unsigned long async_submit_limit(struct btrfs_fs_info *info)
+unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
{
unsigned long limit = min_t(unsigned long,
info->workers.max_workers,
@@ -439,7 +439,8 @@
int btrfs_congested_async(struct btrfs_fs_info *info, int iodone)
{
- return atomic_read(&info->nr_async_bios) > async_submit_limit(info);
+ return atomic_read(&info->nr_async_bios) >
+ btrfs_async_submit_limit(info);
}
static void run_one_async_submit(struct btrfs_work *work)
@@ -451,12 +452,13 @@
async = container_of(work, struct async_submit_bio, work);
fs_info = BTRFS_I(async->inode)->root->fs_info;
- limit = async_submit_limit(fs_info);
+ limit = btrfs_async_submit_limit(fs_info);
limit = limit * 2 / 3;
atomic_dec(&fs_info->nr_async_submits);
- if (atomic_read(&fs_info->nr_async_submits) < limit)
+ if (atomic_read(&fs_info->nr_async_submits) < limit &&
+ waitqueue_active(&fs_info->async_submit_wait))
wake_up(&fs_info->async_submit_wait);
async->submit_bio_hook(async->inode, async->rw, async->bio,
@@ -469,7 +471,7 @@
extent_submit_bio_hook_t *submit_bio_hook)
{
struct async_submit_bio *async;
- int limit = async_submit_limit(fs_info);
+ int limit = btrfs_async_submit_limit(fs_info);
async = kmalloc(sizeof(*async), GFP_NOFS);
if (!async)
@@ -1863,10 +1865,10 @@
struct extent_io_tree *tree;
u64 num_dirty;
u64 start = 0;
- unsigned long thresh = 12 * 1024 * 1024;
+ unsigned long thresh = 96 * 1024 * 1024;
tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
- if (current_is_pdflush())
+ if (current_is_pdflush() || current->flags & PF_MEMALLOC)
return;
num_dirty = count_range_bits(tree, &start, (u64)-1,
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index e904a69..2562a27 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -73,4 +73,5 @@
int rw, struct bio *bio, int mirror_num,
extent_submit_bio_hook_t *submit_bio_hook);
int btrfs_congested_async(struct btrfs_fs_info *info, int iodone);
+unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info);
#endif
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 6bcb087..eff3ad7 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -322,8 +322,6 @@
if (ret)
break;
while(start <= end) {
- if (btrfs_congested_async(root->fs_info, 0))
- congestion_wait(WRITE, HZ/10);
cond_resched();
index = start >> PAGE_CACHE_SHIFT;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 23a5b0a..2652660 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -138,12 +138,18 @@
{
struct bio *pending;
struct backing_dev_info *bdi;
+ struct btrfs_fs_info *fs_info;
struct bio *tail;
struct bio *cur;
int again = 0;
unsigned long num_run = 0;
+ unsigned long limit;
bdi = device->bdev->bd_inode->i_mapping->backing_dev_info;
+ fs_info = device->dev_root->fs_info;
+ limit = btrfs_async_submit_limit(fs_info);
+ limit = limit * 2 / 3;
+
loop:
spin_lock(&device->io_lock);
@@ -179,7 +185,11 @@
cur = pending;
pending = pending->bi_next;
cur->bi_next = NULL;
- atomic_dec(&device->dev_root->fs_info->nr_async_bios);
+ atomic_dec(&fs_info->nr_async_bios);
+
+ if (atomic_read(&fs_info->nr_async_bios) < limit &&
+ waitqueue_active(&fs_info->async_submit_wait))
+ wake_up(&fs_info->async_submit_wait);
BUG_ON(atomic_read(&cur->bi_cnt) == 0);
bio_get(cur);
@@ -2135,6 +2145,7 @@
int rw, struct bio *bio)
{
int should_queue = 1;
+ unsigned long limit;
/* don't bother with additional async steps for reads, right now */
if (!(rw & (1 << BIO_RW))) {
@@ -2171,6 +2182,11 @@
if (should_queue)
btrfs_queue_worker(&root->fs_info->submit_workers,
&device->work);
+
+ limit = btrfs_async_submit_limit(root->fs_info);
+ wait_event_timeout(root->fs_info->async_submit_wait,
+ (atomic_read(&root->fs_info->nr_async_bios) < limit),
+ HZ/10);
return 0;
}
