Hi Chris,
I suspect the async_delalloc_pages limit checking in btrfs/inode.c
atomic_read(&root->fs_info->async_delalloc_pages) < 5 * 1042 * 1024
never evaluate to FALSE because 5M pages are 20GB which is super
large. I tried to fix it with the following patch. I increased the
limit a bit, however still worry that the "corrected" limit is too
small to create some regressions.
What do you think?
Thanks,
Fengguang
---
fs/btrfs/inode.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- linux.orig/fs/btrfs/inode.c 2009-11-07 19:28:07.000000000 +0800
+++ linux/fs/btrfs/inode.c 2009-11-07 19:28:08.000000000 +0800
@@ -50,6 +50,8 @@
#include "compression.h"
#include "locking.h"
+#define BTRFS_ASYNC_DELALLOC_PAGES_LIMIT (64 << (20-PAGE_CACHE_SHIFT))
+
struct btrfs_iget_args {
u64 ino;
struct btrfs_root *root;
@@ -856,7 +858,7 @@ static noinline void async_cow_submit(st
atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages);
if (atomic_read(&root->fs_info->async_delalloc_pages) <
- 5 * 1042 * 1024 &&
+ BTRFS_ASYNC_DELALLOC_PAGES_LIMIT / 2 &&
waitqueue_active(&root->fs_info->async_submit_wait))
wake_up(&root->fs_info->async_submit_wait);
@@ -879,7 +881,6 @@ static int cow_file_range_async(struct i
struct btrfs_root *root = BTRFS_I(inode)->root;
unsigned long nr_pages;
u64 cur_end;
- int limit = 10 * 1024 * 1042;
clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1, 0, NULL, GFP_NOFS);
@@ -910,10 +911,11 @@ static int cow_file_range_async(struct i
btrfs_queue_worker(&root->fs_info->delalloc_workers,
&async_cow->work);
- if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
+ if (atomic_read(&root->fs_info->async_delalloc_pages) >
+ BTRFS_ASYNC_DELALLOC_PAGES_LIMIT) {
wait_event(root->fs_info->async_submit_wait,
(atomic_read(&root->fs_info->async_delalloc_pages) <
- limit));
+ BTRFS_ASYNC_DELALLOC_PAGES_LIMIT));
}
while (atomic_read(&root->fs_info->async_submit_draining) &&
--
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