On Tue, Sep 25, 2012 at 08:07:00PM +0800, Liu Bo wrote:

On 09/25/2012 07:39 PM, David Sterba wrote:

quoted

On Tue, Sep 25, 2012 at 02:48:33PM +0800, Liu Bo wrote:

quoted

--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c

@@ -1158,17 +1158,20 @@ static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
 	printk(KERN_INFO "btrfs: resize thread pool %d -> %d\n",
 	       old_pool_size, new_pool_size);
 
-	btrfs_set_max_workers(&fs_info->generic_worker, new_pool_size);
+	btrfs_set_max_workers(&fs_info->generic_worker, min(1, new_pool_size));

How could new_pool_size be < 1 ?

There's a check in super.c to pick only values > 0

I think we just need only 1 generic_worker

I got it reversed, sorry for the noise.

quoted

quoted

 	btrfs_set_max_workers(&fs_info->workers, new_pool_size);
 	btrfs_set_max_workers(&fs_info->delalloc_workers, new_pool_size);
-	btrfs_set_max_workers(&fs_info->submit_workers, new_pool_size);
-	btrfs_set_max_workers(&fs_info->caching_workers, new_pool_size);
-	btrfs_set_max_workers(&fs_info->fixup_workers, new_pool_size);
+	btrfs_set_max_workers(&fs_info->submit_workers,
+			      min_t(u64, fs_info->fs_devices->num_devices,
+			      new_pool_size));

This ask for update also when a new device is added/removed.

Oh, yes, but we should do it in another new patch instead.

Yes, this was just a hint to pair the remount/thread_pool capabilities.

david