On Tue, Apr 04 2017, Ming Lei wrote:
> On Mon, Apr 3, 2017 at 9:18 AM, NeilBrown wrote:
>>
>> When a filesystem is mounted from a loop device, writes are
>> throttled by balance_dirty_pages() twice: once when writing
>> to the filesystem and once when the loop_handle_cmd() writes
On Tue, Apr 04 2017, Christoph Hellwig wrote:
> Looks fine,
>
> Reviewed-by: Christoph Hellwig
>
> But if you actually care about performance in any way I'd suggest
> to use the loop device in direct I/O mode..
The losetup on my test VM is too old to support that :-(
I guess it
On Mon, Apr 3, 2017 at 9:18 AM, NeilBrown wrote:
>
> When a filesystem is mounted from a loop device, writes are
> throttled by balance_dirty_pages() twice: once when writing
> to the filesystem and once when the loop_handle_cmd() writes
> to the backing file. This
On Mon 03-04-17 11:18:51, NeilBrown wrote:
>
> When a filesystem is mounted from a loop device, writes are
> throttled by balance_dirty_pages() twice: once when writing
> to the filesystem and once when the loop_handle_cmd() writes
> to the backing file. This double-throttling can trigger
>
Looks fine,
Reviewed-by: Christoph Hellwig
But if you actually care about performance in any way I'd suggest
to use the loop device in direct I/O mode..
When a filesystem is mounted from a loop device, writes are
throttled by balance_dirty_pages() twice: once when writing
to the filesystem and once when the loop_handle_cmd() writes
to the backing file. This double-throttling can trigger
positive feedback loops that create significant delays.