Re: [PATCH] btrfs: imporve delayed refs iterations

["Holger Hoffstätte" <holger@applied-asynchrony.com>]

On 10/24/16 18:46, David Sterba wrote:
> On Fri, Oct 21, 2016 at 05:05:07PM +0800, Wang Xiaoguang wrote:
>> This issue was found when I tried to delete a heavily reflinked file,
>> when deleting such files, other transaction operation will not have a
>> chance to make progress, for example, start_transaction() will blocked
>> in wait_current_trans(root) for long time, sometimes it even triggers
>> soft lockups, and the time taken to delete such heavily reflinked file
>> is also very large, often hundreds of seconds. Using perf top, it reports
>> that:
> 
>> [...] With this patch, it just took about 10~15 seconds to
>> delte the same file.
> 
> Great improvement! Patch looks good on a quick skim so I'll add it to
> next, but proper review is still required.

If it helps, I've been running it for ~2 days now with no negative side
effects, mostly rsync creating & deleting files with various levels of
reflinking (via snapshots). No problems at all.
Also tried to manually create & delete a large file with heavy CoW and
hundreds of reflinked copies - no problem either and pretty fast.

So..

Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>

cheers,
Holger