On 5/2/18 6:45 AM, Christoph Hellwig wrote: > On Mon, Apr 30, 2018 at 09:32:50AM -0600, Jens Axboe wrote: >> We recently had a pretty severe perf regression with the XFS async >> discard. This small series add a SYNC issue discard flag, and also >> limits the chain size for sync discards. Patch 2 adds support for >> reverting XFS back to doign sync discards. > > Please explain the hardware and workload that you see this with. > Also given that it is a hardware limitation a quirk limiting the > size of discard requests and/or number of outstanding discards > would be more useful than falling back to a broken mode of issueing > block commands. Honestly, from what I've seen in production, I can whitelist one device and that one is no longer being produced. The rest is crap in terms of latency impacting trim. A quirk or whitelist/blacklist isn't going to be of any help. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
