On Wed, May 11, 2022 at 12:03:13PM +0200, Wolfgang Walter wrote:
Hi,
starting with 5.4.188 wie see a massive performance regression on our nfs-server. It basically is serving requests very very slowly with cpu utilization of 100% (with 5.4.187 and earlier it is 10%) so that it is unusable as a fileserver.
The culprit are commits (or one of it):
c32f1041382a88b17da5736886da4a492353a1bb "nfsd: cleanup nfsd_file_lru_dispose()" 628adfa21815f74c04724abc85847f24b5dd1645 "nfsd: Containerise filecache laundrette"
(upstream 36ebbdb96b694dd9c6b25ad98f2bbd263d022b63 and 9542e6a643fc69d528dfb3303f145719c61d3050)
If I revert them in v5.4.192 the kernel works as before and performance is ok again.
I did not try to revert them one by one as any disruption of our nfs-server is a severe problem for us and I'm not sure if they are related.
5.10 and 5.15 both always performed very badly on our nfs-server in a similar way so we were stuck with 5.4.
I now think this is because of 36ebbdb96b694dd9c6b25ad98f2bbd263d022b63 and/or 9542e6a643fc69d528dfb3303f145719c61d3050 though I didn't tried to revert them in 5.15 yet.
Odds are 5.18-rc6 is also a problem?
If so, I'll just wait for the fix to get into Linus's tree as this does not seem to be a stable-tree-only issue.
thanks,
greg k-h