> On Aug 17, 2020, at 6:20 PM, Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
>
> On Sun, Aug 16, 2020 at 04:46:00PM -0400, Chuck Lever wrote:
>
>> In order of application:
>>
>> 5920afa3c85f ("nfsd: hook nfsd_commit up to the nfsd_file cache")
>> 961.68user 5252.40system 20:12.30elapsed 512%CPU, 2541 DELAY errors
>> These results are similar to v5.3.
>>
>> fd4f83fd7dfb ("nfsd: convert nfs4_file->fi_fds array to use nfsd_files")
>> Does not build
>>
>> eb82dd393744 ("nfsd: convert fi_deleg_file and ls_file fields to nfsd_file")
>> 966.92user 5425.47system 33:52.79elapsed 314%CPU, 1330 DELAY errors
>>
>> Can you take a look and see if there's anything obvious?
>
> Unfortunately nothing about the file cache code is very obvious to me.
> I'm looking at it....
>
> It adds some new nfserr_jukebox returns in nfsd_file_acquire. Those
> mostly look like kmalloc failures, the one I'm not sure about is the
> NFSD_FILE_HASHED check.
>
> Or maybe it's the lease break there.
nfsd_file_acquire() always calls fh_verify() before it invokes nfsd_open().
Replacing nfs4_get_vfs_file's nfsd_open() call with nfsd_file_acquire() adds
almost 10 million fh_verify() calls to my test run.
On my server, fh_verify() is quite expensive. Most of the cost is in the
prepare_creds() call.
--
Chuck Lever
