On Thu, 2025-01-02 at 20:00 -0500, cel@xxxxxxxxxx wrote:
> From: Chuck Lever <chuck.lever@xxxxxxxxxx>
>
> Youzhong Yang <youzhong@xxxxxxxxx> noticed the workqueue subsystem
> complaining about how long the filecache laundrette was running.
> This resulted in switching from using the system_wq for the
> laundrette to system_unbound_wq (see commit 4b84551a35e3 ("nfsd: use
> system_unbound_wq for nfsd_file_gc_worker()").
>
> However, I've seen the laundrette running for multiple milliseconds
> on some workloads, delaying other work. For the purpose of
> scheduling fairness, perhaps a better choice would be to process
> filecache disposal queues on the system_long_wq instead.
>
> Cc: Tejun Heo <tj@xxxxxxxxxx>
> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> ---
> fs/nfsd/filecache.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
> index a1cdba42c4fa..91a535c2dede 100644
> --- a/fs/nfsd/filecache.c
> +++ b/fs/nfsd/filecache.c
> @@ -112,7 +112,7 @@ static void
> nfsd_file_schedule_laundrette(void)
> {
> if (test_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags))
> - queue_delayed_work(system_unbound_wq, &nfsd_filecache_laundrette,
> + queue_delayed_work(system_long_wq, &nfsd_filecache_laundrette,
> NFSD_LAUNDRETTE_DELAY);
> }
>
TIL that there is system_long_wq! Seems like a reasonable thing to do
since this is generally low-priority work.
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
