Re: [PATCH 5.15 00/23] 5.15.160-rc1 review

[Jon Hunter]

On 29/05/2024 21:59, NeilBrown wrote:

..

> Thanks for testing.
> I can only guess that you had an active NFSv4.1 mount and that the
> callback thread was causing problems.  Please try this.  I also changed
> to use freezable_schedule* which seems like a better interface to do the
> same thing.
>
> If this doesn't fix it, we'll probably need to ask someone who remembers
> the old freezer code.
>
> Thanks,
> NeilBrown
>
>  From 518f0c1150f988b3fe8e5e0d053a25c3aa6c7d44 Mon Sep 17 00:00:00 2001
> From: NeilBrown <neilb@xxxxxxx>
> Date: Wed, 29 May 2024 09:38:22 +1000
> Subject: [PATCH] sunrpc: exclude from freezer when waiting for requests:
>
> Prior to v6.1, the freezer will only wake a kernel thread from an
> uninterruptible sleep.  Since we changed svc_get_next_xprt() to use and
> IDLE sleep the freezer cannot wake it.  we need to tell the freezer to
> ignore it instead.
>
> To make this work with only upstream requests we would need
>    Commit f5d39b020809 ("freezer,sched: Rewrite core freezer logic")
> which allows non-interruptible sleeps to be woken by the freezer.
>
> Fixes: 9b8a8e5e8129 ("nfsd: don't allow nfsd threads to be signalled.")
> Signed-off-by: NeilBrown <neilb@xxxxxxx>
> ---
>   fs/nfs/callback.c     | 2 +-
>   fs/nfsd/nfs4proc.c    | 3 ++-
>   net/sunrpc/svc_xprt.c | 4 ++--
>   3 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
> index 46a0a2d6962e..8fe143cad4a2 100644
> --- a/fs/nfs/callback.c
> +++ b/fs/nfs/callback.c
> @@ -124,7 +124,7 @@ nfs41_callback_svc(void *vrqstp)
>   		} else {
>   			spin_unlock_bh(&serv->sv_cb_lock);
>   			if (!kthread_should_stop())
> -				schedule();
> +				freezable_schedule();
>   			finish_wait(&serv->sv_cb_waitq, &wq);
>   		}
>   	}
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index 6779291efca9..e0ff2212866a 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -38,6 +38,7 @@
>   #include <linux/slab.h>
>   #include <linux/kthread.h>
>   #include <linux/namei.h>
> +#include <linux/freezer.h>
>   
>   #include <linux/sunrpc/addr.h>
>   #include <linux/nfs_ssc.h>
> @@ -1322,7 +1323,7 @@ static __be32 nfsd4_ssc_setup_dul(struct nfsd_net *nn, char *ipaddr,
>   
>   			/* allow 20secs for mount/unmount for now - revisit */
>   			if (kthread_should_stop() ||
> -					(schedule_timeout(20*HZ) == 0)) {
> +					(freezable_schedule_timeout(20*HZ) == 0)) {
>   				finish_wait(&nn->nfsd_ssc_waitq, &wait);
>   				kfree(work);
>   				return nfserr_eagain;
> diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
> index b19592673eef..3cf53e3140a5 100644
> --- a/net/sunrpc/svc_xprt.c
> +++ b/net/sunrpc/svc_xprt.c
> @@ -705,7 +705,7 @@ static int svc_alloc_arg(struct svc_rqst *rqstp)
>   			set_current_state(TASK_RUNNING);
>   			return -EINTR;
>   		}
> -		schedule_timeout(msecs_to_jiffies(500));
> +		freezable_schedule_timeout(msecs_to_jiffies(500));
>   	}
>   	rqstp->rq_page_end = &rqstp->rq_pages[pages];
>   	rqstp->rq_pages[pages] = NULL; /* this might be seen in nfsd_splice_actor() */
> @@ -765,7 +765,7 @@ static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout)
>   	smp_mb__after_atomic();
>   
>   	if (likely(rqst_should_sleep(rqstp)))
> -		time_left = schedule_timeout(timeout);
> +		time_left = freezable_schedule_timeout(timeout);
>   	else
>   		__set_current_state(TASK_RUNNING);
>   


That did the trick! Suspend is now working again on top of v5.15.160-rc1 
with this change.

Feel free to add my ...

Tested-by: Jon Hunter <jonathanh@xxxxxxxxxx>

Thanks
Jon

--
nvpublic