diff mbox series

[15/29] NFSD: dynamically allocate the nfsd-client shrinker

Message ID 20230622085335.77010-16-zhengqi.arch@bytedance.com (mailing list archive)
State Deferred, archived
Headers show
Series use refcount+RCU method to implement lockless slab shrink | expand

Commit Message

Qi Zheng June 22, 2023, 8:53 a.m. UTC 
In preparation for implementing lockless slab shrink,
we need to dynamically allocate the nfsd-client shrinker,
so that it can be freed asynchronously using kfree_rcu().
Then it doesn't need to wait for RCU read-side critical
section when releasing the struct nfsd_net.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
 fs/nfsd/netns.h     |  2 +-
 fs/nfsd/nfs4state.c | 20 ++++++++++++--------
 2 files changed, 13 insertions(+), 9 deletions(-)

Comments

Chuck Lever June 23, 2023, 9:49 p.m. UTC | #1 
On Thu, Jun 22, 2023 at 04:53:21PM +0800, Qi Zheng wrote:
> In preparation for implementing lockless slab shrink,
> we need to dynamically allocate the nfsd-client shrinker,
> so that it can be freed asynchronously using kfree_rcu().
> Then it doesn't need to wait for RCU read-side critical
> section when releasing the struct nfsd_net.
> 
> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>

For 15/29 and 16/29 of this series:

Acked-by: Chuck Lever <chuck.lever@oracle.com>


> ---
>  fs/nfsd/netns.h     |  2 +-
>  fs/nfsd/nfs4state.c | 20 ++++++++++++--------
>  2 files changed, 13 insertions(+), 9 deletions(-)
> 
> diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
> index ec49b200b797..f669444d5336 100644
> --- a/fs/nfsd/netns.h
> +++ b/fs/nfsd/netns.h
> @@ -195,7 +195,7 @@ struct nfsd_net {
>  	int			nfs4_max_clients;
>  
>  	atomic_t		nfsd_courtesy_clients;
> -	struct shrinker		nfsd_client_shrinker;
> +	struct shrinker		*nfsd_client_shrinker;
>  	struct work_struct	nfsd_shrinker_work;
>  };
>  
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 6e61fa3acaf1..a06184270548 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -4388,8 +4388,7 @@ static unsigned long
>  nfsd4_state_shrinker_count(struct shrinker *shrink, struct shrink_control *sc)
>  {
>  	int count;
> -	struct nfsd_net *nn = container_of(shrink,
> -			struct nfsd_net, nfsd_client_shrinker);
> +	struct nfsd_net *nn = shrink->private_data;
>  
>  	count = atomic_read(&nn->nfsd_courtesy_clients);
>  	if (!count)
> @@ -8094,14 +8093,19 @@ static int nfs4_state_create_net(struct net *net)
>  	INIT_WORK(&nn->nfsd_shrinker_work, nfsd4_state_shrinker_worker);
>  	get_net(net);
>  
> -	nn->nfsd_client_shrinker.scan_objects = nfsd4_state_shrinker_scan;
> -	nn->nfsd_client_shrinker.count_objects = nfsd4_state_shrinker_count;
> -	nn->nfsd_client_shrinker.seeks = DEFAULT_SEEKS;
> -
> -	if (register_shrinker(&nn->nfsd_client_shrinker, "nfsd-client"))
> +	nn->nfsd_client_shrinker = shrinker_alloc_and_init(nfsd4_state_shrinker_count,
> +							   nfsd4_state_shrinker_scan,
> +							   0, DEFAULT_SEEKS, 0,
> +							   nn);
> +	if (!nn->nfsd_client_shrinker)
>  		goto err_shrinker;
> +
> +	if (register_shrinker(nn->nfsd_client_shrinker, "nfsd-client"))
> +		goto err_register;
>  	return 0;
>  
> +err_register:
> +	shrinker_free(nn->nfsd_client_shrinker);
>  err_shrinker:
>  	put_net(net);
>  	kfree(nn->sessionid_hashtbl);
> @@ -8197,7 +8201,7 @@ nfs4_state_shutdown_net(struct net *net)
>  	struct list_head *pos, *next, reaplist;
>  	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
>  
> -	unregister_shrinker(&nn->nfsd_client_shrinker);
> +	unregister_and_free_shrinker(nn->nfsd_client_shrinker);
>  	cancel_work(&nn->nfsd_shrinker_work);
>  	cancel_delayed_work_sync(&nn->laundromat_work);
>  	locks_end_grace(&nn->nfsd4_manager);
> -- 
> 2.30.2
>
Qi Zheng June 24, 2023, 11:17 a.m. UTC | #2 
Hi Chuck,

On 2023/6/24 05:49, Chuck Lever wrote:
> On Thu, Jun 22, 2023 at 04:53:21PM +0800, Qi Zheng wrote:
>> In preparation for implementing lockless slab shrink,
>> we need to dynamically allocate the nfsd-client shrinker,
>> so that it can be freed asynchronously using kfree_rcu().
>> Then it doesn't need to wait for RCU read-side critical
>> section when releasing the struct nfsd_net.
>>
>> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
> 
> For 15/29 and 16/29 of this series:
> 
> Acked-by: Chuck Lever <chuck.lever@oracle.com>

Thanks for your review! :)

And I will implement the APIs suggested by Dave in 02/29 in
the v2, so there will be some changes here, but it should
not be much. So I will keep your Acked-bys in the v2.

Thanks,
Qi

> 
> 
>> ---
>>   fs/nfsd/netns.h     |  2 +-
>>   fs/nfsd/nfs4state.c | 20 ++++++++++++--------
>>   2 files changed, 13 insertions(+), 9 deletions(-)
>>
>> diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
>> index ec49b200b797..f669444d5336 100644
>> --- a/fs/nfsd/netns.h
>> +++ b/fs/nfsd/netns.h
>> @@ -195,7 +195,7 @@ struct nfsd_net {
>>   	int			nfs4_max_clients;
>>   
>>   	atomic_t		nfsd_courtesy_clients;
>> -	struct shrinker		nfsd_client_shrinker;
>> +	struct shrinker		*nfsd_client_shrinker;
>>   	struct work_struct	nfsd_shrinker_work;
>>   };
>>   
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index 6e61fa3acaf1..a06184270548 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -4388,8 +4388,7 @@ static unsigned long
>>   nfsd4_state_shrinker_count(struct shrinker *shrink, struct shrink_control *sc)
>>   {
>>   	int count;
>> -	struct nfsd_net *nn = container_of(shrink,
>> -			struct nfsd_net, nfsd_client_shrinker);
>> +	struct nfsd_net *nn = shrink->private_data;
>>   
>>   	count = atomic_read(&nn->nfsd_courtesy_clients);
>>   	if (!count)
>> @@ -8094,14 +8093,19 @@ static int nfs4_state_create_net(struct net *net)
>>   	INIT_WORK(&nn->nfsd_shrinker_work, nfsd4_state_shrinker_worker);
>>   	get_net(net);
>>   
>> -	nn->nfsd_client_shrinker.scan_objects = nfsd4_state_shrinker_scan;
>> -	nn->nfsd_client_shrinker.count_objects = nfsd4_state_shrinker_count;
>> -	nn->nfsd_client_shrinker.seeks = DEFAULT_SEEKS;
>> -
>> -	if (register_shrinker(&nn->nfsd_client_shrinker, "nfsd-client"))
>> +	nn->nfsd_client_shrinker = shrinker_alloc_and_init(nfsd4_state_shrinker_count,
>> +							   nfsd4_state_shrinker_scan,
>> +							   0, DEFAULT_SEEKS, 0,
>> +							   nn);
>> +	if (!nn->nfsd_client_shrinker)
>>   		goto err_shrinker;
>> +
>> +	if (register_shrinker(nn->nfsd_client_shrinker, "nfsd-client"))
>> +		goto err_register;
>>   	return 0;
>>   
>> +err_register:
>> +	shrinker_free(nn->nfsd_client_shrinker);
>>   err_shrinker:
>>   	put_net(net);
>>   	kfree(nn->sessionid_hashtbl);
>> @@ -8197,7 +8201,7 @@ nfs4_state_shutdown_net(struct net *net)
>>   	struct list_head *pos, *next, reaplist;
>>   	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
>>   
>> -	unregister_shrinker(&nn->nfsd_client_shrinker);
>> +	unregister_and_free_shrinker(nn->nfsd_client_shrinker);
>>   	cancel_work(&nn->nfsd_shrinker_work);
>>   	cancel_delayed_work_sync(&nn->laundromat_work);
>>   	locks_end_grace(&nn->nfsd4_manager);
>> -- 
>> 2.30.2
>>
diff mbox series

Patch

diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
index ec49b200b797..f669444d5336 100644
--- a/fs/nfsd/netns.h
+++ b/fs/nfsd/netns.h
@@ -195,7 +195,7 @@  struct nfsd_net {
 	int			nfs4_max_clients;
 
 	atomic_t		nfsd_courtesy_clients;
-	struct shrinker		nfsd_client_shrinker;
+	struct shrinker		*nfsd_client_shrinker;
 	struct work_struct	nfsd_shrinker_work;
 };
 
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 6e61fa3acaf1..a06184270548 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4388,8 +4388,7 @@  static unsigned long
 nfsd4_state_shrinker_count(struct shrinker *shrink, struct shrink_control *sc)
 {
 	int count;
-	struct nfsd_net *nn = container_of(shrink,
-			struct nfsd_net, nfsd_client_shrinker);
+	struct nfsd_net *nn = shrink->private_data;
 
 	count = atomic_read(&nn->nfsd_courtesy_clients);
 	if (!count)
@@ -8094,14 +8093,19 @@  static int nfs4_state_create_net(struct net *net)
 	INIT_WORK(&nn->nfsd_shrinker_work, nfsd4_state_shrinker_worker);
 	get_net(net);
 
-	nn->nfsd_client_shrinker.scan_objects = nfsd4_state_shrinker_scan;
-	nn->nfsd_client_shrinker.count_objects = nfsd4_state_shrinker_count;
-	nn->nfsd_client_shrinker.seeks = DEFAULT_SEEKS;
-
-	if (register_shrinker(&nn->nfsd_client_shrinker, "nfsd-client"))
+	nn->nfsd_client_shrinker = shrinker_alloc_and_init(nfsd4_state_shrinker_count,
+							   nfsd4_state_shrinker_scan,
+							   0, DEFAULT_SEEKS, 0,
+							   nn);
+	if (!nn->nfsd_client_shrinker)
 		goto err_shrinker;
+
+	if (register_shrinker(nn->nfsd_client_shrinker, "nfsd-client"))
+		goto err_register;
 	return 0;
 
+err_register:
+	shrinker_free(nn->nfsd_client_shrinker);
 err_shrinker:
 	put_net(net);
 	kfree(nn->sessionid_hashtbl);
@@ -8197,7 +8201,7 @@  nfs4_state_shutdown_net(struct net *net)
 	struct list_head *pos, *next, reaplist;
 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 
-	unregister_shrinker(&nn->nfsd_client_shrinker);
+	unregister_and_free_shrinker(nn->nfsd_client_shrinker);
 	cancel_work(&nn->nfsd_shrinker_work);
 	cancel_delayed_work_sync(&nn->laundromat_work);
 	locks_end_grace(&nn->nfsd4_manager);