5.15-stable review patch. If anyone has any objections, please let me know.
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From: Chuck Lever chuck.lever@oracle.com
[ Upstream commit a9ff2e99e9fa501ec965da03c18a5422b37a2f44 ]
We have never been able to track down and address the underlying cause of the performance issues with workqueue-based service support. svo_enqueue_xprt is called multiple times per RPC, so it adds instruction path length, but always ends up at the same function: svc_xprt_do_enqueue(). We do not anticipate needing this flexibility for dynamic nfsd thread management support.
As a micro-optimization, remove .svo_enqueue_xprt because Spectre/Meltdown makes virtual function calls more costly.
This change essentially reverts commit b9e13cdfac70 ("nfsd/sunrpc: turn enqueueing a svc_xprt into a svc_serv operation").
Signed-off-by: Chuck Lever chuck.lever@oracle.com --- fs/lockd/svc.c | 1 - fs/nfs/callback.c | 2 -- fs/nfsd/nfssvc.c | 1 - include/linux/sunrpc/svc.h | 3 --- include/linux/sunrpc/svc_xprt.h | 1 - net/sunrpc/svc_xprt.c | 10 +++++----- 6 files changed, 5 insertions(+), 13 deletions(-)
diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c index 0475c5a5d061e..3a05af8736259 100644 --- a/fs/lockd/svc.c +++ b/fs/lockd/svc.c @@ -353,7 +353,6 @@ static struct notifier_block lockd_inet6addr_notifier = { static const struct svc_serv_ops lockd_sv_ops = { .svo_shutdown = svc_rpcb_cleanup, .svo_function = lockd, - .svo_enqueue_xprt = svc_xprt_do_enqueue, .svo_module = THIS_MODULE, };
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c index 054cc1255fac6..7a810f8850632 100644 --- a/fs/nfs/callback.c +++ b/fs/nfs/callback.c @@ -234,13 +234,11 @@ static int nfs_callback_up_net(int minorversion, struct svc_serv *serv,
static const struct svc_serv_ops nfs40_cb_sv_ops = { .svo_function = nfs4_callback_svc, - .svo_enqueue_xprt = svc_xprt_do_enqueue, .svo_module = THIS_MODULE, }; #if defined(CONFIG_NFS_V4_1) static const struct svc_serv_ops nfs41_cb_sv_ops = { .svo_function = nfs41_callback_svc, - .svo_enqueue_xprt = svc_xprt_do_enqueue, .svo_module = THIS_MODULE, };
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c index 2efe9d33a2827..3b79b97f2715d 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -615,7 +615,6 @@ static int nfsd_get_default_max_blksize(void) static const struct svc_serv_ops nfsd_thread_sv_ops = { .svo_shutdown = nfsd_last_thread, .svo_function = nfsd, - .svo_enqueue_xprt = svc_xprt_do_enqueue, .svo_module = THIS_MODULE, };
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h index be535cc4fea07..2c1a80ec7c3dc 100644 --- a/include/linux/sunrpc/svc.h +++ b/include/linux/sunrpc/svc.h @@ -61,9 +61,6 @@ struct svc_serv_ops { /* function for service threads to run */ int (*svo_function)(void *);
- /* queue up a transport for servicing */ - void (*svo_enqueue_xprt)(struct svc_xprt *); - /* optional module to count when adding threads. * Thread function must call module_put_and_kthread_exit() to exit. */ diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h index 154eee6bc6a01..05a3ccd837f57 100644 --- a/include/linux/sunrpc/svc_xprt.h +++ b/include/linux/sunrpc/svc_xprt.h @@ -131,7 +131,6 @@ int svc_create_xprt(struct svc_serv *, const char *, struct net *, const int, const unsigned short, int, const struct cred *); void svc_xprt_received(struct svc_xprt *xprt); -void svc_xprt_do_enqueue(struct svc_xprt *xprt); void svc_xprt_enqueue(struct svc_xprt *xprt); void svc_xprt_put(struct svc_xprt *xprt); void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt); diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index 5ff8f902f14d2..795dc8eb2e1d5 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -31,6 +31,7 @@ static int svc_deferred_recv(struct svc_rqst *rqstp); static struct cache_deferred_req *svc_defer(struct cache_req *req); static void svc_age_temp_xprts(struct timer_list *t); static void svc_delete_xprt(struct svc_xprt *xprt); +static void svc_xprt_do_enqueue(struct svc_xprt *xprt);
/* apparently the "standard" is that clients close * idle connections after 5 minutes, servers after @@ -267,12 +268,12 @@ void svc_xprt_received(struct svc_xprt *xprt) trace_svc_xprt_received(xprt);
/* As soon as we clear busy, the xprt could be closed and - * 'put', so we need a reference to call svc_enqueue_xprt with: + * 'put', so we need a reference to call svc_xprt_do_enqueue with: */ svc_xprt_get(xprt); smp_mb__before_atomic(); clear_bit(XPT_BUSY, &xprt->xpt_flags); - xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt); + svc_xprt_do_enqueue(xprt); svc_xprt_put(xprt); } EXPORT_SYMBOL_GPL(svc_xprt_received); @@ -424,7 +425,7 @@ static bool svc_xprt_ready(struct svc_xprt *xprt) return false; }
-void svc_xprt_do_enqueue(struct svc_xprt *xprt) +static void svc_xprt_do_enqueue(struct svc_xprt *xprt) { struct svc_pool *pool; struct svc_rqst *rqstp = NULL; @@ -468,7 +469,6 @@ void svc_xprt_do_enqueue(struct svc_xprt *xprt) put_cpu(); trace_svc_xprt_do_enqueue(xprt, rqstp); } -EXPORT_SYMBOL_GPL(svc_xprt_do_enqueue);
/* * Queue up a transport with data pending. If there are idle nfsd @@ -479,7 +479,7 @@ void svc_xprt_enqueue(struct svc_xprt *xprt) { if (test_bit(XPT_BUSY, &xprt->xpt_flags)) return; - xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt); + svc_xprt_do_enqueue(xprt); } EXPORT_SYMBOL_GPL(svc_xprt_enqueue);