From: Joe Damato <jdamato@fastly.com>
To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: chuck.lever@oracle.com, jlayton@kernel.org,
linux-api@vger.kernel.org, brauner@kernel.org,
edumazet@google.com, davem@davemloft.net,
alexander.duyck@gmail.com, sridhar.samudrala@intel.com,
kuba@kernel.org, Joe Damato <jdamato@fastly.com>
Subject: [net-next 1/3] eventpoll: support busy poll per epoll instance
Date: Wed, 24 Jan 2024 02:53:57 +0000 [thread overview]
Message-ID: <20240124025359.11419-2-jdamato@fastly.com> (raw)
In-Reply-To: <20240124025359.11419-1-jdamato@fastly.com>
Allow busy polling on a per-epoll context basis. The per-epoll context
usec timeout value is preferred, but the pre-existing system wide sysctl
value is still supported if it specified.
Signed-off-by: Joe Damato <jdamato@fastly.com>
---
fs/eventpoll.c | 49 +++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 45 insertions(+), 4 deletions(-)
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 3534d36a1474..4503fec01278 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -227,6 +227,8 @@ struct eventpoll {
#ifdef CONFIG_NET_RX_BUSY_POLL
/* used to track busy poll napi_id */
unsigned int napi_id;
+ /* busy poll timeout */
+ u64 busy_poll_usecs;
#endif
#ifdef CONFIG_DEBUG_LOCK_ALLOC
@@ -386,12 +388,44 @@ static inline int ep_events_available(struct eventpoll *ep)
READ_ONCE(ep->ovflist) != EP_UNACTIVE_PTR;
}
+/**
+ * busy_loop_ep_timeout - check if busy poll has timed out. The timeout value
+ * from the epoll instance ep is preferred, but if it is not set fallback to
+ * the system-wide global via busy_loop_timeout.
+ *
+ * @start_time: The start time used to compute the remaining time until timeout.
+ * @ep: Pointer to the eventpoll context.
+ *
+ * Return: true if the timeout has expired, false otherwise.
+ */
+static inline bool busy_loop_ep_timeout(unsigned long start_time, struct eventpoll *ep)
+{
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ unsigned long bp_usec = READ_ONCE(ep->busy_poll_usecs);
+
+ if (bp_usec) {
+ unsigned long end_time = start_time + bp_usec;
+ unsigned long now = busy_loop_current_time();
+
+ return time_after(now, end_time);
+ } else {
+ return busy_loop_timeout(start_time);
+ }
+#endif
+ return true;
+}
+
#ifdef CONFIG_NET_RX_BUSY_POLL
+static bool ep_busy_loop_on(struct eventpoll *ep)
+{
+ return !!ep->busy_poll_usecs ^ net_busy_loop_on();
+}
+
static bool ep_busy_loop_end(void *p, unsigned long start_time)
{
struct eventpoll *ep = p;
- return ep_events_available(ep) || busy_loop_timeout(start_time);
+ return ep_events_available(ep) || busy_loop_ep_timeout(start_time, ep);
}
/*
@@ -404,7 +438,7 @@ static bool ep_busy_loop(struct eventpoll *ep, int nonblock)
{
unsigned int napi_id = READ_ONCE(ep->napi_id);
- if ((napi_id >= MIN_NAPI_ID) && net_busy_loop_on()) {
+ if ((napi_id >= MIN_NAPI_ID) && ep_busy_loop_on(ep)) {
napi_busy_loop(napi_id, nonblock ? NULL : ep_busy_loop_end, ep, false,
BUSY_POLL_BUDGET);
if (ep_events_available(ep))
@@ -430,7 +464,8 @@ static inline void ep_set_busy_poll_napi_id(struct epitem *epi)
struct socket *sock;
struct sock *sk;
- if (!net_busy_loop_on())
+ ep = epi->ep;
+ if (!ep_busy_loop_on(ep))
return;
sock = sock_from_file(epi->ffd.file);
@@ -442,7 +477,6 @@ static inline void ep_set_busy_poll_napi_id(struct epitem *epi)
return;
napi_id = READ_ONCE(sk->sk_napi_id);
- ep = epi->ep;
/* Non-NAPI IDs can be rejected
* or
@@ -466,6 +500,10 @@ static inline void ep_set_busy_poll_napi_id(struct epitem *epi)
{
}
+static inline bool ep_busy_loop_on(struct eventpoll *ep)
+{
+ return false;
+}
#endif /* CONFIG_NET_RX_BUSY_POLL */
/*
@@ -2058,6 +2096,9 @@ static int do_epoll_create(int flags)
error = PTR_ERR(file);
goto out_free_fd;
}
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ ep->busy_poll_usecs = 0;
+#endif
ep->file = file;
fd_install(fd, file);
return fd;
--
2.25.1
next prev parent reply other threads:[~2024-01-24 2:54 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-24 2:53 [net-next 0/3] Per epoll context busy poll support Joe Damato
2024-01-24 2:53 ` Joe Damato [this message]
2024-01-24 2:53 ` [net-next 2/3] eventpoll: Add per-epoll busy poll packet budget Joe Damato
2024-01-24 2:53 ` [net-next 3/3] eventpoll: Add epoll ioctl for epoll_params Joe Damato
2024-01-24 15:37 ` Joe Damato
2024-01-24 8:20 ` [net-next 0/3] Per epoll context busy poll support Eric Dumazet
2024-01-24 14:20 ` Joe Damato
2024-01-24 14:38 ` Eric Dumazet
2024-01-24 15:19 ` Joe Damato
2024-01-30 18:54 ` Samudrala, Sridhar
2024-02-02 3:28 ` Joe Damato
2024-02-02 17:23 ` Samudrala, Sridhar
2024-02-02 18:22 ` Jakub Kicinski
2024-02-02 19:33 ` Joe Damato
2024-02-02 19:58 ` Jakub Kicinski
2024-02-02 20:23 ` Joe Damato
2024-02-02 20:50 ` Samudrala, Sridhar
2024-02-02 20:55 ` Joe Damato
2024-02-03 1:15 ` Jakub Kicinski
2024-02-05 18:17 ` Stanislav Fomichev
2024-02-05 18:52 ` Joe Damato
2024-02-05 19:48 ` Jakub Kicinski
2024-02-05 18:51 ` Joe Damato
2024-02-05 19:59 ` Jakub Kicinski
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