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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 --- 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 =20 #ifdef CONFIG_DEBUG_LOCK_ALLOC @@ -386,12 +388,44 @@ static inline int ep_events_available(struct eventpol= l *ep) READ_ONCE(ep->ovflist) !=3D EP_UNACTIVE_PTR; } =20 +/** + * busy_loop_ep_timeout - check if busy poll has timed out. The timeout va= lue + * 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 ti= meout. + * @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 e= ventpoll *ep) +{ +#ifdef CONFIG_NET_RX_BUSY_POLL + unsigned long bp_usec =3D READ_ONCE(ep->busy_poll_usecs); + + if (bp_usec) { + unsigned long end_time =3D start_time + bp_usec; + unsigned long now =3D 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 =3D p; =20 - return ep_events_available(ep) || busy_loop_timeout(start_time); + return ep_events_available(ep) || busy_loop_ep_timeout(start_time, ep); } =20 /* @@ -404,7 +438,7 @@ static bool ep_busy_loop(struct eventpoll *ep, int nonb= lock) { unsigned int napi_id =3D READ_ONCE(ep->napi_id); =20 - if ((napi_id >=3D MIN_NAPI_ID) && net_busy_loop_on()) { + if ((napi_id >=3D 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 epit= em *epi) struct socket *sock; struct sock *sk; =20 - if (!net_busy_loop_on()) + ep =3D epi->ep; + if (!ep_busy_loop_on(ep)) return; =20 sock =3D sock_from_file(epi->ffd.file); @@ -442,7 +477,6 @@ static inline void ep_set_busy_poll_napi_id(struct epit= em *epi) return; =20 napi_id =3D READ_ONCE(sk->sk_napi_id); - ep =3D epi->ep; =20 /* Non-NAPI IDs can be rejected * or @@ -466,6 +500,10 @@ static inline void ep_set_busy_poll_napi_id(struct epi= tem *epi) { } =20 +static inline bool ep_busy_loop_on(struct eventpoll *ep) +{ + return false; +} #endif /* CONFIG_NET_RX_BUSY_POLL */ =20 /* @@ -2058,6 +2096,9 @@ static int do_epoll_create(int flags) error =3D PTR_ERR(file); goto out_free_fd; } +#ifdef CONFIG_NET_RX_BUSY_POLL + ep->busy_poll_usecs =3D 0; +#endif ep->file =3D file; fd_install(fd, file); return fd; --=20 2.25.1 From nobody Wed Dec 24 19:49:19 2025 Received: from mail-pf1-f180.google.com (mail-pf1-f180.google.com [209.85.210.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3ED9917545 for ; 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charset="utf-8" When using epoll-based busy poll, the packet budget is hardcoded to BUSY_POLL_BUDGET (8). Add support for a per-epoll context busy poll packet budget. If not specified, the default value (BUSY_POLL_BUDGET) is used. Signed-off-by: Joe Damato --- fs/eventpoll.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 4503fec01278..40bd97477b91 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -229,6 +229,8 @@ struct eventpoll { unsigned int napi_id; /* busy poll timeout */ u64 busy_poll_usecs; + /* busy poll packet budget */ + u16 busy_poll_budget; #endif =20 #ifdef CONFIG_DEBUG_LOCK_ALLOC @@ -437,10 +439,14 @@ static bool ep_busy_loop_end(void *p, unsigned long s= tart_time) static bool ep_busy_loop(struct eventpoll *ep, int nonblock) { unsigned int napi_id =3D READ_ONCE(ep->napi_id); + u16 budget =3D READ_ONCE(ep->busy_poll_budget); + + if (!budget) + budget =3D BUSY_POLL_BUDGET; =20 if ((napi_id >=3D MIN_NAPI_ID) && ep_busy_loop_on(ep)) { napi_busy_loop(napi_id, nonblock ? 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User programs can use this ioctl to get and set the busy poll usec time or packet budget params for a specific epoll context. Signed-off-by: Joe Damato --- .../userspace-api/ioctl/ioctl-number.rst | 1 + fs/eventpoll.c | 41 +++++++++++++++++++ include/uapi/linux/eventpoll.h | 12 ++++++ 3 files changed, 54 insertions(+) diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documenta= tion/userspace-api/ioctl/ioctl-number.rst index 457e16f06e04..b33918232f78 100644 --- a/Documentation/userspace-api/ioctl/ioctl-number.rst +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst @@ -309,6 +309,7 @@ Code Seq# Include File = Comments 0x89 0B-DF linux/sockios.h 0x89 E0-EF linux/sockios.h SIOCP= ROTOPRIVATE range 0x89 F0-FF linux/sockios.h SIOCD= EVPRIVATE range +0x8A 00-1F linux/eventpoll.h 0x8B all linux/wireless.h 0x8C 00-3F WiNRA= DiO driver diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 40bd97477b91..d973147c015c 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -869,6 +869,45 @@ static void ep_clear_and_put(struct eventpoll *ep) ep_free(ep); } =20 +static long ep_eventpoll_ioctl(struct file *file, unsigned int cmd, unsign= ed long arg) +{ + int ret; + struct eventpoll *ep; + struct epoll_params epoll_params; + void __user *uarg =3D (void __user *) arg; + + if (!is_file_epoll(file)) + return -EINVAL; + + ep =3D file->private_data; + + switch (cmd) { +#ifdef CONFIG_NET_RX_BUSY_POLL + case EPIOCSPARAMS: + if (copy_from_user(&epoll_params, uarg, sizeof(epoll_params))) + return -EFAULT; + + ep->busy_poll_usecs =3D epoll_params.busy_poll_usecs; + ep->busy_poll_budget =3D epoll_params.busy_poll_budget; + return 0; + + case EPIOCGPARAMS: + memset(&epoll_params, 0, sizeof(epoll_params)); + epoll_params.busy_poll_usecs =3D ep->busy_poll_usecs; + epoll_params.busy_poll_budget =3D ep->busy_poll_budget; + if (copy_to_user(uarg, &epoll_params, sizeof(epoll_params))) + return -EFAULT; + + return 0; +#endif + default: + ret =3D -EINVAL; + break; + } + + return ret; +} + static int ep_eventpoll_release(struct inode *inode, struct file *file) { struct eventpoll *ep =3D file->private_data; @@ -975,6 +1014,8 @@ static const struct file_operations eventpoll_fops =3D= { .release =3D ep_eventpoll_release, .poll =3D ep_eventpoll_poll, .llseek =3D noop_llseek, + .unlocked_ioctl =3D ep_eventpoll_ioctl, + .compat_ioctl =3D compat_ptr_ioctl, }; =20 /* diff --git a/include/uapi/linux/eventpoll.h b/include/uapi/linux/eventpoll.h index cfbcc4cc49ac..9211103779c4 100644 --- a/include/uapi/linux/eventpoll.h +++ b/include/uapi/linux/eventpoll.h @@ -85,4 +85,16 @@ struct epoll_event { __u64 data; } EPOLL_PACKED; =20 +struct epoll_params { + u64 busy_poll_usecs; + u16 busy_poll_budget; + + /* for future fields */ + uint8_t data[118]; +} EPOLL_PACKED; + +#define EPOLL_IOC_TYPE 0x8A +#define EPIOCSPARAMS _IOW(EPOLL_IOC_TYPE, 0x01, struct epoll_params) +#define EPIOCGPARAMS _IOR(EPOLL_IOC_TYPE, 0x02, struct epoll_params) + #endif /* _UAPI_LINUX_EVENTPOLL_H */ --=20 2.25.1