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linux/include/uapi/linux/eventpoll.h

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License cleanup: add SPDX license identifier to uapi header files with a license Many user space API headers have licensing information, which is either incomplete, badly formatted or just a shorthand for referring to the license under which the file is supposed to be. This makes it hard for compliance tools to determine the correct license. Update these files with an SPDX license identifier. The identifier was chosen based on the license information in the file. GPL/LGPL licensed headers get the matching GPL/LGPL SPDX license identifier with the added 'WITH Linux-syscall-note' exception, which is the officially assigned exception identifier for the kernel syscall exception: NOTE! This copyright does *not* cover user programs that use kernel services by normal system calls - this is merely considered normal use of the kernel, and does *not* fall under the heading of "derived work". This exception makes it possible to include GPL headers into non GPL code, without confusing license compliance tools. Headers which have either explicit dual licensing or are just licensed under a non GPL license are updated with the corresponding SPDX identifier and the GPLv2 with syscall exception identifier. The format is: ((GPL-2.0 WITH Linux-syscall-note) OR SPDX-ID-OF-OTHER-LICENSE) SPDX license identifiers are a legally binding shorthand, which can be used instead of the full boiler plate text. The update does not remove existing license information as this has to be done on a case by case basis and the copyright holders might have to be consulted. This will happen in a separate step. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. See the previous patch in this series for the methodology of how this patch was researched. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 15:09:13 +01:00
UAPI: (Scripted) Disintegrate include/linux Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com>
2012-10-13 10:46:48 +01:00
eventpoll.h: add missing epoll event masks [resend due to me forgetting to cc: linux-api the first time around I posted these back on Feb 23] From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> For some reason these values are not in the uapi header file, so any libc has to define it themselves. To prevent them from needing to do this, just have the kernel provide the correct values. Reported-by: Elliott Hughes <enh@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-08 19:03:44 +01:00
add EPOLLNVAL, annotate EPOLL... and event_poll->event Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-02-01 11:00:50 -05:00
eventpoll.h: add missing epoll event masks [resend due to me forgetting to cc: linux-api the first time around I posted these back on Feb 23] From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> For some reason these values are not in the uapi header file, so any libc has to define it themselves. To prevent them from needing to do this, just have the kernel provide the correct values. Reported-by: Elliott Hughes <enh@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-08 19:03:44 +01:00
eventpoll: add EPOLL_URING_WAKE poll wakeup flag We can have dependencies between epoll and io_uring. Consider an epoll context, identified by the epfd file descriptor, and an io_uring file descriptor identified by iofd. If we add iofd to the epfd context, and arm a multishot poll request for epfd with iofd, then the multishot poll request will repeatedly trigger and generate events until terminated by CQ ring overflow. This isn't a desired behavior. Add EPOLL_URING so that io_uring can pass it in as part of the poll wakeup key, and io_uring can check for that to detect a potential recursive invocation. Cc: stable@vger.kernel.org # 6.0 Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-20 10:10:53 -07:00
epoll: add EPOLLEXCLUSIVE flag Currently, epoll file descriptors or epfds (the fd returned from epoll_create[1]()) that are added to a shared wakeup source are always added in a non-exclusive manner. This means that when we have multiple epfds attached to a shared fd source they are all woken up. This creates thundering herd type behavior. Introduce a new 'EPOLLEXCLUSIVE' flag that can be passed as part of the 'event' argument during an epoll_ctl() EPOLL_CTL_ADD operation. This new flag allows for exclusive wakeups when there are multiple epfds attached to a shared fd event source. The implementation walks the list of exclusive waiters, and queues an event to each epfd, until it finds the first waiter that has threads blocked on it via epoll_wait(). The idea is to search for threads which are idle and ready to process the wakeup events. Thus, we queue an event to at least 1 epfd, but may still potentially queue an event to all epfds that are attached to the shared fd source. Performance testing was done by Madars Vitolins using a modified version of Enduro/X. The use of the 'EPOLLEXCLUSIVE' flag reduce the length of this particular workload from 860s down to 24s. Sample epoll_clt text: EPOLLEXCLUSIVE Sets an exclusive wakeup mode for the epfd file descriptor that is being attached to the target file descriptor, fd. Thus, when an event occurs and multiple epfd file descriptors are attached to the same target file using EPOLLEXCLUSIVE, one or more epfds will receive an event with epoll_wait(2). The default in this scenario (when EPOLLEXCLUSIVE is not set) is for all epfds to receive an event. EPOLLEXCLUSIVE may only be specified with the op EPOLL_CTL_ADD. Signed-off-by: Jason Baron <jbaron@akamai.com> Tested-by: Madars Vitolins <m@silodev.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Eric Wong <normalperson@yhbt.net> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hagen Paul Pfeifer <hagen@jauu.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-20 14:59:24 -08:00
eventpoll.h: wrap casts in () properly When importing the latest copy of the kernel headers into Bionic, Christpher and Elliott noticed that the eventpoll.h casts were not wrapped in (). As it is, clang complains about macros without surrounding (), so this makes it a pain for userspace tools. So fix it up by adding another () pair, and make them line up purty by using tabs. Fixes: 65aaf87b3aa2 ("add EPOLLNVAL, annotate EPOLL... and event_poll->event") Reported-by: Christopher Ferris <cferris@google.com> Reported-by: Elliott Hughes <enh@google.com> Cc: stable <stable@vger.kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-10 17:15:38 +02:00
epoll: add EPOLLEXCLUSIVE flag Currently, epoll file descriptors or epfds (the fd returned from epoll_create[1]()) that are added to a shared wakeup source are always added in a non-exclusive manner. This means that when we have multiple epfds attached to a shared fd source they are all woken up. This creates thundering herd type behavior. Introduce a new 'EPOLLEXCLUSIVE' flag that can be passed as part of the 'event' argument during an epoll_ctl() EPOLL_CTL_ADD operation. This new flag allows for exclusive wakeups when there are multiple epfds attached to a shared fd event source. The implementation walks the list of exclusive waiters, and queues an event to each epfd, until it finds the first waiter that has threads blocked on it via epoll_wait(). The idea is to search for threads which are idle and ready to process the wakeup events. Thus, we queue an event to at least 1 epfd, but may still potentially queue an event to all epfds that are attached to the shared fd source. Performance testing was done by Madars Vitolins using a modified version of Enduro/X. The use of the 'EPOLLEXCLUSIVE' flag reduce the length of this particular workload from 860s down to 24s. Sample epoll_clt text: EPOLLEXCLUSIVE Sets an exclusive wakeup mode for the epfd file descriptor that is being attached to the target file descriptor, fd. Thus, when an event occurs and multiple epfd file descriptors are attached to the same target file using EPOLLEXCLUSIVE, one or more epfds will receive an event with epoll_wait(2). The default in this scenario (when EPOLLEXCLUSIVE is not set) is for all epfds to receive an event. EPOLLEXCLUSIVE may only be specified with the op EPOLL_CTL_ADD. Signed-off-by: Jason Baron <jbaron@akamai.com> Tested-by: Madars Vitolins <m@silodev.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Eric Wong <normalperson@yhbt.net> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hagen Paul Pfeifer <hagen@jauu.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-20 14:59:24 -08:00
UAPI: (Scripted) Disintegrate include/linux Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com>
2012-10-13 10:46:48 +01:00
eventpoll.h: wrap casts in () properly When importing the latest copy of the kernel headers into Bionic, Christpher and Elliott noticed that the eventpoll.h casts were not wrapped in (). As it is, clang complains about macros without surrounding (), so this makes it a pain for userspace tools. So fix it up by adding another () pair, and make them line up purty by using tabs. Fixes: 65aaf87b3aa2 ("add EPOLLNVAL, annotate EPOLL... and event_poll->event") Reported-by: Christopher Ferris <cferris@google.com> Reported-by: Elliott Hughes <enh@google.com> Cc: stable <stable@vger.kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-10 17:15:38 +02:00
UAPI: (Scripted) Disintegrate include/linux Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com>
2012-10-13 10:46:48 +01:00
eventpoll.h: wrap casts in () properly When importing the latest copy of the kernel headers into Bionic, Christpher and Elliott noticed that the eventpoll.h casts were not wrapped in (). As it is, clang complains about macros without surrounding (), so this makes it a pain for userspace tools. So fix it up by adding another () pair, and make them line up purty by using tabs. Fixes: 65aaf87b3aa2 ("add EPOLLNVAL, annotate EPOLL... and event_poll->event") Reported-by: Christopher Ferris <cferris@google.com> Reported-by: Elliott Hughes <enh@google.com> Cc: stable <stable@vger.kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-10 17:15:38 +02:00
UAPI: (Scripted) Disintegrate include/linux Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com>
2012-10-13 10:46:48 +01:00
eventpoll.h: wrap casts in () properly When importing the latest copy of the kernel headers into Bionic, Christpher and Elliott noticed that the eventpoll.h casts were not wrapped in (). As it is, clang complains about macros without surrounding (), so this makes it a pain for userspace tools. So fix it up by adding another () pair, and make them line up purty by using tabs. Fixes: 65aaf87b3aa2 ("add EPOLLNVAL, annotate EPOLL... and event_poll->event") Reported-by: Christopher Ferris <cferris@google.com> Reported-by: Elliott Hughes <enh@google.com> Cc: stable <stable@vger.kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-10 17:15:38 +02:00
UAPI: (Scripted) Disintegrate include/linux Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com>
2012-10-13 10:46:48 +01:00
add EPOLLNVAL, annotate EPOLL... and event_poll->event Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-02-01 11:00:50 -05:00
UAPI: (Scripted) Disintegrate include/linux Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com>
2012-10-13 10:46:48 +01:00
eventpoll: Add epoll ioctl for epoll_params Add an ioctl for getting and setting epoll_params. User programs can use this ioctl to get and set the busy poll usec time, packet budget, and prefer busy poll params for a specific epoll context. Parameters are limited: - busy_poll_usecs is limited to <= s32_max - busy_poll_budget is limited to <= NAPI_POLL_WEIGHT by unprivileged users (!capable(CAP_NET_ADMIN)) - prefer_busy_poll must be 0 or 1 - __pad must be 0 Signed-off-by: Joe Damato <jdamato@fastly.com> Acked-by: Stanislav Fomichev <sdf@google.com> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-02-13 06:16:45 +00:00
UAPI: (Scripted) Disintegrate include/linux Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com>
2012-10-13 10:46:48 +01:00