linux_dsm_epyc7002/include/uapi/linux/sched.h

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License cleanup: add SPDX license identifier to uapi header files with no license Many user space API headers are missing licensing information, which makes it hard for compliance tools to determine the correct license. By default are files without license information under the default license of the kernel, which is GPLV2. Marking them GPLV2 would exclude them from being included in non GPLV2 code, which is obviously not intended. The user space API headers fall under the syscall exception which is in the kernels COPYING file: 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". otherwise syscall usage would not be possible. Update the files which contain no license information with an SPDX license identifier. The chosen identifier is 'GPL-2.0 WITH Linux-syscall-note' which is the officially assigned identifier for the Linux syscall exception. SPDX license identifiers are a legally binding shorthand, which can be used instead of the full boiler plate text. 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 21:08:43 +07:00
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef _UAPI_LINUX_SCHED_H
#define _UAPI_LINUX_SCHED_H
fork: add clone3 This adds the clone3 system call. As mentioned several times already (cf. [7], [8]) here's the promised patchset for clone3(). We recently merged the CLONE_PIDFD patchset (cf. [1]). It took the last free flag from clone(). Independent of the CLONE_PIDFD patchset a time namespace has been discussed at Linux Plumber Conference last year and has been sent out and reviewed (cf. [5]). It is expected that it will go upstream in the not too distant future. However, it relies on the addition of the CLONE_NEWTIME flag to clone(). The only other good candidate - CLONE_DETACHED - is currently not recyclable as we have identified at least two large or widely used codebases that currently pass this flag (cf. [2], [3], and [4]). Given that CLONE_PIDFD grabbed the last clone() flag the time namespace is effectively blocked. clone3() has the advantage that it will unblock this patchset again. In general, clone3() is extensible and allows for the implementation of new features. The idea is to keep clone3() very simple and close to the original clone(), specifically, to keep on supporting old clone()-based workloads. We know there have been various creative proposals how a new process creation syscall or even api is supposed to look like. Some people even going so far as to argue that the traditional fork()+exec() split should be abandoned in favor of an in-kernel version of spawn(). Independent of whether or not we personally think spawn() is a good idea this patchset has and does not want to have anything to do with this. One stance we take is that there's no real good alternative to clone()+exec() and we need and want to support this model going forward; independent of spawn(). The following requirements guided clone3(): - bump the number of available flags - move arguments that are currently passed as separate arguments in clone() into a dedicated struct clone_args - choose a struct layout that is easy to handle on 32 and on 64 bit - choose a struct layout that is extensible - give new flags that currently need to abuse another flag's dedicated return argument in clone() their own dedicated return argument (e.g. CLONE_PIDFD) - use a separate kernel internal struct kernel_clone_args that is properly typed according to current kernel conventions in fork.c and is different from the uapi struct clone_args - port _do_fork() to use kernel_clone_args so that all process creation syscalls such as fork(), vfork(), clone(), and clone3() behave identical (Arnd suggested, that we can probably also port do_fork() itself in a separate patchset.) - ease of transition for userspace from clone() to clone3() This very much means that we do *not* remove functionality that userspace currently relies on as the latter is a good way of creating a syscall that won't be adopted. - do not try to be clever or complex: keep clone3() as dumb as possible In accordance with Linus suggestions (cf. [11]), clone3() has the following signature: /* uapi */ struct clone_args { __aligned_u64 flags; __aligned_u64 pidfd; __aligned_u64 child_tid; __aligned_u64 parent_tid; __aligned_u64 exit_signal; __aligned_u64 stack; __aligned_u64 stack_size; __aligned_u64 tls; }; /* kernel internal */ struct kernel_clone_args { u64 flags; int __user *pidfd; int __user *child_tid; int __user *parent_tid; int exit_signal; unsigned long stack; unsigned long stack_size; unsigned long tls; }; long sys_clone3(struct clone_args __user *uargs, size_t size) clone3() cleanly supports all of the supported flags from clone() and thus all legacy workloads. The advantage of sticking close to the old clone() is the low cost for userspace to switch to this new api. Quite a lot of userspace apis (e.g. pthreads) are based on the clone() syscall. With the new clone3() syscall supporting all of the old workloads and opening up the ability to add new features should make switching to it for userspace more appealing. In essence, glibc can just write a simple wrapper to switch from clone() to clone3(). There has been some interest in this patchset already. We have received a patch from the CRIU corner for clone3() that would set the PID/TID of a restored process without /proc/sys/kernel/ns_last_pid to eliminate a race. /* User visible differences to legacy clone() */ - CLONE_DETACHED will cause EINVAL with clone3() - CSIGNAL is deprecated It is superseeded by a dedicated "exit_signal" argument in struct clone_args freeing up space for additional flags. This is based on a suggestion from Andrei and Linus (cf. [9] and [10]) /* References */ [1]: b3e5838252665ee4cfa76b82bdf1198dca81e5be [2]: https://dxr.mozilla.org/mozilla-central/source/security/sandbox/linux/SandboxFilter.cpp#343 [3]: https://git.musl-libc.org/cgit/musl/tree/src/thread/pthread_create.c#n233 [4]: https://sources.debian.org/src/blcr/0.8.5-2.3/cr_module/cr_dump_self.c/?hl=740#L740 [5]: https://lore.kernel.org/lkml/20190425161416.26600-1-dima@arista.com/ [6]: https://lore.kernel.org/lkml/20190425161416.26600-2-dima@arista.com/ [7]: https://lore.kernel.org/lkml/CAHrFyr5HxpGXA2YrKza-oB-GGwJCqwPfyhD-Y5wbktWZdt0sGQ@mail.gmail.com/ [8]: https://lore.kernel.org/lkml/20190524102756.qjsjxukuq2f4t6bo@brauner.io/ [9]: https://lore.kernel.org/lkml/20190529222414.GA6492@gmail.com/ [10]: https://lore.kernel.org/lkml/CAHk-=whQP-Ykxi=zSYaV9iXsHsENa+2fdj-zYKwyeyed63Lsfw@mail.gmail.com/ [11]: https://lore.kernel.org/lkml/CAHk-=wieuV4hGwznPsX-8E0G2FKhx3NjZ9X3dTKh5zKd+iqOBw@mail.gmail.com/ Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Christian Brauner <christian@brauner.io> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Serge Hallyn <serge@hallyn.com> Cc: Kees Cook <keescook@chromium.org> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Jann Horn <jannh@google.com> Cc: David Howells <dhowells@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Adrian Reber <adrian@lisas.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrei Vagin <avagin@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Florian Weimer <fweimer@redhat.com> Cc: linux-api@vger.kernel.org
2019-05-25 16:36:41 +07:00
#include <linux/types.h>
/*
* cloning flags:
*/
#define CSIGNAL 0x000000ff /* signal mask to be sent at exit */
#define CLONE_VM 0x00000100 /* set if VM shared between processes */
#define CLONE_FS 0x00000200 /* set if fs info shared between processes */
#define CLONE_FILES 0x00000400 /* set if open files shared between processes */
#define CLONE_SIGHAND 0x00000800 /* set if signal handlers and blocked signals shared */
clone: add CLONE_PIDFD This patchset makes it possible to retrieve pid file descriptors at process creation time by introducing the new flag CLONE_PIDFD to the clone() system call. Linus originally suggested to implement this as a new flag to clone() instead of making it a separate system call. As spotted by Linus, there is exactly one bit for clone() left. CLONE_PIDFD creates file descriptors based on the anonymous inode implementation in the kernel that will also be used to implement the new mount api. They serve as a simple opaque handle on pids. Logically, this makes it possible to interpret a pidfd differently, narrowing or widening the scope of various operations (e.g. signal sending). Thus, a pidfd cannot just refer to a tgid, but also a tid, or in theory - given appropriate flag arguments in relevant syscalls - a process group or session. A pidfd does not represent a privilege. This does not imply it cannot ever be that way but for now this is not the case. A pidfd comes with additional information in fdinfo if the kernel supports procfs. The fdinfo file contains the pid of the process in the callers pid namespace in the same format as the procfs status file, i.e. "Pid:\t%d". As suggested by Oleg, with CLONE_PIDFD the pidfd is returned in the parent_tidptr argument of clone. This has the advantage that we can give back the associated pid and the pidfd at the same time. To remove worries about missing metadata access this patchset comes with a sample program that illustrates how a combination of CLONE_PIDFD, and pidfd_send_signal() can be used to gain race-free access to process metadata through /proc/<pid>. The sample program can easily be translated into a helper that would be suitable for inclusion in libc so that users don't have to worry about writing it themselves. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Christian Brauner <christian@brauner.io> Co-developed-by: Jann Horn <jannh@google.com> Signed-off-by: Jann Horn <jannh@google.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Kees Cook <keescook@chromium.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: David Howells <dhowells@redhat.com> Cc: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> Cc: Andy Lutomirsky <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk>
2019-03-27 19:04:15 +07:00
#define CLONE_PIDFD 0x00001000 /* set if a pidfd should be placed in parent */
#define CLONE_PTRACE 0x00002000 /* set if we want to let tracing continue on the child too */
#define CLONE_VFORK 0x00004000 /* set if the parent wants the child to wake it up on mm_release */
#define CLONE_PARENT 0x00008000 /* set if we want to have the same parent as the cloner */
#define CLONE_THREAD 0x00010000 /* Same thread group? */
#define CLONE_NEWNS 0x00020000 /* New mount namespace group */
#define CLONE_SYSVSEM 0x00040000 /* share system V SEM_UNDO semantics */
#define CLONE_SETTLS 0x00080000 /* create a new TLS for the child */
#define CLONE_PARENT_SETTID 0x00100000 /* set the TID in the parent */
#define CLONE_CHILD_CLEARTID 0x00200000 /* clear the TID in the child */
#define CLONE_DETACHED 0x00400000 /* Unused, ignored */
#define CLONE_UNTRACED 0x00800000 /* set if the tracing process can't force CLONE_PTRACE on this clone */
#define CLONE_CHILD_SETTID 0x01000000 /* set the TID in the child */
#define CLONE_NEWCGROUP 0x02000000 /* New cgroup namespace */
#define CLONE_NEWUTS 0x04000000 /* New utsname namespace */
#define CLONE_NEWIPC 0x08000000 /* New ipc namespace */
#define CLONE_NEWUSER 0x10000000 /* New user namespace */
#define CLONE_NEWPID 0x20000000 /* New pid namespace */
#define CLONE_NEWNET 0x40000000 /* New network namespace */
#define CLONE_IO 0x80000000 /* Clone io context */
clone3: add CLONE_CLEAR_SIGHAND Reset all signal handlers of the child not set to SIG_IGN to SIG_DFL. Mutually exclusive with CLONE_SIGHAND to not disturb other thread's signal handler. In the spirit of closer cooperation between glibc developers and kernel developers (cf. [2]) this patchset came out of a discussion on the glibc mailing list for improving posix_spawn() (cf. [1], [3], [4]). Kernel support for this feature has been explicitly requested by glibc and I see no reason not to help them with this. The child helper process on Linux posix_spawn must ensure that no signal handlers are enabled, so the signal disposition must be either SIG_DFL or SIG_IGN. However, it requires a sigprocmask to obtain the current signal mask and at least _NSIG sigaction calls to reset the signal handlers for each posix_spawn call or complex state tracking that might lead to data corruption in glibc. Adding this flags lets glibc avoid these problems. [1]: https://www.sourceware.org/ml/libc-alpha/2019-10/msg00149.html [3]: https://www.sourceware.org/ml/libc-alpha/2019-10/msg00158.html [4]: https://www.sourceware.org/ml/libc-alpha/2019-10/msg00160.html [2]: https://lwn.net/Articles/799331/ '[...] by asking for better cooperation with the C-library projects in general. They should be copied on patches containing ABI changes, for example. I noted that there are often times where C-library developers wish the kernel community had done things differently; how could those be avoided in the future? Members of the audience suggested that more glibc developers should perhaps join the linux-api list. The other suggestion was to "copy Florian on everything".' Cc: Florian Weimer <fweimer@redhat.com> Cc: libc-alpha@sourceware.org Cc: linux-api@vger.kernel.org Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Link: https://lore.kernel.org/r/20191014104538.3096-1-christian.brauner@ubuntu.com
2019-10-14 17:45:37 +07:00
/* Flags for the clone3() syscall. */
#define CLONE_CLEAR_SIGHAND 0x100000000ULL /* Clear any signal handler and reset to SIG_DFL. */
#ifndef __ASSEMBLY__
/**
* struct clone_args - arguments for the clone3 syscall
fork: extend clone3() to support setting a PID The main motivation to add set_tid to clone3() is CRIU. To restore a process with the same PID/TID CRIU currently uses /proc/sys/kernel/ns_last_pid. It writes the desired (PID - 1) to ns_last_pid and then (quickly) does a clone(). This works most of the time, but it is racy. It is also slow as it requires multiple syscalls. Extending clone3() to support *set_tid makes it possible restore a process using CRIU without accessing /proc/sys/kernel/ns_last_pid and race free (as long as the desired PID/TID is available). This clone3() extension places the same restrictions (CAP_SYS_ADMIN) on clone3() with *set_tid as they are currently in place for ns_last_pid. The original version of this change was using a single value for set_tid. At the 2019 LPC, after presenting set_tid, it was, however, decided to change set_tid to an array to enable setting the PID of a process in multiple PID namespaces at the same time. If a process is created in a PID namespace it is possible to influence the PID inside and outside of the PID namespace. Details also in the corresponding selftest. To create a process with the following PIDs: PID NS level Requested PID 0 (host) 31496 1 42 2 1 For that example the two newly introduced parameters to struct clone_args (set_tid and set_tid_size) would need to be: set_tid[0] = 1; set_tid[1] = 42; set_tid[2] = 31496; set_tid_size = 3; If only the PIDs of the two innermost nested PID namespaces should be defined it would look like this: set_tid[0] = 1; set_tid[1] = 42; set_tid_size = 2; The PID of the newly created process would then be the next available free PID in the PID namespace level 0 (host) and 42 in the PID namespace at level 1 and the PID of the process in the innermost PID namespace would be 1. The set_tid array is used to specify the PID of a process starting from the innermost nested PID namespaces up to set_tid_size PID namespaces. set_tid_size cannot be larger then the current PID namespace level. Signed-off-by: Adrian Reber <areber@redhat.com> Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Acked-by: Andrei Vagin <avagin@gmail.com> Link: https://lore.kernel.org/r/20191115123621.142252-1-areber@redhat.com Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2019-11-15 19:36:20 +07:00
* @flags: Flags for the new process as listed above.
* All flags are valid except for CSIGNAL and
* CLONE_DETACHED.
* @pidfd: If CLONE_PIDFD is set, a pidfd will be
* returned in this argument.
* @child_tid: If CLONE_CHILD_SETTID is set, the TID of the
* child process will be returned in the child's
* memory.
* @parent_tid: If CLONE_PARENT_SETTID is set, the TID of
* the child process will be returned in the
* parent's memory.
* @exit_signal: The exit_signal the parent process will be
* sent when the child exits.
* @stack: Specify the location of the stack for the
* child process.
threads-v5.5 -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCXdfjBwAKCRCRxhvAZXjc onCBAP47WZ/ie7yjoDWhOI1QB7II3NGSzToakxpgJaWoB+NjTwEA7PGrSYVEbPrf pUhiEaEJ29t+cWUxX3+yDO+k7SA6BAY= =Ra58 -----END PGP SIGNATURE----- Merge tag 'threads-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux Pull thread management updates from Christian Brauner: - A pidfd's fdinfo file currently contains the field "Pid:\t<pid>" where <pid> is the pid of the process in the pid namespace of the procfs instance the fdinfo file for the pidfd was opened in. The fdinfo file has now gained a new "NSpid:\t<ns-pid1>[\t<ns-pid2>[...]]" field which lists the pids of the process in all child pid namespaces provided the pid namespace of the procfs instance it is looked up under has an ancestoral relationship with the pid namespace of the process. If it does not 0 will be shown and no further pid namespaces will be listed. Tests included. (Christian Kellner) - If the process the pidfd references has already exited, print -1 for the Pid and NSpid fields in the pidfd's fdinfo file. Tests included. (me) - Add CLONE_CLEAR_SIGHAND. This lets callers clear all signal handler that are not SIG_DFL or SIG_IGN at process creation time. This originated as a feature request from glibc to improve performance and elimate races in their posix_spawn() implementation. Tests included. (me) - Add support for choosing a specific pid for a process with clone3(). This is the feature which was part of the thread update for v5.4 but after a discussion at LPC in Lisbon we decided to delay it for one more cycle in order to make the interface more generic. This has now done. It is now possible to choose a specific pid in a whole pid namespaces (sub)hierarchy instead of just one pid namespace. In order to choose a specific pid the caller must have CAP_SYS_ADMIN in all owning user namespaces of the target pid namespaces. Tests included. (Adrian Reber) - Test improvements and extensions. (Andrei Vagin, me) * tag 'threads-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: selftests/clone3: skip if clone3() is ENOSYS selftests/clone3: check that all pids are released on error paths selftests/clone3: report a correct number of fails selftests/clone3: flush stdout and stderr before clone3() and _exit() selftests: add tests for clone3() with *set_tid fork: extend clone3() to support setting a PID selftests: add tests for clone3() tests: test CLONE_CLEAR_SIGHAND clone3: add CLONE_CLEAR_SIGHAND pid: use pid_has_task() in pidfd_open() exit: use pid_has_task() in do_wait() pid: use pid_has_task() in __change_pid() test: verify fdinfo for pidfd of reaped process pidfd: check pid has attached task in fdinfo pidfd: add tests for NSpid info in fdinfo pidfd: add NSpid entries to fdinfo
2019-11-26 09:36:49 +07:00
* Note, @stack is expected to point to the
* lowest address. The stack direction will be
* determined by the kernel and set up
* appropriately based on @stack_size.
fork: extend clone3() to support setting a PID The main motivation to add set_tid to clone3() is CRIU. To restore a process with the same PID/TID CRIU currently uses /proc/sys/kernel/ns_last_pid. It writes the desired (PID - 1) to ns_last_pid and then (quickly) does a clone(). This works most of the time, but it is racy. It is also slow as it requires multiple syscalls. Extending clone3() to support *set_tid makes it possible restore a process using CRIU without accessing /proc/sys/kernel/ns_last_pid and race free (as long as the desired PID/TID is available). This clone3() extension places the same restrictions (CAP_SYS_ADMIN) on clone3() with *set_tid as they are currently in place for ns_last_pid. The original version of this change was using a single value for set_tid. At the 2019 LPC, after presenting set_tid, it was, however, decided to change set_tid to an array to enable setting the PID of a process in multiple PID namespaces at the same time. If a process is created in a PID namespace it is possible to influence the PID inside and outside of the PID namespace. Details also in the corresponding selftest. To create a process with the following PIDs: PID NS level Requested PID 0 (host) 31496 1 42 2 1 For that example the two newly introduced parameters to struct clone_args (set_tid and set_tid_size) would need to be: set_tid[0] = 1; set_tid[1] = 42; set_tid[2] = 31496; set_tid_size = 3; If only the PIDs of the two innermost nested PID namespaces should be defined it would look like this: set_tid[0] = 1; set_tid[1] = 42; set_tid_size = 2; The PID of the newly created process would then be the next available free PID in the PID namespace level 0 (host) and 42 in the PID namespace at level 1 and the PID of the process in the innermost PID namespace would be 1. The set_tid array is used to specify the PID of a process starting from the innermost nested PID namespaces up to set_tid_size PID namespaces. set_tid_size cannot be larger then the current PID namespace level. Signed-off-by: Adrian Reber <areber@redhat.com> Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Acked-by: Andrei Vagin <avagin@gmail.com> Link: https://lore.kernel.org/r/20191115123621.142252-1-areber@redhat.com Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2019-11-15 19:36:20 +07:00
* @stack_size: The size of the stack for the child process.
* @tls: If CLONE_SETTLS is set, the tls descriptor
* is set to tls.
* @set_tid: Pointer to an array of type *pid_t. The size
* of the array is defined using @set_tid_size.
* This array is used to select PIDs/TIDs for
* newly created processes. The first element in
* this defines the PID in the most nested PID
* namespace. Each additional element in the array
* defines the PID in the parent PID namespace of
* the original PID namespace. If the array has
* less entries than the number of currently
* nested PID namespaces only the PIDs in the
* corresponding namespaces are set.
* @set_tid_size: This defines the size of the array referenced
* in @set_tid. This cannot be larger than the
* kernel's limit of nested PID namespaces.
*
* The structure is versioned by size and thus extensible.
* New struct members must go at the end of the struct and
* must be properly 64bit aligned.
fork: add clone3 This adds the clone3 system call. As mentioned several times already (cf. [7], [8]) here's the promised patchset for clone3(). We recently merged the CLONE_PIDFD patchset (cf. [1]). It took the last free flag from clone(). Independent of the CLONE_PIDFD patchset a time namespace has been discussed at Linux Plumber Conference last year and has been sent out and reviewed (cf. [5]). It is expected that it will go upstream in the not too distant future. However, it relies on the addition of the CLONE_NEWTIME flag to clone(). The only other good candidate - CLONE_DETACHED - is currently not recyclable as we have identified at least two large or widely used codebases that currently pass this flag (cf. [2], [3], and [4]). Given that CLONE_PIDFD grabbed the last clone() flag the time namespace is effectively blocked. clone3() has the advantage that it will unblock this patchset again. In general, clone3() is extensible and allows for the implementation of new features. The idea is to keep clone3() very simple and close to the original clone(), specifically, to keep on supporting old clone()-based workloads. We know there have been various creative proposals how a new process creation syscall or even api is supposed to look like. Some people even going so far as to argue that the traditional fork()+exec() split should be abandoned in favor of an in-kernel version of spawn(). Independent of whether or not we personally think spawn() is a good idea this patchset has and does not want to have anything to do with this. One stance we take is that there's no real good alternative to clone()+exec() and we need and want to support this model going forward; independent of spawn(). The following requirements guided clone3(): - bump the number of available flags - move arguments that are currently passed as separate arguments in clone() into a dedicated struct clone_args - choose a struct layout that is easy to handle on 32 and on 64 bit - choose a struct layout that is extensible - give new flags that currently need to abuse another flag's dedicated return argument in clone() their own dedicated return argument (e.g. CLONE_PIDFD) - use a separate kernel internal struct kernel_clone_args that is properly typed according to current kernel conventions in fork.c and is different from the uapi struct clone_args - port _do_fork() to use kernel_clone_args so that all process creation syscalls such as fork(), vfork(), clone(), and clone3() behave identical (Arnd suggested, that we can probably also port do_fork() itself in a separate patchset.) - ease of transition for userspace from clone() to clone3() This very much means that we do *not* remove functionality that userspace currently relies on as the latter is a good way of creating a syscall that won't be adopted. - do not try to be clever or complex: keep clone3() as dumb as possible In accordance with Linus suggestions (cf. [11]), clone3() has the following signature: /* uapi */ struct clone_args { __aligned_u64 flags; __aligned_u64 pidfd; __aligned_u64 child_tid; __aligned_u64 parent_tid; __aligned_u64 exit_signal; __aligned_u64 stack; __aligned_u64 stack_size; __aligned_u64 tls; }; /* kernel internal */ struct kernel_clone_args { u64 flags; int __user *pidfd; int __user *child_tid; int __user *parent_tid; int exit_signal; unsigned long stack; unsigned long stack_size; unsigned long tls; }; long sys_clone3(struct clone_args __user *uargs, size_t size) clone3() cleanly supports all of the supported flags from clone() and thus all legacy workloads. The advantage of sticking close to the old clone() is the low cost for userspace to switch to this new api. Quite a lot of userspace apis (e.g. pthreads) are based on the clone() syscall. With the new clone3() syscall supporting all of the old workloads and opening up the ability to add new features should make switching to it for userspace more appealing. In essence, glibc can just write a simple wrapper to switch from clone() to clone3(). There has been some interest in this patchset already. We have received a patch from the CRIU corner for clone3() that would set the PID/TID of a restored process without /proc/sys/kernel/ns_last_pid to eliminate a race. /* User visible differences to legacy clone() */ - CLONE_DETACHED will cause EINVAL with clone3() - CSIGNAL is deprecated It is superseeded by a dedicated "exit_signal" argument in struct clone_args freeing up space for additional flags. This is based on a suggestion from Andrei and Linus (cf. [9] and [10]) /* References */ [1]: b3e5838252665ee4cfa76b82bdf1198dca81e5be [2]: https://dxr.mozilla.org/mozilla-central/source/security/sandbox/linux/SandboxFilter.cpp#343 [3]: https://git.musl-libc.org/cgit/musl/tree/src/thread/pthread_create.c#n233 [4]: https://sources.debian.org/src/blcr/0.8.5-2.3/cr_module/cr_dump_self.c/?hl=740#L740 [5]: https://lore.kernel.org/lkml/20190425161416.26600-1-dima@arista.com/ [6]: https://lore.kernel.org/lkml/20190425161416.26600-2-dima@arista.com/ [7]: https://lore.kernel.org/lkml/CAHrFyr5HxpGXA2YrKza-oB-GGwJCqwPfyhD-Y5wbktWZdt0sGQ@mail.gmail.com/ [8]: https://lore.kernel.org/lkml/20190524102756.qjsjxukuq2f4t6bo@brauner.io/ [9]: https://lore.kernel.org/lkml/20190529222414.GA6492@gmail.com/ [10]: https://lore.kernel.org/lkml/CAHk-=whQP-Ykxi=zSYaV9iXsHsENa+2fdj-zYKwyeyed63Lsfw@mail.gmail.com/ [11]: https://lore.kernel.org/lkml/CAHk-=wieuV4hGwznPsX-8E0G2FKhx3NjZ9X3dTKh5zKd+iqOBw@mail.gmail.com/ Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Christian Brauner <christian@brauner.io> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Serge Hallyn <serge@hallyn.com> Cc: Kees Cook <keescook@chromium.org> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Jann Horn <jannh@google.com> Cc: David Howells <dhowells@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Adrian Reber <adrian@lisas.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrei Vagin <avagin@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Florian Weimer <fweimer@redhat.com> Cc: linux-api@vger.kernel.org
2019-05-25 16:36:41 +07:00
*/
struct clone_args {
__aligned_u64 flags;
__aligned_u64 pidfd;
__aligned_u64 child_tid;
__aligned_u64 parent_tid;
__aligned_u64 exit_signal;
__aligned_u64 stack;
__aligned_u64 stack_size;
__aligned_u64 tls;
fork: extend clone3() to support setting a PID The main motivation to add set_tid to clone3() is CRIU. To restore a process with the same PID/TID CRIU currently uses /proc/sys/kernel/ns_last_pid. It writes the desired (PID - 1) to ns_last_pid and then (quickly) does a clone(). This works most of the time, but it is racy. It is also slow as it requires multiple syscalls. Extending clone3() to support *set_tid makes it possible restore a process using CRIU without accessing /proc/sys/kernel/ns_last_pid and race free (as long as the desired PID/TID is available). This clone3() extension places the same restrictions (CAP_SYS_ADMIN) on clone3() with *set_tid as they are currently in place for ns_last_pid. The original version of this change was using a single value for set_tid. At the 2019 LPC, after presenting set_tid, it was, however, decided to change set_tid to an array to enable setting the PID of a process in multiple PID namespaces at the same time. If a process is created in a PID namespace it is possible to influence the PID inside and outside of the PID namespace. Details also in the corresponding selftest. To create a process with the following PIDs: PID NS level Requested PID 0 (host) 31496 1 42 2 1 For that example the two newly introduced parameters to struct clone_args (set_tid and set_tid_size) would need to be: set_tid[0] = 1; set_tid[1] = 42; set_tid[2] = 31496; set_tid_size = 3; If only the PIDs of the two innermost nested PID namespaces should be defined it would look like this: set_tid[0] = 1; set_tid[1] = 42; set_tid_size = 2; The PID of the newly created process would then be the next available free PID in the PID namespace level 0 (host) and 42 in the PID namespace at level 1 and the PID of the process in the innermost PID namespace would be 1. The set_tid array is used to specify the PID of a process starting from the innermost nested PID namespaces up to set_tid_size PID namespaces. set_tid_size cannot be larger then the current PID namespace level. Signed-off-by: Adrian Reber <areber@redhat.com> Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Acked-by: Andrei Vagin <avagin@gmail.com> Link: https://lore.kernel.org/r/20191115123621.142252-1-areber@redhat.com Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2019-11-15 19:36:20 +07:00
__aligned_u64 set_tid;
__aligned_u64 set_tid_size;
fork: add clone3 This adds the clone3 system call. As mentioned several times already (cf. [7], [8]) here's the promised patchset for clone3(). We recently merged the CLONE_PIDFD patchset (cf. [1]). It took the last free flag from clone(). Independent of the CLONE_PIDFD patchset a time namespace has been discussed at Linux Plumber Conference last year and has been sent out and reviewed (cf. [5]). It is expected that it will go upstream in the not too distant future. However, it relies on the addition of the CLONE_NEWTIME flag to clone(). The only other good candidate - CLONE_DETACHED - is currently not recyclable as we have identified at least two large or widely used codebases that currently pass this flag (cf. [2], [3], and [4]). Given that CLONE_PIDFD grabbed the last clone() flag the time namespace is effectively blocked. clone3() has the advantage that it will unblock this patchset again. In general, clone3() is extensible and allows for the implementation of new features. The idea is to keep clone3() very simple and close to the original clone(), specifically, to keep on supporting old clone()-based workloads. We know there have been various creative proposals how a new process creation syscall or even api is supposed to look like. Some people even going so far as to argue that the traditional fork()+exec() split should be abandoned in favor of an in-kernel version of spawn(). Independent of whether or not we personally think spawn() is a good idea this patchset has and does not want to have anything to do with this. One stance we take is that there's no real good alternative to clone()+exec() and we need and want to support this model going forward; independent of spawn(). The following requirements guided clone3(): - bump the number of available flags - move arguments that are currently passed as separate arguments in clone() into a dedicated struct clone_args - choose a struct layout that is easy to handle on 32 and on 64 bit - choose a struct layout that is extensible - give new flags that currently need to abuse another flag's dedicated return argument in clone() their own dedicated return argument (e.g. CLONE_PIDFD) - use a separate kernel internal struct kernel_clone_args that is properly typed according to current kernel conventions in fork.c and is different from the uapi struct clone_args - port _do_fork() to use kernel_clone_args so that all process creation syscalls such as fork(), vfork(), clone(), and clone3() behave identical (Arnd suggested, that we can probably also port do_fork() itself in a separate patchset.) - ease of transition for userspace from clone() to clone3() This very much means that we do *not* remove functionality that userspace currently relies on as the latter is a good way of creating a syscall that won't be adopted. - do not try to be clever or complex: keep clone3() as dumb as possible In accordance with Linus suggestions (cf. [11]), clone3() has the following signature: /* uapi */ struct clone_args { __aligned_u64 flags; __aligned_u64 pidfd; __aligned_u64 child_tid; __aligned_u64 parent_tid; __aligned_u64 exit_signal; __aligned_u64 stack; __aligned_u64 stack_size; __aligned_u64 tls; }; /* kernel internal */ struct kernel_clone_args { u64 flags; int __user *pidfd; int __user *child_tid; int __user *parent_tid; int exit_signal; unsigned long stack; unsigned long stack_size; unsigned long tls; }; long sys_clone3(struct clone_args __user *uargs, size_t size) clone3() cleanly supports all of the supported flags from clone() and thus all legacy workloads. The advantage of sticking close to the old clone() is the low cost for userspace to switch to this new api. Quite a lot of userspace apis (e.g. pthreads) are based on the clone() syscall. With the new clone3() syscall supporting all of the old workloads and opening up the ability to add new features should make switching to it for userspace more appealing. In essence, glibc can just write a simple wrapper to switch from clone() to clone3(). There has been some interest in this patchset already. We have received a patch from the CRIU corner for clone3() that would set the PID/TID of a restored process without /proc/sys/kernel/ns_last_pid to eliminate a race. /* User visible differences to legacy clone() */ - CLONE_DETACHED will cause EINVAL with clone3() - CSIGNAL is deprecated It is superseeded by a dedicated "exit_signal" argument in struct clone_args freeing up space for additional flags. This is based on a suggestion from Andrei and Linus (cf. [9] and [10]) /* References */ [1]: b3e5838252665ee4cfa76b82bdf1198dca81e5be [2]: https://dxr.mozilla.org/mozilla-central/source/security/sandbox/linux/SandboxFilter.cpp#343 [3]: https://git.musl-libc.org/cgit/musl/tree/src/thread/pthread_create.c#n233 [4]: https://sources.debian.org/src/blcr/0.8.5-2.3/cr_module/cr_dump_self.c/?hl=740#L740 [5]: https://lore.kernel.org/lkml/20190425161416.26600-1-dima@arista.com/ [6]: https://lore.kernel.org/lkml/20190425161416.26600-2-dima@arista.com/ [7]: https://lore.kernel.org/lkml/CAHrFyr5HxpGXA2YrKza-oB-GGwJCqwPfyhD-Y5wbktWZdt0sGQ@mail.gmail.com/ [8]: https://lore.kernel.org/lkml/20190524102756.qjsjxukuq2f4t6bo@brauner.io/ [9]: https://lore.kernel.org/lkml/20190529222414.GA6492@gmail.com/ [10]: https://lore.kernel.org/lkml/CAHk-=whQP-Ykxi=zSYaV9iXsHsENa+2fdj-zYKwyeyed63Lsfw@mail.gmail.com/ [11]: https://lore.kernel.org/lkml/CAHk-=wieuV4hGwznPsX-8E0G2FKhx3NjZ9X3dTKh5zKd+iqOBw@mail.gmail.com/ Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Christian Brauner <christian@brauner.io> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Serge Hallyn <serge@hallyn.com> Cc: Kees Cook <keescook@chromium.org> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Jann Horn <jannh@google.com> Cc: David Howells <dhowells@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Adrian Reber <adrian@lisas.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrei Vagin <avagin@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Florian Weimer <fweimer@redhat.com> Cc: linux-api@vger.kernel.org
2019-05-25 16:36:41 +07:00
};
#endif
fork: add clone3 This adds the clone3 system call. As mentioned several times already (cf. [7], [8]) here's the promised patchset for clone3(). We recently merged the CLONE_PIDFD patchset (cf. [1]). It took the last free flag from clone(). Independent of the CLONE_PIDFD patchset a time namespace has been discussed at Linux Plumber Conference last year and has been sent out and reviewed (cf. [5]). It is expected that it will go upstream in the not too distant future. However, it relies on the addition of the CLONE_NEWTIME flag to clone(). The only other good candidate - CLONE_DETACHED - is currently not recyclable as we have identified at least two large or widely used codebases that currently pass this flag (cf. [2], [3], and [4]). Given that CLONE_PIDFD grabbed the last clone() flag the time namespace is effectively blocked. clone3() has the advantage that it will unblock this patchset again. In general, clone3() is extensible and allows for the implementation of new features. The idea is to keep clone3() very simple and close to the original clone(), specifically, to keep on supporting old clone()-based workloads. We know there have been various creative proposals how a new process creation syscall or even api is supposed to look like. Some people even going so far as to argue that the traditional fork()+exec() split should be abandoned in favor of an in-kernel version of spawn(). Independent of whether or not we personally think spawn() is a good idea this patchset has and does not want to have anything to do with this. One stance we take is that there's no real good alternative to clone()+exec() and we need and want to support this model going forward; independent of spawn(). The following requirements guided clone3(): - bump the number of available flags - move arguments that are currently passed as separate arguments in clone() into a dedicated struct clone_args - choose a struct layout that is easy to handle on 32 and on 64 bit - choose a struct layout that is extensible - give new flags that currently need to abuse another flag's dedicated return argument in clone() their own dedicated return argument (e.g. CLONE_PIDFD) - use a separate kernel internal struct kernel_clone_args that is properly typed according to current kernel conventions in fork.c and is different from the uapi struct clone_args - port _do_fork() to use kernel_clone_args so that all process creation syscalls such as fork(), vfork(), clone(), and clone3() behave identical (Arnd suggested, that we can probably also port do_fork() itself in a separate patchset.) - ease of transition for userspace from clone() to clone3() This very much means that we do *not* remove functionality that userspace currently relies on as the latter is a good way of creating a syscall that won't be adopted. - do not try to be clever or complex: keep clone3() as dumb as possible In accordance with Linus suggestions (cf. [11]), clone3() has the following signature: /* uapi */ struct clone_args { __aligned_u64 flags; __aligned_u64 pidfd; __aligned_u64 child_tid; __aligned_u64 parent_tid; __aligned_u64 exit_signal; __aligned_u64 stack; __aligned_u64 stack_size; __aligned_u64 tls; }; /* kernel internal */ struct kernel_clone_args { u64 flags; int __user *pidfd; int __user *child_tid; int __user *parent_tid; int exit_signal; unsigned long stack; unsigned long stack_size; unsigned long tls; }; long sys_clone3(struct clone_args __user *uargs, size_t size) clone3() cleanly supports all of the supported flags from clone() and thus all legacy workloads. The advantage of sticking close to the old clone() is the low cost for userspace to switch to this new api. Quite a lot of userspace apis (e.g. pthreads) are based on the clone() syscall. With the new clone3() syscall supporting all of the old workloads and opening up the ability to add new features should make switching to it for userspace more appealing. In essence, glibc can just write a simple wrapper to switch from clone() to clone3(). There has been some interest in this patchset already. We have received a patch from the CRIU corner for clone3() that would set the PID/TID of a restored process without /proc/sys/kernel/ns_last_pid to eliminate a race. /* User visible differences to legacy clone() */ - CLONE_DETACHED will cause EINVAL with clone3() - CSIGNAL is deprecated It is superseeded by a dedicated "exit_signal" argument in struct clone_args freeing up space for additional flags. This is based on a suggestion from Andrei and Linus (cf. [9] and [10]) /* References */ [1]: b3e5838252665ee4cfa76b82bdf1198dca81e5be [2]: https://dxr.mozilla.org/mozilla-central/source/security/sandbox/linux/SandboxFilter.cpp#343 [3]: https://git.musl-libc.org/cgit/musl/tree/src/thread/pthread_create.c#n233 [4]: https://sources.debian.org/src/blcr/0.8.5-2.3/cr_module/cr_dump_self.c/?hl=740#L740 [5]: https://lore.kernel.org/lkml/20190425161416.26600-1-dima@arista.com/ [6]: https://lore.kernel.org/lkml/20190425161416.26600-2-dima@arista.com/ [7]: https://lore.kernel.org/lkml/CAHrFyr5HxpGXA2YrKza-oB-GGwJCqwPfyhD-Y5wbktWZdt0sGQ@mail.gmail.com/ [8]: https://lore.kernel.org/lkml/20190524102756.qjsjxukuq2f4t6bo@brauner.io/ [9]: https://lore.kernel.org/lkml/20190529222414.GA6492@gmail.com/ [10]: https://lore.kernel.org/lkml/CAHk-=whQP-Ykxi=zSYaV9iXsHsENa+2fdj-zYKwyeyed63Lsfw@mail.gmail.com/ [11]: https://lore.kernel.org/lkml/CAHk-=wieuV4hGwznPsX-8E0G2FKhx3NjZ9X3dTKh5zKd+iqOBw@mail.gmail.com/ Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Christian Brauner <christian@brauner.io> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Serge Hallyn <serge@hallyn.com> Cc: Kees Cook <keescook@chromium.org> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Jann Horn <jannh@google.com> Cc: David Howells <dhowells@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Adrian Reber <adrian@lisas.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrei Vagin <avagin@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Florian Weimer <fweimer@redhat.com> Cc: linux-api@vger.kernel.org
2019-05-25 16:36:41 +07:00
#define CLONE_ARGS_SIZE_VER0 64 /* sizeof first published struct */
fork: extend clone3() to support setting a PID The main motivation to add set_tid to clone3() is CRIU. To restore a process with the same PID/TID CRIU currently uses /proc/sys/kernel/ns_last_pid. It writes the desired (PID - 1) to ns_last_pid and then (quickly) does a clone(). This works most of the time, but it is racy. It is also slow as it requires multiple syscalls. Extending clone3() to support *set_tid makes it possible restore a process using CRIU without accessing /proc/sys/kernel/ns_last_pid and race free (as long as the desired PID/TID is available). This clone3() extension places the same restrictions (CAP_SYS_ADMIN) on clone3() with *set_tid as they are currently in place for ns_last_pid. The original version of this change was using a single value for set_tid. At the 2019 LPC, after presenting set_tid, it was, however, decided to change set_tid to an array to enable setting the PID of a process in multiple PID namespaces at the same time. If a process is created in a PID namespace it is possible to influence the PID inside and outside of the PID namespace. Details also in the corresponding selftest. To create a process with the following PIDs: PID NS level Requested PID 0 (host) 31496 1 42 2 1 For that example the two newly introduced parameters to struct clone_args (set_tid and set_tid_size) would need to be: set_tid[0] = 1; set_tid[1] = 42; set_tid[2] = 31496; set_tid_size = 3; If only the PIDs of the two innermost nested PID namespaces should be defined it would look like this: set_tid[0] = 1; set_tid[1] = 42; set_tid_size = 2; The PID of the newly created process would then be the next available free PID in the PID namespace level 0 (host) and 42 in the PID namespace at level 1 and the PID of the process in the innermost PID namespace would be 1. The set_tid array is used to specify the PID of a process starting from the innermost nested PID namespaces up to set_tid_size PID namespaces. set_tid_size cannot be larger then the current PID namespace level. Signed-off-by: Adrian Reber <areber@redhat.com> Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Acked-by: Andrei Vagin <avagin@gmail.com> Link: https://lore.kernel.org/r/20191115123621.142252-1-areber@redhat.com Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2019-11-15 19:36:20 +07:00
#define CLONE_ARGS_SIZE_VER1 80 /* sizeof second published struct */
/*
* Scheduling policies
*/
#define SCHED_NORMAL 0
#define SCHED_FIFO 1
#define SCHED_RR 2
#define SCHED_BATCH 3
/* SCHED_ISO: reserved but not implemented yet */
#define SCHED_IDLE 5
sched/deadline: Add SCHED_DEADLINE structures & implementation Introduces the data structures, constants and symbols needed for SCHED_DEADLINE implementation. Core data structure of SCHED_DEADLINE are defined, along with their initializers. Hooks for checking if a task belong to the new policy are also added where they are needed. Adds a scheduling class, in sched/dl.c and a new policy called SCHED_DEADLINE. It is an implementation of the Earliest Deadline First (EDF) scheduling algorithm, augmented with a mechanism (called Constant Bandwidth Server, CBS) that makes it possible to isolate the behaviour of tasks between each other. The typical -deadline task will be made up of a computation phase (instance) which is activated on a periodic or sporadic fashion. The expected (maximum) duration of such computation is called the task's runtime; the time interval by which each instance need to be completed is called the task's relative deadline. The task's absolute deadline is dynamically calculated as the time instant a task (better, an instance) activates plus the relative deadline. The EDF algorithms selects the task with the smallest absolute deadline as the one to be executed first, while the CBS ensures each task to run for at most its runtime every (relative) deadline length time interval, avoiding any interference between different tasks (bandwidth isolation). Thanks to this feature, also tasks that do not strictly comply with the computational model sketched above can effectively use the new policy. To summarize, this patch: - introduces the data structures, constants and symbols needed; - implements the core logic of the scheduling algorithm in the new scheduling class file; - provides all the glue code between the new scheduling class and the core scheduler and refines the interactions between sched/dl and the other existing scheduling classes. Signed-off-by: Dario Faggioli <raistlin@linux.it> Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com> Signed-off-by: Fabio Checconi <fchecconi@gmail.com> Signed-off-by: Juri Lelli <juri.lelli@gmail.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1383831828-15501-4-git-send-email-juri.lelli@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-28 17:14:43 +07:00
#define SCHED_DEADLINE 6
/* Can be ORed in to make sure the process is reverted back to SCHED_NORMAL on fork */
#define SCHED_RESET_ON_FORK 0x40000000
/*
* For the sched_{set,get}attr() calls
*/
#define SCHED_FLAG_RESET_ON_FORK 0x01
#define SCHED_FLAG_RECLAIM 0x02
#define SCHED_FLAG_DL_OVERRUN 0x04
sched/core: Allow sched_setattr() to use the current policy The sched_setattr() syscall mandates that a policy is always specified. This requires to always know which policy a task will have when attributes are configured and this makes it impossible to add more generic task attributes valid across different scheduling policies. Reading the policy before setting generic tasks attributes is racy since we cannot be sure it is not changed concurrently. Introduce the required support to change generic task attributes without affecting the current task policy. This is done by adding an attribute flag (SCHED_FLAG_KEEP_POLICY) to enforce the usage of the current policy. Add support for the SETPARAM_POLICY policy, which is already used by the sched_setparam() POSIX syscall, to the sched_setattr() non-POSIX syscall. Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alessio Balsini <balsini@android.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Perret <quentin.perret@arm.com> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Steve Muckle <smuckle@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Todd Kjos <tkjos@google.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lkml.kernel.org/r/20190621084217.8167-6-patrick.bellasi@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-06-21 15:42:06 +07:00
#define SCHED_FLAG_KEEP_POLICY 0x08
sched/uclamp: Extend sched_setattr() to support utilization clamping The SCHED_DEADLINE scheduling class provides an advanced and formal model to define tasks requirements that can translate into proper decisions for both task placements and frequencies selections. Other classes have a more simplified model based on the POSIX concept of priorities. Such a simple priority based model however does not allow to exploit most advanced features of the Linux scheduler like, for example, driving frequencies selection via the schedutil cpufreq governor. However, also for non SCHED_DEADLINE tasks, it's still interesting to define tasks properties to support scheduler decisions. Utilization clamping exposes to user-space a new set of per-task attributes the scheduler can use as hints about the expected/required utilization for a task. This allows to implement a "proactive" per-task frequency control policy, a more advanced policy than the current one based just on "passive" measured task utilization. For example, it's possible to boost interactive tasks (e.g. to get better performance) or cap background tasks (e.g. to be more energy/thermal efficient). Introduce a new API to set utilization clamping values for a specified task by extending sched_setattr(), a syscall which already allows to define task specific properties for different scheduling classes. A new pair of attributes allows to specify a minimum and maximum utilization the scheduler can consider for a task. Do that by validating the required clamp values before and then applying the required changes using _the_ same pattern already in use for __setscheduler(). This ensures that the task is re-enqueued with the new clamp values. Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alessio Balsini <balsini@android.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Perret <quentin.perret@arm.com> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Steve Muckle <smuckle@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Todd Kjos <tkjos@google.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lkml.kernel.org/r/20190621084217.8167-7-patrick.bellasi@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-06-21 15:42:07 +07:00
#define SCHED_FLAG_KEEP_PARAMS 0x10
#define SCHED_FLAG_UTIL_CLAMP_MIN 0x20
#define SCHED_FLAG_UTIL_CLAMP_MAX 0x40
#define SCHED_FLAG_KEEP_ALL (SCHED_FLAG_KEEP_POLICY | \
SCHED_FLAG_KEEP_PARAMS)
#define SCHED_FLAG_UTIL_CLAMP (SCHED_FLAG_UTIL_CLAMP_MIN | \
SCHED_FLAG_UTIL_CLAMP_MAX)
#define SCHED_FLAG_ALL (SCHED_FLAG_RESET_ON_FORK | \
SCHED_FLAG_RECLAIM | \
sched/core: Allow sched_setattr() to use the current policy The sched_setattr() syscall mandates that a policy is always specified. This requires to always know which policy a task will have when attributes are configured and this makes it impossible to add more generic task attributes valid across different scheduling policies. Reading the policy before setting generic tasks attributes is racy since we cannot be sure it is not changed concurrently. Introduce the required support to change generic task attributes without affecting the current task policy. This is done by adding an attribute flag (SCHED_FLAG_KEEP_POLICY) to enforce the usage of the current policy. Add support for the SETPARAM_POLICY policy, which is already used by the sched_setparam() POSIX syscall, to the sched_setattr() non-POSIX syscall. Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alessio Balsini <balsini@android.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Perret <quentin.perret@arm.com> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Steve Muckle <smuckle@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Todd Kjos <tkjos@google.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lkml.kernel.org/r/20190621084217.8167-6-patrick.bellasi@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-06-21 15:42:06 +07:00
SCHED_FLAG_DL_OVERRUN | \
sched/uclamp: Extend sched_setattr() to support utilization clamping The SCHED_DEADLINE scheduling class provides an advanced and formal model to define tasks requirements that can translate into proper decisions for both task placements and frequencies selections. Other classes have a more simplified model based on the POSIX concept of priorities. Such a simple priority based model however does not allow to exploit most advanced features of the Linux scheduler like, for example, driving frequencies selection via the schedutil cpufreq governor. However, also for non SCHED_DEADLINE tasks, it's still interesting to define tasks properties to support scheduler decisions. Utilization clamping exposes to user-space a new set of per-task attributes the scheduler can use as hints about the expected/required utilization for a task. This allows to implement a "proactive" per-task frequency control policy, a more advanced policy than the current one based just on "passive" measured task utilization. For example, it's possible to boost interactive tasks (e.g. to get better performance) or cap background tasks (e.g. to be more energy/thermal efficient). Introduce a new API to set utilization clamping values for a specified task by extending sched_setattr(), a syscall which already allows to define task specific properties for different scheduling classes. A new pair of attributes allows to specify a minimum and maximum utilization the scheduler can consider for a task. Do that by validating the required clamp values before and then applying the required changes using _the_ same pattern already in use for __setscheduler(). This ensures that the task is re-enqueued with the new clamp values. Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alessio Balsini <balsini@android.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Perret <quentin.perret@arm.com> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Steve Muckle <smuckle@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Todd Kjos <tkjos@google.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lkml.kernel.org/r/20190621084217.8167-7-patrick.bellasi@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-06-21 15:42:07 +07:00
SCHED_FLAG_KEEP_ALL | \
SCHED_FLAG_UTIL_CLAMP)
#endif /* _UAPI_LINUX_SCHED_H */