kernel/init, branch linux-2.6.22.y

disable sys_timerfd()

2007-09-26T17:54:39Z

commit e42601973b1bce1d2987f82159c1ebeaccc6b310 in mainline. There is still some confusion and disagreement over what this interface should actually do. So it is best that we disable it in 2.6.23 until we get that fully sorted out. (sys_timerfd() was present in 2.6.22 but it was apparently broken, so here we assume that nobody is using it yet). Cc: Michael Kerrisk Cc: Davide Libenzi Acked-by: Linus Torvalds Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

init/main: use __init_refok to fix section mismatch

2007-05-19T07:11:58Z

Kill a special case in modpost by introducing the __init_refok marker. Signed-off-by: Sam Ravnborg

SLUB: Remove depends on EXPERIMENTAL and !ARCH_USES_SLAB_PAGE_STRUCT

2007-05-17T12:23:03Z

No arch sets ARCH_USES_SLAB_PAGE_STRUCT anymore. Remove the experimental dependency as well since we want to have it as a real alternative to SLAB. It all comes down to killing a single line from init/Kconfig. Signed-off-by: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

slob: implement RCU freeing

2007-05-17T12:23:02Z

The SLOB allocator should implement SLAB_DESTROY_BY_RCU correctly, because even on UP, RCU freeing semantics are not equivalent to simply freeing immediately. This also allows SLOB to be used on SMP. Signed-off-by: Nick Piggin Acked-by: Matt Mackall Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

signal/timer/event: eventfd core

2007-05-11T15:29:36Z

This is a very simple and light file descriptor, that can be used as event wait/dispatch by userspace (both wait and dispatch) and by the kernel (dispatch only). It can be used instead of pipe(2) in all cases where those would simply be used to signal events. Their kernel overhead is much lower than pipes, and they do not consume two fds. When used in the kernel, it can offer an fd-bridge to enable, for example, functionalities like KAIO or syslets/threadlets to signal to an fd the completion of certain operations. But more in general, an eventfd can be used by the kernel to signal readiness, in a POSIX poll/select way, of interfaces that would otherwise be incompatible with it. The API is: int eventfd(unsigned int count); The eventfd API accepts an initial "count" parameter, and returns an eventfd fd. It supports poll(2) (POLLIN, POLLOUT, POLLERR), read(2) and write(2). The POLLIN flag is raised when the internal counter is greater than zero. The POLLOUT flag is raised when at least a value of "1" can be written to the internal counter. The POLLERR flag is raised when an overflow in the counter value is detected. The write(2) operation can never overflow the counter, since it blocks (unless O_NONBLOCK is set, in which case -EAGAIN is returned). But the eventfd_signal() function can do it, since it's supposed to not sleep during its operation. The read(2) function reads the __u64 counter value, and reset the internal value to zero. If the value read is equal to (__u64) -1, an overflow happened on the internal counter (due to 2^64 eventfd_signal() posts that has never been retired - unlickely, but possible). The write(2) call writes an __u64 count value, and adds it to the current counter. The eventfd fd supports O_NONBLOCK also. On the kernel side, we have: struct file *eventfd_fget(int fd); int eventfd_signal(struct file *file, unsigned int n); The eventfd_fget() should be called to get a struct file* from an eventfd fd (this is an fget() + check of f_op being an eventfd fops pointer). The kernel can then call eventfd_signal() every time it wants to post an event to userspace. The eventfd_signal() function can be called from any context. An eventfd() simple test and bench is available here: http://www.xmailserver.org/eventfd-bench.c This is the eventfd-based version of pipetest-4 (pipe(2) based): http://www.xmailserver.org/pipetest-4.c Not that performance matters much in the eventfd case, but eventfd-bench shows almost as double as performance than pipetest-4. [akpm@linux-foundation.org: fix i386 build] [akpm@linux-foundation.org: add sys_eventfd to sys_ni.c] Signed-off-by: Davide Libenzi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

signal/timer/event: timerfd core

2007-05-11T15:29:36Z

This patch introduces a new system call for timers events delivered though file descriptors. This allows timer event to be used with standard POSIX poll(2), select(2) and read(2). As a consequence of supporting the Linux f_op->poll subsystem, they can be used with epoll(2) too. The system call is defined as: int timerfd(int ufd, int clockid, int flags, const struct itimerspec *utmr); The "ufd" parameter allows for re-use (re-programming) of an existing timerfd w/out going through the close/open cycle (same as signalfd). If "ufd" is -1, s new file descriptor will be created, otherwise the existing "ufd" will be re-programmed. The "clockid" parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME. The time specified in the "utmr->it_value" parameter is the expiry time for the timer. If the TFD_TIMER_ABSTIME flag is set in "flags", this is an absolute time, otherwise it's a relative time. If the time specified in the "utmr->it_interval" is not zero (.tv_sec == 0, tv_nsec == 0), this is the period at which the following ticks should be generated. The "utmr->it_interval" should be set to zero if only one tick is requested. Setting the "utmr->it_value" to zero will disable the timer, or will create a timerfd without the timer enabled. The function returns the new (or same, in case "ufd" is a valid timerfd descriptor) file, or -1 in case of error. As stated before, the timerfd file descriptor supports poll(2), select(2) and epoll(2). When a timer event happened on the timerfd, a POLLIN mask will be returned. The read(2) call can be used, and it will return a u32 variable holding the number of "ticks" that happened on the interface since the last call to read(2). The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN will be returned if no ticks happened. A quick test program, shows timerfd working correctly on my amd64 box: http://www.xmailserver.org/timerfd-test.c [akpm@linux-foundation.org: add sys_timerfd to sys_ni.c] Signed-off-by: Davide Libenzi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

signal/timer/event: signalfd core

2007-05-11T15:29:36Z

This patch series implements the new signalfd() system call. I took part of the original Linus code (and you know how badly it can be broken :), and I added even more breakage ;) Signals are fetched from the same signal queue used by the process, so signalfd will compete with standard kernel delivery in dequeue_signal(). If you want to reliably fetch signals on the signalfd file, you need to block them with sigprocmask(SIG_BLOCK). This seems to be working fine on my Dual Opteron machine. I made a quick test program for it: http://www.xmailserver.org/signafd-test.c The signalfd() system call implements signal delivery into a file descriptor receiver. The signalfd file descriptor if created with the following API: int signalfd(int ufd, const sigset_t *mask, size_t masksize); The "ufd" parameter allows to change an existing signalfd sigmask, w/out going to close/create cycle (Linus idea). Use "ufd" == -1 if you want a brand new signalfd file. The "mask" allows to specify the signal mask of signals that we are interested in. The "masksize" parameter is the size of "mask". The signalfd fd supports the poll(2) and read(2) system calls. The poll(2) will return POLLIN when signals are available to be dequeued. As a direct consequence of supporting the Linux poll subsystem, the signalfd fd can use used together with epoll(2) too. The read(2) system call will return a "struct signalfd_siginfo" structure in the userspace supplied buffer. The return value is the number of bytes copied in the supplied buffer, or -1 in case of error. The read(2) call can also return 0, in case the sighand structure to which the signalfd was attached, has been orphaned. The O_NONBLOCK flag is also supported, and read(2) will return -EAGAIN in case no signal is available. If the size of the buffer passed to read(2) is lower than sizeof(struct signalfd_siginfo), -EINVAL is returned. A read from the signalfd can also return -ERESTARTSYS in case a signal hits the process. The format of the struct signalfd_siginfo is, and the valid fields depends of the (->code & __SI_MASK) value, in the same way a struct siginfo would: struct signalfd_siginfo { __u32 signo; /* si_signo */ __s32 err; /* si_errno */ __s32 code; /* si_code */ __u32 pid; /* si_pid */ __u32 uid; /* si_uid */ __s32 fd; /* si_fd */ __u32 tid; /* si_fd */ __u32 band; /* si_band */ __u32 overrun; /* si_overrun */ __u32 trapno; /* si_trapno */ __s32 status; /* si_status */ __s32 svint; /* si_int */ __u64 svptr; /* si_ptr */ __u64 utime; /* si_utime */ __u64 stime; /* si_stime */ __u64 addr; /* si_addr */ }; [akpm@linux-foundation.org: fix signalfd_copyinfo() on i386] Signed-off-by: Davide Libenzi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

signal/timer/event fds: anonymous inode source

2007-05-11T15:29:36Z

This patch add an anonymous inode source, to be used for files that need and inode only in order to create a file*. We do not care of having an inode for each file, and we do not even care of having different names in the associated dentries (dentry names will be same for classes of file*). This allow code reuse, and will be used by epoll, signalfd and timerfd (and whatever else there'll be). Signed-off-by: Davide Libenzi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Explicitly set pgid and sid of init process

2007-05-11T15:29:35Z

Explicitly set pgid and sid of init process to 1. Signed-off-by: Sukadev Bhattiprolu Cc: Cedric Le Goater Cc: Dave Hansen Cc: Serge Hallyn Cc: Eric Biederman Cc: Herbert Poetzl Cc: Acked-by: Eric W. Biederman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

SLUB: SLUB_DEBUG must depend on SLUB

2007-05-10T16:26:53Z

Otherwise people get asked about SLUB_DEBUG even if they have another slab allocator enabled. Signed-off-by: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds