lkml.org 
[lkml]   [2014]   [Jul]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[tip:timers/core] timerfd: Implement show_fdinfo method
    Commit-ID:  af9c4957cf212ad9cf0bee34c95cb11de5426e85
    Gitweb: http://git.kernel.org/tip/af9c4957cf212ad9cf0bee34c95cb11de5426e85
    Author: Cyrill Gorcunov <gorcunov@openvz.org>
    AuthorDate: Wed, 16 Jul 2014 01:54:52 +0400
    Committer: Thomas Gleixner <tglx@linutronix.de>
    CommitDate: Fri, 18 Jul 2014 11:49:57 +0200

    timerfd: Implement show_fdinfo method

    For checkpoint/restore of timerfd files we need to know how exactly
    the timer were armed, to be able to recreate it on restore stage.
    Thus implement show_fdinfo method which provides enough information
    for that.

    One of significant changes I think is the addition of @settime_flags
    member. Currently there are two flags TFD_TIMER_ABSTIME and
    TFD_TIMER_CANCEL_ON_SET, and the second can be found from
    @might_cancel variable but in case if the flags will be extended
    in future we most probably will have to somehow remember them
    explicitly anyway so I guss doing that right now won't hurt.

    To not bloat the timerfd_ctx structure I've converted @expired
    to short integer and defined @settime_flags as short too.

    v2 (by avagin@, vdavydov@ and tglx@):

    - Add it_value/it_interval fields
    - Save flags being used in timerfd_setup in context

    v3 (by tglx@):
    - don't forget to use CONFIG_PROC_FS

    v4 (by akpm@):
    -Use define timerfd_show NULL for non c/r config

    Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Michael Kerrisk <mtk.manpages@gmail.com>
    Cc: Andrey Vagin <avagin@openvz.org>
    Cc: Pavel Emelyanov <xemul@parallels.com>
    Cc: Vladimir Davydov <vdavydov@parallels.com>
    Link: http://lkml.kernel.org/r/20140715215703.114365649@openvz.org
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    ---
    fs/timerfd.c | 34 +++++++++++++++++++++++++++++++++-
    1 file changed, 33 insertions(+), 1 deletion(-)

    diff --git a/fs/timerfd.c b/fs/timerfd.c
    index 0013142..77183f0 100644
    --- a/fs/timerfd.c
    +++ b/fs/timerfd.c
    @@ -35,8 +35,9 @@ struct timerfd_ctx {
    ktime_t moffs;
    wait_queue_head_t wqh;
    u64 ticks;
    - int expired;
    int clockid;
    + short unsigned expired;
    + short unsigned settime_flags; /* to show in fdinfo */
    struct rcu_head rcu;
    struct list_head clist;
    bool might_cancel;
    @@ -196,6 +197,8 @@ static int timerfd_setup(struct timerfd_ctx *ctx, int flags,
    if (timerfd_canceled(ctx))
    return -ECANCELED;
    }
    +
    + ctx->settime_flags = flags & TFD_SETTIME_FLAGS;
    return 0;
    }

    @@ -284,11 +287,40 @@ static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
    return res;
    }

    +#ifdef CONFIG_PROC_FS
    +static int timerfd_show(struct seq_file *m, struct file *file)
    +{
    + struct timerfd_ctx *ctx = file->private_data;
    + struct itimerspec t;
    +
    + spin_lock_irq(&ctx->wqh.lock);
    + t.it_value = ktime_to_timespec(timerfd_get_remaining(ctx));
    + t.it_interval = ktime_to_timespec(ctx->tintv);
    + spin_unlock_irq(&ctx->wqh.lock);
    +
    + return seq_printf(m,
    + "clockid: %d\n"
    + "ticks: %llu\n"
    + "settime flags: 0%o\n"
    + "it_value: (%llu, %llu)\n"
    + "it_interval: (%llu, %llu)\n",
    + ctx->clockid, (unsigned long long)ctx->ticks,
    + ctx->settime_flags,
    + (unsigned long long)t.it_value.tv_sec,
    + (unsigned long long)t.it_value.tv_nsec,
    + (unsigned long long)t.it_interval.tv_sec,
    + (unsigned long long)t.it_interval.tv_nsec);
    +}
    +#else
    +#define timerfd_show NULL
    +#endif
    +
    static const struct file_operations timerfd_fops = {
    .release = timerfd_release,
    .poll = timerfd_poll,
    .read = timerfd_read,
    .llseek = noop_llseek,
    + .show_fdinfo = timerfd_show,
    };

    static int timerfd_fget(int fd, struct fd *p)

    \
     
     \ /
      Last update: 2014-07-18 13:01    [W:5.435 / U:0.016 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site