Re: [patch 09/23] dynticks: extend next_timer_interrupt() to use a reference jiffie

On Fri, 29 Sep 2006 23:58:28 -0000
Thomas Gleixner <[email protected]> wrote:

> From: Thomas Gleixner <[email protected]>
> 
> For CONFIG_NO_HZ we need to calculate the next timer wheel event based
> to a given jiffie value. Extend the existing code to allow the extra now
> argument. Provide a compability function for the existing implementations
> to call the function with now = jiffies.
> This also solves the racyness of the original code vs. jiffies changing
> during the iteration.
> 

I think this change has the potential to significantly increase the hold
time of tvec_base_t.lock.  Quite a lot of code has been moved inside that
lock, but most worrisome is that hrtimer_get_next_event() is also now
inside it.

What workloads is this change likely to impact, and how can we set about
verifying that we aren't introducing a problem?

Was that (unchangelogged) locking change even needed?  If so, why?

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

---

• References:
  • [patch 00/23]
    • From: Thomas Gleixner <[email protected]>
  • [patch 09/23] dynticks: extend next_timer_interrupt() to use a reference jiffie
    • From: Thomas Gleixner <[email protected]>

• Prev by Date: Re: [patch 07/23] cleanup: uninline irq_enter() and move it into a function
• Next by Date: Re: [patch 03/23] GTOD: persistent clock support, i386
• Previous by thread: [patch 09/23] dynticks: extend next_timer_interrupt() to use a reference jiffie
• Next by thread: [patch 19/23] high-res timers, dynticks: enable i386 support
• Index(es):
  • Date
  • Thread

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]