From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4DFB4455.7050809@domain.hid> Date: Fri, 17 Jun 2011 14:11:01 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <4DFB1E0B.1070903@domain.hid> <4DFB3346.6000405@domain.hid> <4DFB346C.6040607@domain.hid> <1308311928.2270.33.camel@domain.hid> In-Reply-To: <1308311928.2270.33.camel@domain.hid> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-core] [RFC][PATCH] nucleus: Prevent rescheduling while in xntbase_tick List-Id: Xenomai life and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Philippe Gerum Cc: Xenomai core On 2011-06-17 13:58, Philippe Gerum wrote: > On Fri, 2011-06-17 at 13:03 +0200, Jan Kiszka wrote: >> On 2011-06-17 12:58, Gilles Chanteperdrix wrote: >>> On 06/17/2011 11:27 AM, Jan Kiszka wrote: >>>> Based on code inspection, it looks like a timer handler triggering a >>>> reschedule in the path xntbase_tick -> xntimer_tick_aperiodic / >>>> xntimer_tick_periodic_inner -> handler can cause problems, e.g. a >>>> reschedule before all expired timers were processed. The timer core is >>>> usually run atomically from an interrupt handler, so better emulate an >>>> IRQ context inside xntbase_tick by setting XNINIRQ. >>> >>> I do not understand this one either: if we are inside >>> xntimer_tick_aperiodic, XNINIRQ is already set. >> >> Not if you come via xntbase_tick, called by the mentioned skins also >> outside a timer IRQ (at least based on my understanding of that skin >> APIs). But I might be wrong, I just came across this while checking for >> potentially invalid cached xnpod_current_sched values. > > That is ok, ui_timer(), tickAnnounce() and tm_tick() are designed by the > respective RTOS to be called from IRQ context. Fine. Should we add a XENO_ASSERT to set this in stone and for documentation purposes? Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux