> -----Original Message----- > From: Burakov, Anatoly <anatoly.bura...@intel.com> > Sent: Thursday, July 18, 2019 6:43 PM > To: Nithin Kumar Dabilpuram <ndabilpu...@marvell.com>; Hyong Youb Kim > <hyon...@cisco.com>; David Marchand <david.march...@redhat.com>; > Thomas Monjalon <tho...@monjalon.net>; Ferruh Yigit > <ferruh.yi...@intel.com>; Bruce Richardson <bruce.richard...@intel.com> > Cc: Jerin Jacob Kollanukkaran <jer...@marvell.com>; John Daley > <johnd...@cisco.com>; Shahed Shaikh <shsha...@marvell.com>; > dev@dpdk.org > Subject: [EXT] Re: [dpdk-dev] [PATCH v3 2/3] eal: add ack interrupt API > On 18-Jul-19 9:46 AM, Nithin Dabilpuram wrote: > > Add new ack interrupt API to avoid using > > VFIO_IRQ_SET_ACTION_TRIGGER(rte_intr_enable()) for acking interrupt > > purpose for VFIO based interrupt handlers. > > This implementation is specific to Linux. > > > > Using rte_intr_enable() for acking interrupt has below issues > > > > * Time consuming to do for every interrupt received as it will > > free_irq() followed by request_irq() and all other initializations > > * A race condition because of a window between free_irq() and > > request_irq() with packet reception still on and device still > > enabled and would throw warning messages like below. > > [158764.159833] do_IRQ: 9.34 No irq handler for vector > > > > In this patch, rte_intr_ack() is a no-op for VFIO_MSIX/VFIO_MSI > > interrupts as they are edge triggered and kernel would not mask the > > interrupt before delivering the event to userspace and we don't need to > ack. > > > > Signed-off-by: Nithin Dabilpuram <ndabilpu...@marvell.com> > > Signed-off-by: Jerin Jacob <jer...@marvell.com> > > Tested-by: Shahed Shaikh <shsha...@marvell.com> > > --- > > <snip> > > > */ > > int rte_intr_disable(const struct rte_intr_handle *intr_handle); > > > > +/** > > + * It acks an interrupt raised for the specified handle. > > + * > > + * Call this function to ack an interrupt from interrupt > > + * handler either from application or driver, so that > > + * new interrupts are raised. > > + * > > + * @note PMD generally calls this function at the end of its IRQ callback. > > + * Internally, it unmasks the interrupt if possible. For INTx, unmasking > > + * is required as the interrupt is auto-masked prior to invoking > > + * callback. For MSI/MSI-X, unmasking is typically not needed as the > > + * interrupt is not auto-masked. In fact, for interrupt handle types > > + * VFIO_MSIX and VFIO_MSI, this function is no-op. > > I've added this comment in previous revision's discussion, but i'll copy it > here > as well. > > Does the user of this API even cares about these details? I would think that > it > would be easier to just mandate calling this function at the end of each > interrupt callback, regardless of which interrupt mode is used. > > IMO internal details (about no-ops and such) are better explained in the > implementation, not in the public-facing API header.
+1 to move the comment under @note to implementation.
