Date: Thu, 23 Jan 2020 09:36:53 +0100 From: Hans Petter Selasky <hps@selasky.org> To: Gleb Smirnoff <glebius@FreeBSD.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r357004 - in head/sys: kern sys Message-ID: <fb6e84b6-85a9-3252-c27a-bb9ee7ca203f@selasky.org> In-Reply-To: <202001230124.00N1OlXi029506@repo.freebsd.org> References: <202001230124.00N1OlXi029506@repo.freebsd.org>
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On 2020-01-23 02:24, Gleb Smirnoff wrote: > Author: glebius > Date: Thu Jan 23 01:24:47 2020 > New Revision: 357004 > URL: https://svnweb.freebsd.org/changeset/base/357004 > > Log: > Enter the network epoch for interrupt handlers of INTR_TYPE_NET. > > Provide tunable to limit how many times handlers may be executed > without reentering epoch. > > Differential Revision: https://reviews.freebsd.org/D23242 > > Modified: > head/sys/kern/kern_intr.c > head/sys/sys/interrupt.h > > Modified: head/sys/kern/kern_intr.c > ============================================================================== > --- head/sys/kern/kern_intr.c Thu Jan 23 01:20:59 2020 (r357003) > +++ head/sys/kern/kern_intr.c Thu Jan 23 01:24:47 2020 (r357004) > @@ -48,6 +48,7 @@ __FBSDID("$FreeBSD$"); > #include <sys/mutex.h> > #include <sys/priv.h> > #include <sys/proc.h> > +#include <sys/epoch.h> > #include <sys/random.h> > #include <sys/resourcevar.h> > #include <sys/sched.h> > @@ -94,6 +95,9 @@ static int intr_storm_threshold = 0; > SYSCTL_INT(_hw, OID_AUTO, intr_storm_threshold, CTLFLAG_RWTUN, > &intr_storm_threshold, 0, > "Number of consecutive interrupts before storm protection is enabled"); > +static int intr_epoch_batch = 1000; > +SYSCTL_INT(_hw, OID_AUTO, intr_epoch_batch, CTLFLAG_RWTUN, &intr_epoch_batch, > + 0, "Maximum interrupt handler executions without re-entering epoch(9)"); > static TAILQ_HEAD(, intr_event) event_list = > TAILQ_HEAD_INITIALIZER(event_list); > static struct mtx event_lock; > @@ -587,6 +591,8 @@ intr_event_add_handler(struct intr_event *ie, const ch > ih->ih_flags |= IH_MPSAFE; > if (flags & INTR_ENTROPY) > ih->ih_flags |= IH_ENTROPY; > + if (flags & INTR_TYPE_NET) > + ih->ih_flags |= IH_NET; > > /* We can only have one exclusive handler in a event. */ > mtx_lock(&ie->ie_lock); > @@ -1196,11 +1202,12 @@ ithread_execute_handlers(struct proc *p, struct intr_e > static void > ithread_loop(void *arg) > { > + struct epoch_tracker et; > struct intr_thread *ithd; > struct intr_event *ie; > struct thread *td; > struct proc *p; > - int wake; > + int wake, epoch_count; > > td = curthread; > p = td->td_proc; > @@ -1235,8 +1242,21 @@ ithread_loop(void *arg) > * that the load of ih_need in ithread_execute_handlers() > * is ordered after the load of it_need here. > */ > - while (atomic_cmpset_acq_int(&ithd->it_need, 1, 0) != 0) > + if (ie->ie_hflags & IH_NET) { > + epoch_count = 0; > + NET_EPOCH_ENTER(et); > + } > + while (atomic_cmpset_acq_int(&ithd->it_need, 1, 0) != 0) { > ithread_execute_handlers(p, ie); > + if ((ie->ie_hflags & IH_NET) && > + ++epoch_count >= intr_epoch_batch) { > + NET_EPOCH_EXIT(et); > + epoch_count = 0; > + NET_EPOCH_ENTER(et); > + } > + } > + if (ie->ie_hflags & IH_NET) > + NET_EPOCH_EXIT(et); > WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread"); > mtx_assert(&Giant, MA_NOTOWNED); > Beware that iflib uses GROUP TASKs to invoke the RX-path for packet processing and only register a fast IRQ handler. --HPS
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