Date: Thu, 23 Jan 2020 01:24:47 +0000 (UTC) From: Gleb Smirnoff <glebius@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r357004 - in head/sys: kern sys Message-ID: <202001230124.00N1OlXi029506@repo.freebsd.org>
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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); Modified: head/sys/sys/interrupt.h ============================================================================== --- head/sys/sys/interrupt.h Thu Jan 23 01:20:59 2020 (r357003) +++ head/sys/sys/interrupt.h Thu Jan 23 01:24:47 2020 (r357004) @@ -58,6 +58,7 @@ struct intr_handler { }; /* Interrupt handle flags kept in ih_flags */ +#define IH_NET 0x00000001 /* Network. */ #define IH_EXCLUSIVE 0x00000002 /* Exclusive interrupt. */ #define IH_ENTROPY 0x00000004 /* Device is a good entropy source. */ #define IH_DEAD 0x00000008 /* Handler should be removed. */
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