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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