Module Name: src
Committed By: ad
Date: Sun May 17 14:11:30 UTC 2020
Modified Files:
src/sys/kern: kern_softint.c
src/sys/sys: intr.h
Log Message:
softint_disestablish(): use a high priority xcall to determine that the
handler is no longer running.
To generate a diff of this commit:
cvs rdiff -u -r1.65 -r1.66 src/sys/kern/kern_softint.c
cvs rdiff -u -r1.20 -r1.21 src/sys/sys/intr.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/kern_softint.c
diff -u src/sys/kern/kern_softint.c:1.65 src/sys/kern/kern_softint.c:1.66
--- src/sys/kern/kern_softint.c:1.65 Thu Apr 30 20:54:27 2020
+++ src/sys/kern/kern_softint.c Sun May 17 14:11:30 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_softint.c,v 1.65 2020/04/30 20:54:27 skrll Exp $ */
+/* $NetBSD: kern_softint.c,v 1.66 2020/05/17 14:11:30 ad Exp $ */
/*-
* Copyright (c) 2007, 2008, 2019, 2020 The NetBSD Foundation, Inc.
@@ -170,7 +170,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_softint.c,v 1.65 2020/04/30 20:54:27 skrll Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_softint.c,v 1.66 2020/05/17 14:11:30 ad Exp $");
#include <sys/param.h>
#include <sys/proc.h>
@@ -197,6 +197,7 @@ typedef struct softint {
struct evcnt si_evcnt;
struct evcnt si_evcnt_block;
volatile int si_active;
+ int si_ipl;
char si_name[8];
char si_name_block[8+6];
} softint_t;
@@ -230,7 +231,8 @@ static void *softint_netisrs[NETISR_MAX]
* Initialize a single interrupt level for a single CPU.
*/
static void
-softint_init_isr(softcpu_t *sc, const char *desc, pri_t pri, u_int level)
+softint_init_isr(softcpu_t *sc, const char *desc, pri_t pri, u_int level,
+ int ipl)
{
struct cpu_info *ci;
softint_t *si;
@@ -257,6 +259,7 @@ softint_init_isr(softcpu_t *sc, const ch
evcnt_attach_dynamic(&si->si_evcnt_block, EVCNT_TYPE_MISC, NULL,
"softint", si->si_name_block);
+ si->si_ipl = ipl;
si->si_lwp->l_private = si;
softint_init_md(si->si_lwp, level, &si->si_machdep);
}
@@ -292,10 +295,14 @@ softint_init(struct cpu_info *ci)
ci->ci_data.cpu_softints = 0;
sc->sc_cpu = ci;
- softint_init_isr(sc, "net", PRI_SOFTNET, SOFTINT_NET);
- softint_init_isr(sc, "bio", PRI_SOFTBIO, SOFTINT_BIO);
- softint_init_isr(sc, "clk", PRI_SOFTCLOCK, SOFTINT_CLOCK);
- softint_init_isr(sc, "ser", PRI_SOFTSERIAL, SOFTINT_SERIAL);
+ softint_init_isr(sc, "net", PRI_SOFTNET, SOFTINT_NET,
+ IPL_SOFTNET);
+ softint_init_isr(sc, "bio", PRI_SOFTBIO, SOFTINT_BIO,
+ IPL_SOFTBIO);
+ softint_init_isr(sc, "clk", PRI_SOFTCLOCK, SOFTINT_CLOCK,
+ IPL_SOFTCLOCK);
+ softint_init_isr(sc, "ser", PRI_SOFTSERIAL, SOFTINT_SERIAL,
+ IPL_SOFTSERIAL);
if (first != ci) {
mutex_enter(&softint_lock);
@@ -407,15 +414,14 @@ softint_disestablish(void *arg)
softcpu_t *sc;
softhand_t *sh;
uintptr_t offset;
- u_int flags;
offset = (uintptr_t)arg;
KASSERTMSG(offset != 0 && offset < softint_bytes, "%"PRIuPTR" %u",
offset, softint_bytes);
/*
- * Unregister an IPI handler if there is any. Note: there is
- * no need to disable preemption here - ID is stable.
+ * Unregister IPI handler if there is any. Note: there is no need
+ * to disable preemption here - ID is stable.
*/
sc = curcpu()->ci_data.cpu_softcpu;
sh = (softhand_t *)((uint8_t *)sc + offset);
@@ -424,32 +430,11 @@ softint_disestablish(void *arg)
}
/*
- * Run a cross call so we see up to date values of sh_flags from
- * all CPUs. Once softint_disestablish() is called, the caller
- * commits to not trigger the interrupt and set SOFTINT_ACTIVE on
- * it again. So, we are only looking for handler records with
- * SOFTINT_ACTIVE already set.
+ * Run a dummy softint at the same level on all CPUs and wait for
+ * completion, to make sure this softint is no longer running
+ * anywhere.
*/
- if (__predict_true(mp_online)) {
- xc_barrier(0);
- }
-
- for (;;) {
- /* Collect flag values from each CPU. */
- flags = 0;
- for (CPU_INFO_FOREACH(cii, ci)) {
- sc = ci->ci_data.cpu_softcpu;
- sh = (softhand_t *)((uint8_t *)sc + offset);
- KASSERT(sh->sh_func != NULL);
- flags |= sh->sh_flags;
- }
- /* Inactive on all CPUs? */
- if ((flags & SOFTINT_ACTIVE) == 0) {
- break;
- }
- /* Oops, still active. Wait for it to clear. */
- (void)kpause("softdis", false, 1, NULL);
- }
+ xc_barrier(XC_HIGHPRI_IPL(sh->sh_isr->si_ipl));
/* Clear the handler on each CPU. */
mutex_enter(&softint_lock);
@@ -547,8 +532,9 @@ softint_schedule_cpu(void *arg, struct c
* to the level specified, but returns back at splhigh.
*/
static inline void
-softint_execute(softint_t *si, lwp_t *l, int s)
+softint_execute(lwp_t *l, int s)
{
+ softint_t *si = l->l_private;
softhand_t *sh;
KASSERT(si->si_lwp == curlwp);
@@ -571,8 +557,7 @@ softint_execute(softint_t *si, lwp_t *l,
sh = SIMPLEQ_FIRST(&si->si_q);
SIMPLEQ_REMOVE_HEAD(&si->si_q, sh_q);
KASSERT((sh->sh_flags & SOFTINT_PENDING) != 0);
- KASSERT((sh->sh_flags & SOFTINT_ACTIVE) == 0);
- sh->sh_flags ^= (SOFTINT_PENDING | SOFTINT_ACTIVE);
+ sh->sh_flags ^= SOFTINT_PENDING;
splx(s);
/* Run the handler. */
@@ -593,8 +578,6 @@ softint_execute(softint_t *si, lwp_t *l,
__func__, l->l_psrefs, sh->sh_func);
(void)splhigh();
- KASSERT((sh->sh_flags & SOFTINT_ACTIVE) != 0);
- sh->sh_flags ^= SOFTINT_ACTIVE;
}
PSREF_DEBUG_BARRIER();
@@ -717,7 +700,7 @@ softint_thread(void *cookie)
/* Clear pending status and run it. */
s = splhigh();
l->l_cpu->ci_data.cpu_softints &= ~si->si_machdep;
- softint_execute(si, l, s);
+ softint_execute(l, s);
splx(s);
/* Interrupts allowed to run again before switching. */
@@ -786,7 +769,6 @@ void
softint_dispatch(lwp_t *pinned, int s)
{
struct bintime now;
- softint_t *si;
u_int timing;
lwp_t *l;
@@ -808,9 +790,6 @@ softint_dispatch(lwp_t *pinned, int s)
}
#endif
- l = curlwp;
- si = l->l_private;
-
/*
* Note the interrupted LWP, and mark the current LWP as running
* before proceeding. Although this must as a rule be done with
@@ -818,6 +797,7 @@ softint_dispatch(lwp_t *pinned, int s)
* modify the interrupt LWP's state.
*/
timing = softint_timing;
+ l = curlwp;
l->l_switchto = pinned;
l->l_stat = LSONPROC;
@@ -831,7 +811,7 @@ softint_dispatch(lwp_t *pinned, int s)
l->l_pflag |= LP_TIMEINTR;
}
l->l_pflag |= LP_RUNNING;
- softint_execute(si, l, s);
+ softint_execute(l, s);
if (timing) {
binuptime(&now);
updatertime(l, &now);
@@ -840,10 +820,9 @@ softint_dispatch(lwp_t *pinned, int s)
/*
* If we blocked while handling the interrupt, the pinned LWP is
- * gone, so find another LWP to run. It will select a new LWP to
- * run. softint_dispatch() won't be reentered until the priority
- * is finally dropped to IPL_NONE on entry to the LWP chosen by
- * mi_switch().
+ * gone and we are now running as a kthread, so find another LWP to
+ * run. softint_dispatch() won't be reentered until the priority is
+ * finally dropped to IPL_NONE on entry to the next LWP on this CPU.
*/
l->l_stat = LSIDL;
if (l->l_switchto == NULL) {
Index: src/sys/sys/intr.h
diff -u src/sys/sys/intr.h:1.20 src/sys/sys/intr.h:1.21
--- src/sys/sys/intr.h:1.20 Thu Mar 26 20:19:06 2020
+++ src/sys/sys/intr.h Sun May 17 14:11:30 2020
@@ -1,7 +1,7 @@
-/* $NetBSD: intr.h,v 1.20 2020/03/26 20:19:06 ad Exp $ */
+/* $NetBSD: intr.h,v 1.21 2020/05/17 14:11:30 ad Exp $ */
/*-
- * Copyright (c) 2007 The NetBSD Foundation, Inc.
+ * Copyright (c) 2007, 2020 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
@@ -69,7 +69,6 @@ void softint_dispatch(lwp_t *, int);
/* Implementation private flags. */
#define SOFTINT_PENDING 0x1000
-#define SOFTINT_ACTIVE 0x2000
#define SOFTINT_COUNT 0x0004
#define SOFTINT_LVLMASK 0x00ff
