The branch stable/13 has been updated by mhorne:
URL:
https://cgit.FreeBSD.org/src/commit/?id=ae6e42b59e6831c8a74620c99120d089a25efa84
commit ae6e42b59e6831c8a74620c99120d089a25efa84
Author: Mitchell Horne <mho...@freebsd.org>
AuthorDate: 2023-02-14 18:02:12 +0000
Commit: Mitchell Horne <mho...@freebsd.org>
CommitDate: 2023-03-17 19:55:45 +0000
intrng: track counter allocation with a bitmap
Crucially, this allows releasing counters, and interrupt sources by
extension. Where before we were incrementing intrcnt_index with atomics,
now we protect the bitmap using the existing isrc_table_lock mutex.
Reviewed by: mmel
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D38437
(cherry picked from commit 28137bdb19aa34b8351108de4257795a93c0ba09)
---
sys/kern/subr_intr.c | 54 ++++++++++++++++++++++++++++++++++++++--------------
1 file changed, 40 insertions(+), 14 deletions(-)
diff --git a/sys/kern/subr_intr.c b/sys/kern/subr_intr.c
index 078f8e544f10..f44291887e8c 100644
--- a/sys/kern/subr_intr.c
+++ b/sys/kern/subr_intr.c
@@ -42,6 +42,7 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
+#include <sys/bitstring.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/cpuset.h>
@@ -152,7 +153,8 @@ u_long *intrcnt;
char *intrnames;
size_t sintrcnt;
size_t sintrnames;
-static u_int intrcnt_index;
+int nintrcnt;
+static bitstr_t *intrcnt_bitmap;
static struct intr_irqsrc *intr_map_get_isrc(u_int res_id);
static void intr_map_set_isrc(u_int res_id, struct intr_irqsrc *isrc);
@@ -166,7 +168,6 @@ static void intr_map_copy_map_data(u_int res_id, device_t
*dev, intptr_t *xref,
static void
intr_irq_init(void *dummy __unused)
{
- u_int intrcnt_count;
SLIST_INIT(&pic_list);
mtx_init(&pic_list_lock, "intr pic list", NULL, MTX_DEF);
@@ -177,17 +178,21 @@ intr_irq_init(void *dummy __unused)
* - 2 counters for each I/O interrupt.
* - MAXCPU counters for each IPI counters for SMP.
*/
- intrcnt_count = intr_nirq * 2;
+ nintrcnt = intr_nirq * 2;
#ifdef SMP
- intrcnt_count += INTR_IPI_COUNT * MAXCPU;
+ nintrcnt += INTR_IPI_COUNT * MAXCPU;
#endif
- intrcnt = mallocarray(intrcnt_count, sizeof(u_long), M_INTRNG,
+ intrcnt = mallocarray(nintrcnt, sizeof(u_long), M_INTRNG,
M_WAITOK | M_ZERO);
- intrnames = mallocarray(intrcnt_count, INTRNAME_LEN, M_INTRNG,
+ intrnames = mallocarray(nintrcnt, INTRNAME_LEN, M_INTRNG,
M_WAITOK | M_ZERO);
- sintrcnt = intrcnt_count * sizeof(u_long);
- sintrnames = intrcnt_count * INTRNAME_LEN;
+ sintrcnt = nintrcnt * sizeof(u_long);
+ sintrnames = nintrcnt * INTRNAME_LEN;
+
+ /* Allocate the bitmap tracking counter allocations. */
+ intrcnt_bitmap = bit_alloc(nintrcnt, M_INTRNG, M_WAITOK | M_ZERO);
+
irq_sources = mallocarray(intr_nirq, sizeof(struct intr_irqsrc*),
M_INTRNG, M_WAITOK | M_ZERO);
}
@@ -266,13 +271,17 @@ isrc_update_name(struct intr_irqsrc *isrc, const char
*name)
static void
isrc_setup_counters(struct intr_irqsrc *isrc)
{
- u_int index;
+ int index;
+
+ mtx_assert(&isrc_table_lock, MA_OWNED);
/*
- * XXX - it does not work well with removable controllers and
- * interrupt sources !!!
+ * Allocate two counter values, the second tracking "stray" interrupts.
*/
- index = atomic_fetchadd_int(&intrcnt_index, 2);
+ bit_ffc_area(intrcnt_bitmap, nintrcnt, 2, &index);
+ if (index == -1)
+ panic("Failed to allocate 2 counters. Array exhausted?");
+ bit_nset(intrcnt_bitmap, index, index + 1);
isrc->isrc_index = index;
isrc->isrc_count = &intrcnt[index];
isrc_update_name(isrc, NULL);
@@ -284,8 +293,11 @@ isrc_setup_counters(struct intr_irqsrc *isrc)
static void
isrc_release_counters(struct intr_irqsrc *isrc)
{
+ int idx = isrc->isrc_index;
- panic("%s: not implemented", __func__);
+ mtx_assert(&isrc_table_lock, MA_OWNED);
+
+ bit_nclear(intrcnt_bitmap, idx, idx + 1);
}
#ifdef SMP
@@ -298,11 +310,25 @@ intr_ipi_setup_counters(const char *name)
u_int index, i;
char str[INTRNAME_LEN];
- index = atomic_fetchadd_int(&intrcnt_index, MAXCPU);
+ mtx_lock(&isrc_table_lock);
+
+ /*
+ * We should never have a problem finding MAXCPU contiguous counters,
+ * in practice. Interrupts will be allocated sequentially during boot,
+ * so the array should fill from low to high index. Once reserved, the
+ * IPI counters will never be released. Similarly, we will not need to
+ * allocate more IPIs once the system is running.
+ */
+ bit_ffc_area(intrcnt_bitmap, nintrcnt, MAXCPU, &index);
+ if (index == -1)
+ panic("Failed to allocate %d counters. Array exhausted?",
+ MAXCPU);
+ bit_nset(intrcnt_bitmap, index, index + MAXCPU - 1);
for (i = 0; i < MAXCPU; i++) {
snprintf(str, INTRNAME_LEN, "cpu%d:%s", i, name);
intrcnt_setname(str, index + i);
}
+ mtx_unlock(&isrc_table_lock);
return (&intrcnt[index]);
}
#endif
