Module Name: src
Committed By: riastradh
Date: Fri Nov 27 20:10:25 UTC 2020
Modified Files:
src/sys/dev/tprof: tprof.c
Log Message:
tprof: Use percpu rather than a MAXCPUS-element array.
To generate a diff of this commit:
cvs rdiff -u -r1.14 -r1.15 src/sys/dev/tprof/tprof.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/dev/tprof/tprof.c
diff -u src/sys/dev/tprof/tprof.c:1.14 src/sys/dev/tprof/tprof.c:1.15
--- src/sys/dev/tprof/tprof.c:1.14 Fri Jul 13 07:56:29 2018
+++ src/sys/dev/tprof/tprof.c Fri Nov 27 20:10:25 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: tprof.c,v 1.14 2018/07/13 07:56:29 maxv Exp $ */
+/* $NetBSD: tprof.c,v 1.15 2020/11/27 20:10:25 riastradh Exp $ */
/*-
* Copyright (c)2008,2009,2010 YAMAMOTO Takashi,
@@ -27,20 +27,21 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: tprof.c,v 1.14 2018/07/13 07:56:29 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: tprof.c,v 1.15 2020/11/27 20:10:25 riastradh Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
-#include <sys/cpu.h>
-#include <sys/conf.h>
#include <sys/callout.h>
+#include <sys/conf.h>
+#include <sys/cpu.h>
#include <sys/kmem.h>
#include <sys/module.h>
+#include <sys/percpu.h>
#include <sys/proc.h>
-#include <sys/workqueue.h>
#include <sys/queue.h>
+#include <sys/workqueue.h>
#include <dev/tprof/tprof.h>
#include <dev/tprof/tprof_ioctl.h>
@@ -97,7 +98,7 @@ static lwp_t *tprof_owner;
static STAILQ_HEAD(, tprof_buf) tprof_list; /* L: global buffer list */
static u_int tprof_nbuf_on_list; /* L: # of buffers on tprof_list */
static struct workqueue *tprof_wq;
-static tprof_cpu_t tprof_cpus[MAXCPUS] __aligned(CACHE_LINE_SIZE);
+static struct percpu *tprof_cpus __read_mostly; /* tprof_cpu_t * */
static u_int tprof_samples_per_buf;
static tprof_backend_t *tprof_backend; /* S: */
@@ -116,8 +117,20 @@ static struct tprof_stat tprof_stat; /*
static tprof_cpu_t *
tprof_cpu(struct cpu_info *ci)
{
+ tprof_cpu_t **cp, *c;
- return &tprof_cpus[cpu_index(ci)];
+ /*
+ * As long as xcalls are blocked -- e.g., by kpreempt_disable
+ * -- the percpu object will not be swapped and destroyed. We
+ * can't write to it, because the data may have already been
+ * moved to a new buffer, but we can safely read from it.
+ */
+ kpreempt_disable();
+ cp = percpu_getptr_remote(tprof_cpus, ci);
+ c = *cp;
+ kpreempt_enable();
+
+ return c;
}
static tprof_cpu_t *
@@ -132,7 +145,7 @@ tprof_buf_alloc(void)
{
tprof_buf_t *new;
u_int size = tprof_samples_per_buf;
-
+
new = kmem_alloc(TPROF_BUF_BYTESIZE(size), KM_SLEEP);
new->b_used = 0;
new->b_size = size;
@@ -682,9 +695,31 @@ tprofattach(int nunits)
MODULE(MODULE_CLASS_DRIVER, tprof, NULL);
static void
+tprof_cpu_init(void *vcp, void *vcookie, struct cpu_info *ci)
+{
+ tprof_cpu_t **cp = vcp, *c;
+
+ c = kmem_zalloc(sizeof(*c), KM_SLEEP);
+ c->c_buf = NULL;
+ c->c_cpuid = cpu_index(ci);
+ *cp = c;
+}
+
+static void
+tprof_cpu_fini(void *vcp, void *vcookie, struct cpu_info *ci)
+{
+ tprof_cpu_t **cp = vcp, *c;
+
+ c = *cp;
+ KASSERT(c->c_cpuid == cpu_index(ci));
+ KASSERT(c->c_buf == NULL);
+ kmem_free(c, sizeof(*c));
+ *cp = NULL;
+}
+
+static void
tprof_driver_init(void)
{
- unsigned int i;
mutex_init(&tprof_lock, MUTEX_DEFAULT, IPL_NONE);
mutex_init(&tprof_reader_lock, MUTEX_DEFAULT, IPL_NONE);
@@ -692,18 +727,15 @@ tprof_driver_init(void)
cv_init(&tprof_cv, "tprof");
cv_init(&tprof_reader_cv, "tprof_rd");
STAILQ_INIT(&tprof_list);
- for (i = 0; i < __arraycount(tprof_cpus); i++) {
- tprof_cpu_t * const c = &tprof_cpus[i];
-
- c->c_buf = NULL;
- c->c_cpuid = i;
- }
+ tprof_cpus = percpu_create(sizeof(tprof_cpu_t *),
+ tprof_cpu_init, tprof_cpu_fini, NULL);
}
static void
tprof_driver_fini(void)
{
+ percpu_free(tprof_cpus, sizeof(tprof_cpu_t *));
mutex_destroy(&tprof_lock);
mutex_destroy(&tprof_reader_lock);
mutex_destroy(&tprof_startstop_lock);
