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[src/trunk]: src/sys/kern Gather alldevs into a cacheline-aligned struct.
details: https://anonhg.NetBSD.org/src/rev/2d365e6d0018
branches: trunk
changeset: 822430:2d365e6d0018
user: riastradh <riastradh%NetBSD.org@localhost>
date: Mon Mar 20 01:13:07 2017 +0000
description:
Gather alldevs into a cacheline-aligned struct.
diffstat:
sys/kern/subr_autoconf.c | 152 +++++++++++++++++++++++++---------------------
1 files changed, 81 insertions(+), 71 deletions(-)
diffs (truncated from 390 to 300 lines):
diff -r f56e5b9aed0f -r 2d365e6d0018 sys/kern/subr_autoconf.c
--- a/sys/kern/subr_autoconf.c Mon Mar 20 01:06:29 2017 +0000
+++ b/sys/kern/subr_autoconf.c Mon Mar 20 01:13:07 2017 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: subr_autoconf.c,v 1.250 2017/03/20 01:06:29 riastradh Exp $ */
+/* $NetBSD: subr_autoconf.c,v 1.251 2017/03/20 01:13:07 riastradh Exp $ */
/*
* Copyright (c) 1996, 2000 Christopher G. Demetriou
@@ -77,7 +77,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_autoconf.c,v 1.250 2017/03/20 01:06:29 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_autoconf.c,v 1.251 2017/03/20 01:13:07 riastradh Exp $");
#ifdef _KERNEL_OPT
#include "opt_ddb.h"
@@ -217,12 +217,20 @@
static int config_finalize_done;
/* list of all devices */
-static struct devicelist alldevs = TAILQ_HEAD_INITIALIZER(alldevs);
-static kmutex_t alldevs_mtx;
-static bool alldevs_garbage = false;
-static devgen_t alldevs_gen = 1;
-static int alldevs_nread = 0;
-static int alldevs_nwrite = 0;
+static struct {
+ kmutex_t lock;
+ struct devicelist list;
+ devgen_t gen;
+ int nread;
+ int nwrite;
+ bool garbage;
+} alldevs __cacheline_aligned = {
+ .list = TAILQ_HEAD_INITIALIZER(alldevs.list),
+ .gen = 1,
+ .nread = 0,
+ .nwrite = 0,
+ .garbage = false,
+};
static int config_pending; /* semaphore for mountroot */
static kmutex_t config_misc_lock;
@@ -341,7 +349,7 @@
KASSERT(config_initialized == false);
- mutex_init(&alldevs_mtx, MUTEX_DEFAULT, IPL_VM);
+ mutex_init(&alldevs.lock, MUTEX_DEFAULT, IPL_VM);
mutex_init(&config_misc_lock, MUTEX_DEFAULT, IPL_NONE);
cv_init(&config_misc_cv, "cfgmisc");
@@ -1155,9 +1163,9 @@
/*
* Expand the size of the cd_devs array if necessary.
*
- * The caller must hold alldevs_mtx. config_makeroom() may release and
- * re-acquire alldevs_mtx, so callers should re-check conditions such
- * as alldevs_nwrite == 0 and alldevs_nread == 0 when config_makeroom()
+ * The caller must hold alldevs.lock. config_makeroom() may release and
+ * re-acquire alldevs.lock, so callers should re-check conditions such
+ * as alldevs.nwrite == 0 and alldevs.nread == 0 when config_makeroom()
* returns.
*/
static void
@@ -1166,8 +1174,8 @@
int ondevs, nndevs;
device_t *osp, *nsp;
- KASSERT(mutex_owned(&alldevs_mtx));
- alldevs_nwrite++;
+ KASSERT(mutex_owned(&alldevs.lock));
+ alldevs.nwrite++;
for (nndevs = MAX(4, cd->cd_ndevs); nndevs <= n; nndevs += nndevs)
;
@@ -1179,22 +1187,24 @@
ondevs = cd->cd_ndevs;
osp = cd->cd_devs;
- /* Release alldevs_mtx around allocation, which may
+ /*
+ * Release alldevs.lock around allocation, which may
* sleep.
*/
- mutex_exit(&alldevs_mtx);
+ mutex_exit(&alldevs.lock);
nsp = kmem_alloc(sizeof(device_t[nndevs]), KM_SLEEP);
if (nsp == NULL)
panic("%s: could not expand cd_devs", __func__);
- mutex_enter(&alldevs_mtx);
-
- /* If another thread moved the array while we did
- * not hold alldevs_mtx, try again.
+ mutex_enter(&alldevs.lock);
+
+ /*
+ * If another thread moved the array while we did
+ * not hold alldevs.lock, try again.
*/
if (cd->cd_devs != osp) {
- mutex_exit(&alldevs_mtx);
+ mutex_exit(&alldevs.lock);
kmem_free(nsp, sizeof(device_t[nndevs]));
- mutex_enter(&alldevs_mtx);
+ mutex_enter(&alldevs.lock);
continue;
}
@@ -1205,13 +1215,13 @@
cd->cd_ndevs = nndevs;
cd->cd_devs = nsp;
if (ondevs != 0) {
- mutex_exit(&alldevs_mtx);
+ mutex_exit(&alldevs.lock);
kmem_free(osp, sizeof(device_t[ondevs]));
- mutex_enter(&alldevs_mtx);
+ mutex_enter(&alldevs.lock);
}
}
- KASSERT(mutex_owned(&alldevs_mtx));
- alldevs_nwrite--;
+ KASSERT(mutex_owned(&alldevs.lock));
+ alldevs.nwrite--;
}
/*
@@ -1221,16 +1231,16 @@
config_devlink(device_t dev)
{
- mutex_enter(&alldevs_mtx);
+ mutex_enter(&alldevs.lock);
KASSERT(device_cfdriver(dev)->cd_devs[dev->dv_unit] == dev);
- dev->dv_add_gen = alldevs_gen;
+ dev->dv_add_gen = alldevs.gen;
/* It is safe to add a device to the tail of the list while
* readers and writers are in the list.
*/
- TAILQ_INSERT_TAIL(&alldevs, dev, dv_list);
- mutex_exit(&alldevs_mtx);
+ TAILQ_INSERT_TAIL(&alldevs.list, dev, dv_list);
+ mutex_exit(&alldevs.lock);
}
static void
@@ -1245,7 +1255,7 @@
}
/*
- * Caller must hold alldevs_mtx.
+ * Caller must hold alldevs.lock.
*/
static void
config_devunlink(device_t dev, struct devicelist *garbage)
@@ -1254,10 +1264,10 @@
cfdriver_t cd = device_cfdriver(dev);
int i;
- KASSERT(mutex_owned(&alldevs_mtx));
+ KASSERT(mutex_owned(&alldevs.lock));
/* Unlink from device list. Link to garbage list. */
- TAILQ_REMOVE(&alldevs, dev, dv_list);
+ TAILQ_REMOVE(&alldevs.list, dev, dv_list);
TAILQ_INSERT_TAIL(garbage, dev, dv_list);
/* Remove from cfdriver's array. */
@@ -1660,7 +1670,7 @@
}
/*
- * Caller must hold alldevs_mtx.
+ * Caller must hold alldevs.lock.
*/
static void
config_collect_garbage(struct devicelist *garbage)
@@ -1669,20 +1679,20 @@
KASSERT(!cpu_intr_p());
KASSERT(!cpu_softintr_p());
- KASSERT(mutex_owned(&alldevs_mtx));
-
- while (alldevs_nwrite == 0 && alldevs_nread == 0 && alldevs_garbage) {
- TAILQ_FOREACH(dv, &alldevs, dv_list) {
+ KASSERT(mutex_owned(&alldevs.lock));
+
+ while (alldevs.nwrite == 0 && alldevs.nread == 0 && alldevs.garbage) {
+ TAILQ_FOREACH(dv, &alldevs.list, dv_list) {
if (dv->dv_del_gen != 0)
break;
}
if (dv == NULL) {
- alldevs_garbage = false;
+ alldevs.garbage = false;
break;
}
config_devunlink(dv, garbage);
}
- KASSERT(mutex_owned(&alldevs_mtx));
+ KASSERT(mutex_owned(&alldevs.lock));
}
static void
@@ -1731,17 +1741,17 @@
ca = dev->dv_cfattach;
KASSERT(ca != NULL);
- mutex_enter(&alldevs_mtx);
+ mutex_enter(&alldevs.lock);
if (dev->dv_del_gen != 0) {
- mutex_exit(&alldevs_mtx);
+ mutex_exit(&alldevs.lock);
#ifdef DIAGNOSTIC
printf("%s: %s is already detached\n", __func__,
device_xname(dev));
#endif /* DIAGNOSTIC */
return ENOENT;
}
- alldevs_nwrite++;
- mutex_exit(&alldevs_mtx);
+ alldevs.nwrite++;
+ mutex_exit(&alldevs.lock);
if (!detachall &&
(flags & (DETACH_SHUTDOWN|DETACH_FORCE)) == DETACH_SHUTDOWN &&
@@ -1818,14 +1828,14 @@
out:
config_alldevs_enter(&af);
- KASSERT(alldevs_nwrite != 0);
- --alldevs_nwrite;
+ KASSERT(alldevs.nwrite != 0);
+ --alldevs.nwrite;
if (rv == 0 && dev->dv_del_gen == 0) {
- if (alldevs_nwrite == 0 && alldevs_nread == 0)
+ if (alldevs.nwrite == 0 && alldevs.nread == 0)
config_devunlink(dev, &af.af_garbage);
else {
- dev->dv_del_gen = alldevs_gen;
- alldevs_garbage = true;
+ dev->dv_del_gen = alldevs.gen;
+ alldevs.garbage = true;
}
}
config_alldevs_exit(&af);
@@ -2215,14 +2225,14 @@
config_alldevs_enter(struct alldevs_foray *af)
{
TAILQ_INIT(&af->af_garbage);
- mutex_enter(&alldevs_mtx);
+ mutex_enter(&alldevs.lock);
config_collect_garbage(&af->af_garbage);
}
static void
config_alldevs_exit(struct alldevs_foray *af)
{
- mutex_exit(&alldevs_mtx);
+ mutex_exit(&alldevs.lock);
config_dump_garbage(&af->af_garbage);
}
@@ -2236,12 +2246,12 @@
{
device_t dv;
- mutex_enter(&alldevs_mtx);
+ mutex_enter(&alldevs.lock);
if (unit < 0 || unit >= cd->cd_ndevs)
dv = NULL;
else if ((dv = cd->cd_devs[unit]) != NULL && dv->dv_del_gen != 0)
dv = NULL;
- mutex_exit(&alldevs_mtx);
+ mutex_exit(&alldevs.lock);
return dv;
}
@@ -2786,24 +2796,24 @@
if ((flags & DEVITER_F_SHUTDOWN) != 0)
flags |= DEVITER_F_RW;
- mutex_enter(&alldevs_mtx);
+ mutex_enter(&alldevs.lock);
if ((flags & DEVITER_F_RW) != 0)
- alldevs_nwrite++;
+ alldevs.nwrite++;
else
- alldevs_nread++;
- di->di_gen = alldevs_gen++;
+ alldevs.nread++;
+ di->di_gen = alldevs.gen++;
di->di_flags = flags;
switch (di->di_flags & (DEVITER_F_LEAVES_FIRST|DEVITER_F_ROOT_FIRST)) {
case DEVITER_F_LEAVES_FIRST:
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