Module Name: src
Committed By: ad
Date: Mon Dec 16 19:22:15 UTC 2019
Modified Files:
src/sys/kern: kern_turnstile.c
Log Message:
Just make the turnstile locks statics and avoid the indirect reference
since COHERENCY_UNIT does the right thing in !MP.
To generate a diff of this commit:
cvs rdiff -u -r1.34 -r1.35 src/sys/kern/kern_turnstile.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/kern/kern_turnstile.c
diff -u src/sys/kern/kern_turnstile.c:1.34 src/sys/kern/kern_turnstile.c:1.35
--- src/sys/kern/kern_turnstile.c:1.34 Sun Nov 24 13:14:23 2019
+++ src/sys/kern/kern_turnstile.c Mon Dec 16 19:22:15 2019
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_turnstile.c,v 1.34 2019/11/24 13:14:23 ad Exp $ */
+/* $NetBSD: kern_turnstile.c,v 1.35 2019/12/16 19:22:15 ad Exp $ */
/*-
* Copyright (c) 2002, 2006, 2007, 2009, 2019 The NetBSD Foundation, Inc.
@@ -60,7 +60,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_turnstile.c,v 1.34 2019/11/24 13:14:23 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_turnstile.c,v 1.35 2019/12/16 19:22:15 ad Exp $");
#include <sys/param.h>
#include <sys/lockdebug.h>
@@ -78,12 +78,15 @@ __KERNEL_RCSID(0, "$NetBSD: kern_turnsti
#define TS_HASH_MASK (TS_HASH_SIZE - 1)
#define TS_HASH(obj) (((uintptr_t)(obj) >> 6) & TS_HASH_MASK)
-/* Keep the chains and mutex pointers apart to prevent false sharing. */
static tschain_t turnstile_chains[TS_HASH_SIZE] __cacheline_aligned;
-static kmutex_t *turnstile_locks[TS_HASH_SIZE] __read_mostly;
pool_cache_t turnstile_cache __read_mostly;
extern turnstile_t turnstile0;
+static union {
+ kmutex_t lock;
+ uint8_t pad[COHERENCY_UNIT];
+} turnstile_locks[TS_HASH_SIZE] __cacheline_aligned;
+
static int turnstile_ctor(void *, void *, int);
/*
@@ -98,7 +101,7 @@ turnstile_init(void)
for (i = 0; i < TS_HASH_SIZE; i++) {
LIST_INIT(&turnstile_chains[i]);
- turnstile_locks[i] = mutex_obj_alloc(MUTEX_DEFAULT, IPL_SCHED);
+ mutex_init(&turnstile_locks[i].lock, MUTEX_DEFAULT, IPL_SCHED);
}
turnstile_cache = pool_cache_init(sizeof(turnstile_t), coherency_unit,
@@ -173,7 +176,7 @@ turnstile_lookup(wchan_t obj)
hash = TS_HASH(obj);
tc = &turnstile_chains[hash];
- mutex_spin_enter(turnstile_locks[hash]);
+ mutex_spin_enter(&turnstile_locks[hash].lock);
LIST_FOREACH(ts, tc, ts_chain)
if (ts->ts_obj == obj)
@@ -195,7 +198,7 @@ void
turnstile_exit(wchan_t obj)
{
- mutex_spin_exit(turnstile_locks[TS_HASH(obj)]);
+ mutex_spin_exit(&turnstile_locks[TS_HASH(obj)].lock);
}
/*
@@ -381,7 +384,7 @@ turnstile_block(turnstile_t *ts, int q,
hash = TS_HASH(obj);
tc = &turnstile_chains[hash];
- lock = turnstile_locks[hash];
+ lock = &turnstile_locks[hash].lock;
KASSERT(q == TS_READER_Q || q == TS_WRITER_Q);
KASSERT(mutex_owned(lock));
@@ -455,7 +458,7 @@ turnstile_wakeup(turnstile_t *ts, int q,
lwp_t *l;
hash = TS_HASH(ts->ts_obj);
- lock = turnstile_locks[hash];
+ lock = &turnstile_locks[hash].lock;
sq = &ts->ts_sleepq[q];
KASSERT(q == TS_READER_Q || q == TS_WRITER_Q);
@@ -539,7 +542,7 @@ turnstile_print(volatile void *obj, void
hash = TS_HASH(obj);
tc = &turnstile_chains[hash];
- lock = turnstile_locks[hash];
+ lock = &turnstile_locks[hash].lock;
LIST_FOREACH(ts, tc, ts_chain)
if (ts->ts_obj == obj)
