svn commit: r356325 - head/sys/kern
Kyle Evans
kevans at FreeBSD.org
Fri Jan 3 18:29:21 UTC 2020
Author: kevans
Date: Fri Jan 3 18:29:20 2020
New Revision: 356325
URL: https://svnweb.freebsd.org/changeset/base/356325
Log:
emulated atomic64: disable interrupts as the lock mechanism on !SMP
Reviewed by: jhibbits, bdragon
Differential Revision: https://reviews.freebsd.org/D23015
Modified:
head/sys/kern/subr_atomic64.c
Modified: head/sys/kern/subr_atomic64.c
==============================================================================
--- head/sys/kern/subr_atomic64.c Fri Jan 3 18:21:00 2020 (r356324)
+++ head/sys/kern/subr_atomic64.c Fri Jan 3 18:29:20 2020 (r356325)
@@ -55,9 +55,12 @@ enum {
};
#ifdef _KERNEL
+#ifdef SMP
+
#define A64_POOL_SIZE MAXCPU
/* Estimated size of a cacheline */
#define CACHE_ALIGN CACHE_LINE_SIZE
+static struct mtx a64_mtx_pool[A64_POOL_SIZE];
#define GET_MUTEX(p) \
(&a64_mtx_pool[(pmap_kextract((vm_offset_t)p) / CACHE_ALIGN) % (A64_POOL_SIZE)])
@@ -68,6 +71,13 @@ enum {
#define UNLOCK_A64() if (smp_started) mtx_unlock(_amtx)
+#else /* !SMP */
+
+#define LOCK_A64() { register_t s = intr_disable()
+#define UNLOCK_A64() intr_restore(s); }
+
+#endif /* SMP */
+
#define ATOMIC64_EMU_UN(op, rt, block, ret) \
rt \
atomic_##op##_64(volatile u_int64_t *p) { \
@@ -86,8 +96,6 @@ enum {
UNLOCK_A64(); \
ret; } struct hack
-static struct mtx a64_mtx_pool[A64_POOL_SIZE];
-
ATOMIC64_EMU_BIN(add, void, (*p = *p + v), return);
ATOMIC64_EMU_BIN(clear, void, *p &= ~v, return);
ATOMIC64_EMU_BIN(fetchadd, u_int64_t, (*p = *p + v, v = *p - v), return (v));
@@ -126,6 +134,7 @@ int atomic_fcmpset_64(volatile u_int64_t *p, u_int64_t
return (tmp == tmp_old);
}
+#ifdef SMP
static void
atomic64_mtxinit(void *x __unused)
{
@@ -136,5 +145,6 @@ atomic64_mtxinit(void *x __unused)
}
SYSINIT(atomic64_mtxinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, atomic64_mtxinit, NULL);
+#endif /* SMP */
#endif /* _KERNEL */
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