diff options
Diffstat (limited to 'usr/src/uts/common/sys/kmem_impl.h')
| -rw-r--r-- | usr/src/uts/common/sys/kmem_impl.h | 31 |
1 files changed, 26 insertions, 5 deletions
diff --git a/usr/src/uts/common/sys/kmem_impl.h b/usr/src/uts/common/sys/kmem_impl.h index 96b88261b7..3b780f843e 100644 --- a/usr/src/uts/common/sys/kmem_impl.h +++ b/usr/src/uts/common/sys/kmem_impl.h @@ -20,15 +20,13 @@ */ /* - * Copyright 2008 Sun Microsystems, Inc. All rights reserved. + * Copyright 2009 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ #ifndef _SYS_KMEM_IMPL_H #define _SYS_KMEM_IMPL_H -#pragma ident "%Z%%M% %I% %E% SMI" - #include <sys/kmem.h> #include <sys/vmem.h> #include <sys/thread.h> @@ -172,8 +170,26 @@ typedef struct kmem_buftag_lite { #define KMEM_SLAB(cp, buf) \ ((kmem_slab_t *)P2END((uintptr_t)(buf), (cp)->cache_slabsize) - 1) -#define KMEM_CPU_CACHE(cp) \ - (kmem_cpu_cache_t *)((char *)cp + CPU->cpu_cache_offset) +/* + * The "CPU" macro loads a cpu_t that refers to the cpu that the current + * thread is running on at the time the macro is executed. A context switch + * may occur immediately after loading this data structure, leaving this + * thread pointing at the cpu_t for the previous cpu. This is not a problem; + * we'd just end up checking the previous cpu's per-cpu cache, and then check + * the other layers of the kmem cache if need be. + * + * It's not even a problem if the old cpu gets DR'ed out during the context + * switch. The cpu-remove DR operation bzero()s the cpu_t, but doesn't free + * it. So the cpu_t's cpu_cache_offset would read as 0, causing us to use + * cpu 0's per-cpu cache. + * + * So, there is no need to disable kernel preemption while using the CPU macro + * below since if we have been context switched, there will not be any + * correctness problem, just a momentary use of a different per-cpu cache. + */ + +#define KMEM_CPU_CACHE(cp) \ + (kmem_cpu_cache_t *)((char *)(&cp->cache_cpu) + CPU->cpu_cache_offset) #define KMEM_MAGAZINE_VALID(cp, mp) \ (((kmem_slab_t *)P2END((uintptr_t)(mp), PAGESIZE) - 1)->slab_cache == \ @@ -235,6 +251,11 @@ typedef struct kmem_magtype { #define KMEM_CACHE_SIZE(ncpus) \ ((size_t)(&((kmem_cache_t *)0)->cache_cpu[ncpus])) +/* Offset from kmem_cache->cache_cpu for per cpu caches */ +#define KMEM_CPU_CACHE_OFFSET(cpuid) \ + ((size_t)(&((kmem_cache_t *)0)->cache_cpu[cpuid]) - \ + (size_t)(&((kmem_cache_t *)0)->cache_cpu)) + typedef struct kmem_cpu_cache { kmutex_t cc_lock; /* protects this cpu's local cache */ uint64_t cc_alloc; /* allocations from this cpu */ |