diff options
Diffstat (limited to 'sys/vm/vm_kern.c')
| -rw-r--r-- | sys/vm/vm_kern.c | 78 |
1 files changed, 54 insertions, 24 deletions
diff --git a/sys/vm/vm_kern.c b/sys/vm/vm_kern.c index ea7f45b64832..b2e11021815f 100644 --- a/sys/vm/vm_kern.c +++ b/sys/vm/vm_kern.c @@ -61,7 +61,7 @@ * any improvements or extensions that they make and grant Carnegie the * rights to redistribute these changes. * - * $Id: vm_kern.c,v 1.49 1998/08/24 08:39:37 dfr Exp $ + * $Id: vm_kern.c,v 1.50 1998/09/04 08:06:57 dfr Exp $ */ /* @@ -181,8 +181,9 @@ kmem_alloc(map, size) VM_ALLOC_ZERO | VM_ALLOC_RETRY); if ((mem->flags & PG_ZERO) == 0) vm_page_zero_fill(mem); - vm_page_flag_clear(mem, (PG_BUSY | PG_ZERO)); mem->valid = VM_PAGE_BITS_ALL; + vm_page_flag_clear(mem, PG_ZERO); + vm_page_wakeup(mem); } /* @@ -200,6 +201,8 @@ kmem_alloc(map, size) * Release a region of kernel virtual memory allocated * with kmem_alloc, and return the physical pages * associated with that region. + * + * This routine may not block on kernel maps. */ void kmem_free(map, addr, size) @@ -252,26 +255,31 @@ kmem_suballoc(parent, min, max, size) } /* - * Allocate wired-down memory in the kernel's address map for the higher - * level kernel memory allocator (kern/kern_malloc.c). We cannot use - * kmem_alloc() because we may need to allocate memory at interrupt - * level where we cannot block (canwait == FALSE). + * kmem_malloc: + * + * Allocate wired-down memory in the kernel's address map for the higher + * level kernel memory allocator (kern/kern_malloc.c). We cannot use + * kmem_alloc() because we may need to allocate memory at interrupt + * level where we cannot block (canwait == FALSE). + * + * This routine has its own private kernel submap (kmem_map) and object + * (kmem_object). This, combined with the fact that only malloc uses + * this routine, ensures that we will never block in map or object waits. * - * This routine has its own private kernel submap (kmem_map) and object - * (kmem_object). This, combined with the fact that only malloc uses - * this routine, ensures that we will never block in map or object waits. + * Note that this still only works in a uni-processor environment and + * when called at splhigh(). * - * Note that this still only works in a uni-processor environment and - * when called at splhigh(). + * We don't worry about expanding the map (adding entries) since entries + * for wired maps are statically allocated. * - * We don't worry about expanding the map (adding entries) since entries - * for wired maps are statically allocated. + * NOTE: This routine is not supposed to block if M_NOWAIT is set, but + * I have not verified that it actually does not block. */ vm_offset_t -kmem_malloc(map, size, waitflag) +kmem_malloc(map, size, flags) register vm_map_t map; register vm_size_t size; - boolean_t waitflag; + int flags; { register vm_offset_t offset, i; vm_map_entry_t entry; @@ -297,7 +305,7 @@ kmem_malloc(map, size, waitflag) printf("Out of mbuf clusters - adjust NMBCLUSTERS or increase maxusers!\n"); return (0); } - if (waitflag == M_WAITOK) + if ((flags & M_NOWAIT) == 0) panic("kmem_malloc(%d): kmem_map too small: %d total allocated", size, map->size); return (0); @@ -308,9 +316,19 @@ kmem_malloc(map, size, waitflag) VM_PROT_ALL, VM_PROT_ALL, 0); for (i = 0; i < size; i += PAGE_SIZE) { + /* + * Note: if M_NOWAIT specified alone, allocate from + * interrupt-safe queues only (just the free list). If + * M_ASLEEP or M_USE_RESERVE is also specified, we can also + * allocate from the cache. Neither of the latter two + * flags may be specified from an interrupt since interrupts + * are not allowed to mess with the cache queue. + */ retry: m = vm_page_alloc(kmem_object, OFF_TO_IDX(offset + i), - (waitflag == M_NOWAIT) ? VM_ALLOC_INTERRUPT : VM_ALLOC_SYSTEM); + ((flags & (M_NOWAIT|M_ASLEEP|M_USE_RESERVE)) == M_NOWAIT) ? + VM_ALLOC_INTERRUPT : + VM_ALLOC_SYSTEM); /* * Ran out of space, free everything up and return. Don't need @@ -318,7 +336,7 @@ retry: * aren't on any queues. */ if (m == NULL) { - if (waitflag == M_WAITOK) { + if ((flags & M_NOWAIT) == 0) { VM_WAIT; goto retry; } @@ -330,6 +348,9 @@ retry: } vm_map_delete(map, addr, addr + size); vm_map_unlock(map); + if (flags & M_ASLEEP) { + VM_AWAIT; + } return (0); } vm_page_flag_clear(m, PG_ZERO); @@ -359,6 +380,9 @@ retry: m = vm_page_lookup(kmem_object, OFF_TO_IDX(offset + i)); vm_page_wire(m); vm_page_wakeup(m); + /* + * Because this is kernel_pmap, this call will not block. + */ pmap_enter(kernel_pmap, addr + i, VM_PAGE_TO_PHYS(m), VM_PROT_ALL, 1); vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE | PG_REFERENCED); @@ -369,12 +393,14 @@ retry: } /* - * kmem_alloc_wait + * kmem_alloc_wait: * * Allocates pageable memory from a sub-map of the kernel. If the submap * has no room, the caller sleeps waiting for more memory in the submap. * + * This routine may block. */ + vm_offset_t kmem_alloc_wait(map, size) vm_map_t map; @@ -406,7 +432,7 @@ kmem_alloc_wait(map, size) } /* - * kmem_free_wakeup + * kmem_free_wakeup: * * Returns memory to a submap of the kernel, and wakes up any processes * waiting for memory in that map. @@ -424,11 +450,14 @@ kmem_free_wakeup(map, addr, size) } /* - * Create the kernel map; insert a mapping covering kernel text, data, bss, - * and all space allocated thus far (`boostrap' data). The new map will thus - * map the range between VM_MIN_KERNEL_ADDRESS and `start' as allocated, and - * the range between `start' and `end' as free. + * kmem_init: + * + * Create the kernel map; insert a mapping covering kernel text, + * data, bss, and all space allocated thus far (`boostrap' data). The + * new map will thus map the range between VM_MIN_KERNEL_ADDRESS and + * `start' as allocated, and the range between `start' and `end' as free. */ + void kmem_init(start, end) vm_offset_t start, end; @@ -445,3 +474,4 @@ kmem_init(start, end) /* ... and ending with the completion of the above `insert' */ vm_map_unlock(m); } + |