diff options
Diffstat (limited to 'hurd')
| -rw-r--r-- | hurd/hurdmalloc.c | 163 |
1 files changed, 122 insertions, 41 deletions
diff --git a/hurd/hurdmalloc.c b/hurd/hurdmalloc.c index 1de887bb80..5f719df9c6 100644 --- a/hurd/hurdmalloc.c +++ b/hurd/hurdmalloc.c @@ -37,24 +37,39 @@ /* * HISTORY * $Log$ - * Revision 1.10 1995/02/13 22:04:34 roland - * (malloc_init): Add self reference to avoid not only the `defined but not - * used' warning, but also to avoid GCC optimizing out the entire function - * (!). + * Revision 1.11 1996/06/06 15:13:47 miles + * Changes to bring in line with the hurd libthreads/malloc.c: + * (more_memory): Use assert_perror instead of MACH_CALL. + * "cthread_internals.h": Include removed. + * (realloc): Use LOG2_MIN_SIZE. + * (LOG2_MIN_SIZE): New macro. + * (realloc): Don't bother allocating a new block if the + * new size request fits in the old one and doesn't waste any space. + * Only free the old block if we successfully got a new one. + * [MCHECK] (struct header): New type. + * (union header): Only define if !MCHECK. + * (HEADER_SIZE, HEADER_NEXT, HEADER_FREE, HEADER_CHECK): New macros. + * [MCHECK] (MIN_SIZE): Add correct definition for this case. + * (more_memory, malloc, free, realloc): Use above macros, and add appropiate + * checks & frobs in MCHECK case. * - * Revision 1.9 1995/02/13 16:36:08 roland - * Include string.h; #define bcopy using memcpy. + * Revision 1.6 1996/03/07 21:13:08 miles + * (realloc): + * Use LOG2_MIN_SIZE. + * Don't bother allocating a new block if the new size request fits in the old + * one and doesn't waste any space. + * Only free the old block if we successfully got a new one. + * (LOG2_MIN_SIZE): New macro. * - * Revision 1.8 1995/02/03 01:54:21 roland - * Remove bogus bcopy decl. + * Revision 1.5 1996/03/06 23:51:04 miles + * [MCHECK] (struct header): New type. + * (union header): Only define if !MCHECK. + * (HEADER_SIZE, HEADER_NEXT, HEADER_FREE, HEADER_CHECK): New macros. + * [MCHECK] (MIN_SIZE): Add correct definition for this case. + * (more_memory, malloc, free, realloc): + * Use above macros, and add appropiate checks & frobs in MCHECK case. * - * Revision 1.7 1995/01/26 04:22:02 roland - * Don't include gnu-stabs.h. - * - * Revision 1.6 1994/12/07 19:41:26 roland - * (vm_allocate, vm_page_size): #define these to __ names at top. - * - * Revision 1.5 1994/06/04 01:48:44 roland + * Revision 1.4 1994/05/05 11:21:42 roland * entered into RCS * * Revision 2.7 91/05/14 17:57:34 mrt @@ -99,9 +114,11 @@ */ +#include <assert.h> + #include <cthreads.h> -#include "cthread_internals.h" +#define MCHECK /* * Structure of memory block header. @@ -109,12 +126,41 @@ * When allocated, fl points to free list. * Size of header is 4 bytes, so minimum usable block size is 8 bytes. */ + +#define CHECK_BUSY 0x8a3c743e +#define CHECK_FREE 0x66688b92 + +#ifdef MCHECK + +typedef struct header { + long check; + union { + struct header *next; + struct free_list *fl; + } u; +} *header_t; + +#define HEADER_SIZE sizeof (struct header) +#define HEADER_NEXT(h) ((h)->u.next) +#define HEADER_FREE(h) ((h)->u.fl) +#define HEADER_CHECK(h) ((h)->check) +#define MIN_SIZE 16 +#define LOG2_MIN_SIZE 4 + +#else /* ! MCHECK */ + typedef union header { union header *next; struct free_list *fl; } *header_t; +#define HEADER_SIZE sizeof (union header) +#define HEADER_NEXT(h) ((h)->next) +#define HEADER_FREE(h) ((h)->fl) #define MIN_SIZE 8 /* minimum block size */ +#define LOG2_MIN_SIZE 3 + +#endif /* MCHECK */ typedef struct free_list { spin_lock_t lock; /* spin lock for mutual exclusion */ @@ -125,10 +171,10 @@ typedef struct free_list { } *free_list_t; /* - * Free list with index i contains blocks of size 2^(i+3) including header. - * Smallest block size is 8, with 4 bytes available to user. - * Size argument to malloc is a signed integer for sanity checking, - * so largest block size is 2^31. + * Free list with index i contains blocks of size 2 ^ (i + LOG2_MIN_SIZE) + * including header. Smallest block size is MIN_SIZE, with MIN_SIZE - + * HEADER_SIZE bytes available to user. Size argument to malloc is a signed + * integer for sanity checking, so largest block size is 2^31. */ #define NBUCKETS 29 @@ -173,18 +219,23 @@ more_memory(size, fl) if (size <= vm_page_size) { amount = vm_page_size; n = vm_page_size / size; - /* - * We lose vm_page_size - n*size bytes here. */ + /* We lose vm_page_size - n*size bytes here. */ } else { amount = size; n = 1; } - MACH_CALL(vm_allocate(mach_task_self(), &where, (vm_size_t) amount, TRUE), r); + + r = vm_allocate(mach_task_self(), &where, (vm_size_t) amount, TRUE); + assert_perror (r); + h = (header_t) where; do { - h->next = fl->head; - fl->head = h; - h = (header_t) ((char *) h + size); + HEADER_NEXT (h) = fl->head; +#ifdef MCHECK + HEADER_CHECK (h) = CHECK_FREE; +#endif + fl->head = h; + h = (header_t) ((char *) h + size); } while (--n != 0); } @@ -199,7 +250,7 @@ malloc(size) if ((int) size < 0) /* sanity check */ return 0; - size += sizeof(union header); + size += HEADER_SIZE; /* * Find smallest power-of-two block size * big enough to hold requested size plus header. @@ -232,7 +283,13 @@ malloc(size) /* * Pop block from free list. */ - fl->head = h->next; + fl->head = HEADER_NEXT (h); + +#ifdef MCHECK + assert (HEADER_CHECK (h) == CHECK_FREE); + HEADER_CHECK (h) = CHECK_BUSY; +#endif + #ifdef DEBUG fl->in_use += 1; #endif DEBUG @@ -242,11 +299,11 @@ malloc(size) * so we can figure out where it goes * at free() time. */ - h->fl = fl; + HEADER_FREE (h) = fl; /* * Return pointer past the block header. */ - return ((char *) h) + sizeof(union header); + return ((char *) h) + HEADER_SIZE; } /* Declaration changed to standard one for GNU. */ @@ -263,8 +320,13 @@ free(base) /* * Find free list for block. */ - h = (header_t) (base - sizeof(union header)); - fl = h->fl; + h = (header_t) (base - HEADER_SIZE); + +#ifdef MCHECK + assert (HEADER_CHECK (h) == CHECK_BUSY); +#endif + + fl = HEADER_FREE (h); i = fl - malloc_free_list; /* * Sanity checks. @@ -281,7 +343,10 @@ free(base) * Push block on free list. */ spin_lock(&fl->lock); - h->next = fl->head; + HEADER_NEXT (h) = fl->head; +#ifdef MCHECK + HEADER_CHECK (h) = CHECK_FREE; +#endif fl->head = h; #ifdef DEBUG fl->in_use -= 1; @@ -308,8 +373,11 @@ realloc(old_base, new_size) /* * Find size of old block. */ - h = (header_t) (old_base - sizeof(union header)); - fl = h->fl; + h = (header_t) (old_base - HEADER_SIZE); +#ifdef MCHECK + assert (HEADER_CHECK (h) == CHECK_BUSY); +#endif + fl = HEADER_FREE (h); i = fl - malloc_free_list; /* * Sanity checks. @@ -323,16 +391,29 @@ realloc(old_base, new_size) return 0; } /* - * Free list with index i contains blocks of size 2^(i+3) including header. + * Free list with index i contains blocks of size + * 2 ^ (i + * LOG2_MIN_SIZE) including header. */ - old_size = (1 << (i+3)) - sizeof(union header); + old_size = (1 << (i + LOG2_MIN_SIZE)) - HEADER_SIZE; + + if (new_size <= old_size + && new_size > (((old_size + HEADER_SIZE) >> 1) - HEADER_SIZE)) + /* The new size still fits in the same block, and wouldn't fit in + the next smaller block! */ + return old_base; + /* * Allocate new block, copy old bytes, and free old block. */ new_base = malloc(new_size); - if (new_base != 0) - bcopy(old_base, new_base, (int) (old_size < new_size ? old_size : new_size)); - free(old_base); + if (new_base) + bcopy(old_base, new_base, + (int) (old_size < new_size ? old_size : new_size)); + + if (new_base || new_size == 0) + /* Free OLD_BASE, but only if the malloc didn't fail. */ + free (old_base); + return new_base; } @@ -354,7 +435,7 @@ print_malloc_free_list() spin_lock(&fl->lock); if (fl->in_use != 0 || fl->head != 0) { total_used += fl->in_use * size; - for (n = 0, h = fl->head; h != 0; h = h->next, n += 1) + for (n = 0, h = fl->head; h != 0; h = HEADER_NEXT (h), n += 1) ; total_free += n * size; fprintf(stderr, "%10d %10d %10d %10d\n", |