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Extract the fragment allocation code from the nursery allocation entr…
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…ypoints.
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@kumpera
kumpera committed Mar 30, 2012
1 parent 1a60868 commit 96dec56
Showing 1 changed file with 144 additions and 82 deletions.
226 changes: 144 additions & 82 deletions mono/metadata/sgen-nursery-allocator.c
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Original file line number Diff line number Diff line change
Expand Up @@ -396,7 +396,7 @@ claim_remaining_size (Fragment *frag, char *alloc_end)
}

static void*
alloc_from_fragment (FragmentAllocator *allocator, Fragment *frag, size_t size)
par_alloc_from_fragment (FragmentAllocator *allocator, Fragment *frag, size_t size)
{
char *p = frag->fragment_next;
char *end = p + size;
Expand Down Expand Up @@ -461,6 +461,147 @@ alloc_from_fragment (FragmentAllocator *allocator, Fragment *frag, size_t size)
return p;
}

static void*
serial_alloc_from_fragment (Fragment **previous, Fragment *frag, size_t size)
{
char *p = frag->fragment_next;
char *end = p + size;

if (end > frag->fragment_end)
return NULL;

frag->fragment_next = end;

if (frag->fragment_end - end < SGEN_MAX_NURSERY_WASTE) {
*previous = frag->next;

/* Clear the remaining space, pinning depends on this. FIXME move this to use phony arrays */
memset (end, 0, frag->fragment_end - end);

*previous = frag->next;
}

return p;
}

static void*
par_alloc (FragmentAllocator *allocator, size_t size)
{
Fragment *frag;

#ifdef NALLOC_DEBUG
InterlockedIncrement (&alloc_count);
#endif

restart:
for (frag = unmask (allocator->alloc_head); unmask (frag); frag = unmask (frag->next)) {
HEAVY_STAT (InterlockedIncrement (&stat_alloc_iterations));

if (size <= (frag->fragment_end - frag->fragment_next)) {
void *p = par_alloc_from_fragment (allocator, frag, size);
if (!p) {
HEAVY_STAT (InterlockedIncrement (&stat_alloc_retries));
goto restart;
}
#ifdef NALLOC_DEBUG
add_alloc_record (p, size, FIXED_ALLOC);
#endif
return p;
}
}
return NULL;
}

static void*
serial_alloc (FragmentAllocator *allocator, size_t size)
{
Fragment *frag;
Fragment **previous;
#ifdef NALLOC_DEBUG
InterlockedIncrement (&alloc_count);
#endif

previous = &allocator->alloc_head;

for (frag = *previous; frag; frag = *previous) {
HEAVY_STAT (InterlockedIncrement (&stat_alloc_iterations));
char *p = serial_alloc_from_fragment (previous, frag, size);
if (p) {
#ifdef NALLOC_DEBUG
add_alloc_record (p, size, FIXED_ALLOC);
#endif
return p;
}
previous = &frag->next;
}
return NULL;
}

static void*
par_range_alloc (FragmentAllocator *allocator, size_t desired_size, size_t minimum_size, int *out_alloc_size)
{
Fragment *frag, *min_frag;
restart:
min_frag = NULL;

#ifdef NALLOC_DEBUG
InterlockedIncrement (&alloc_count);
#endif

for (frag = unmask (allocator->alloc_head); frag; frag = unmask (frag->next)) {
int frag_size = frag->fragment_end - frag->fragment_next;

HEAVY_STAT (InterlockedIncrement (&stat_alloc_range_iterations));

if (desired_size <= frag_size) {
void *p;
*out_alloc_size = desired_size;

p = par_alloc_from_fragment (allocator, frag, desired_size);
if (!p) {
HEAVY_STAT (InterlockedIncrement (&stat_alloc_range_retries));
goto restart;
}
#ifdef NALLOC_DEBUG
add_alloc_record (p, desired_size, RANGE_ALLOC);
#endif
return p;
}
if (minimum_size <= frag_size)
min_frag = frag;
}

/* The second fragment_next read should be ordered in respect to the first code block */
mono_memory_barrier ();

if (min_frag) {
void *p;
int frag_size;

frag_size = min_frag->fragment_end - min_frag->fragment_next;
if (frag_size < minimum_size)
goto restart;

*out_alloc_size = frag_size;

mono_memory_barrier ();
p = par_alloc_from_fragment (allocator, min_frag, frag_size);

/*XXX restarting here is quite dubious given this is already second chance allocation. */
if (!p) {
HEAVY_STAT (InterlockedIncrement (&stat_alloc_retries));
goto restart;
}
#ifdef NALLOC_DEBUG
add_alloc_record (p, frag_size, RANGE_ALLOC);
#endif
return p;
}

return NULL;
}


void
mono_sgen_clear_current_nursery_fragment (void)
{
Expand Down Expand Up @@ -629,101 +770,22 @@ mono_sgen_can_alloc_size (size_t size)
void*
mono_sgen_nursery_alloc (size_t size)
{
Fragment *frag;
DEBUG (4, fprintf (gc_debug_file, "Searching nursery for size: %zd\n", size));
size = SGEN_ALIGN_UP (size);

HEAVY_STAT (InterlockedIncrement (&stat_nursery_alloc_requests));

#ifdef NALLOC_DEBUG
InterlockedIncrement (&alloc_count);
#endif

restart:
for (frag = unmask (nursery_allocator.alloc_head); frag; frag = unmask (frag->next)) {
HEAVY_STAT (InterlockedIncrement (&stat_alloc_iterations));

if (size <= (frag->fragment_end - frag->fragment_next)) {
void *p = alloc_from_fragment (&nursery_allocator, frag, size);
if (!p) {
HEAVY_STAT (InterlockedIncrement (&stat_alloc_retries));
goto restart;
}
#ifdef NALLOC_DEBUG
add_alloc_record (p, size, FIXED_ALLOC);
#endif
return p;
}
}
return NULL;
return par_alloc (&nursery_allocator, size);
}

void*
mono_sgen_nursery_alloc_range (size_t desired_size, size_t minimum_size, int *out_alloc_size)
{
Fragment *frag, *min_frag;
DEBUG (4, fprintf (gc_debug_file, "Searching for byte range desired size: %zd minimum size %zd\n", desired_size, minimum_size));

HEAVY_STAT (InterlockedIncrement (&stat_nursery_alloc_range_requests));

restart:
min_frag = NULL;

#ifdef NALLOC_DEBUG
InterlockedIncrement (&alloc_count);
#endif

for (frag = unmask (nursery_allocator.alloc_head); frag; frag = unmask (frag->next)) {
int frag_size = frag->fragment_end - frag->fragment_next;

HEAVY_STAT (InterlockedIncrement (&stat_alloc_range_iterations));

if (desired_size <= frag_size) {
void *p;
*out_alloc_size = desired_size;

p = alloc_from_fragment (&nursery_allocator, frag, desired_size);
if (!p) {
HEAVY_STAT (InterlockedIncrement (&stat_alloc_range_retries));
goto restart;
}
#ifdef NALLOC_DEBUG
add_alloc_record (p, desired_size, RANGE_ALLOC);
#endif
return p;
}
if (minimum_size <= frag_size)
min_frag = frag;
}

/* The second fragment_next read should be ordered in respect to the first code block */
mono_memory_barrier ();

if (min_frag) {
void *p;
int frag_size;

frag_size = min_frag->fragment_end - min_frag->fragment_next;
if (frag_size < minimum_size)
goto restart;

*out_alloc_size = frag_size;

mono_memory_barrier ();
p = alloc_from_fragment (&nursery_allocator, min_frag, frag_size);

/*XXX restarting here is quite dubious given this is already second chance allocation. */
if (!p) {
HEAVY_STAT (InterlockedIncrement (&stat_alloc_retries));
goto restart;
}
#ifdef NALLOC_DEBUG
add_alloc_record (p, frag_size, RANGE_ALLOC);
#endif
return p;
}

return NULL;
return par_range_alloc (&nursery_allocator, desired_size, minimum_size, out_alloc_size);
}

/*** Initialization ***/
Expand Down

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