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drm/ttm: Allocate the page pool manager in the heap.
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Repeated ttm_page_alloc_init/fini fails noisily because the pool
manager kobj isn't zeroed out between uses (we could do just that but
statically allocated kobjects are generally considered a bad thing).
Move it to kzalloc'ed memory.

Note that this patch drops the refcounting behavior of the pool
allocator init/fini functions: it would have led to a race condition
in its current form, and anyway it was never exploited.

This fixes a regression with reloading kms modules at runtime, since
page allocator was introduced.

Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
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Francisco Jerez authored and Dave Airlie committed Jul 7, 2010
1 parent 123f94f commit 5870a4d
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Showing 2 changed files with 33 additions and 39 deletions.
68 changes: 33 additions & 35 deletions drivers/gpu/drm/ttm/ttm_page_alloc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -104,7 +104,6 @@ struct ttm_pool_opts {
struct ttm_pool_manager {
struct kobject kobj;
struct shrinker mm_shrink;
atomic_t page_alloc_inited;
struct ttm_pool_opts options;

union {
Expand Down Expand Up @@ -142,7 +141,7 @@ static void ttm_pool_kobj_release(struct kobject *kobj)
{
struct ttm_pool_manager *m =
container_of(kobj, struct ttm_pool_manager, kobj);
(void)m;
kfree(m);
}

static ssize_t ttm_pool_store(struct kobject *kobj,
Expand Down Expand Up @@ -214,9 +213,7 @@ static struct kobj_type ttm_pool_kobj_type = {
.default_attrs = ttm_pool_attrs,
};

static struct ttm_pool_manager _manager = {
.page_alloc_inited = ATOMIC_INIT(0)
};
static struct ttm_pool_manager *_manager;

#ifndef CONFIG_X86
static int set_pages_array_wb(struct page **pages, int addrinarray)
Expand Down Expand Up @@ -271,7 +268,7 @@ static struct ttm_page_pool *ttm_get_pool(int flags,
if (flags & TTM_PAGE_FLAG_DMA32)
pool_index |= 0x2;

return &_manager.pools[pool_index];
return &_manager->pools[pool_index];
}

/* set memory back to wb and free the pages. */
Expand Down Expand Up @@ -387,7 +384,7 @@ static int ttm_pool_get_num_unused_pages(void)
unsigned i;
int total = 0;
for (i = 0; i < NUM_POOLS; ++i)
total += _manager.pools[i].npages;
total += _manager->pools[i].npages;

return total;
}
Expand All @@ -408,7 +405,7 @@ static int ttm_pool_mm_shrink(int shrink_pages, gfp_t gfp_mask)
unsigned nr_free = shrink_pages;
if (shrink_pages == 0)
break;
pool = &_manager.pools[(i + pool_offset)%NUM_POOLS];
pool = &_manager->pools[(i + pool_offset)%NUM_POOLS];
shrink_pages = ttm_page_pool_free(pool, nr_free);
}
/* return estimated number of unused pages in pool */
Expand Down Expand Up @@ -576,10 +573,10 @@ static void ttm_page_pool_fill_locked(struct ttm_page_pool *pool,

/* If allocation request is small and there is not enough
* pages in pool we fill the pool first */
if (count < _manager.options.small
if (count < _manager->options.small
&& count > pool->npages) {
struct list_head new_pages;
unsigned alloc_size = _manager.options.alloc_size;
unsigned alloc_size = _manager->options.alloc_size;

/**
* Can't change page caching if in irqsave context. We have to
Expand Down Expand Up @@ -759,8 +756,8 @@ void ttm_put_pages(struct list_head *pages, unsigned page_count, int flags,
pool->npages += page_count;
/* Check that we don't go over the pool limit */
page_count = 0;
if (pool->npages > _manager.options.max_size) {
page_count = pool->npages - _manager.options.max_size;
if (pool->npages > _manager->options.max_size) {
page_count = pool->npages - _manager->options.max_size;
/* free at least NUM_PAGES_TO_ALLOC number of pages
* to reduce calls to set_memory_wb */
if (page_count < NUM_PAGES_TO_ALLOC)
Expand All @@ -785,33 +782,36 @@ static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, int flags,
int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
{
int ret;
if (atomic_add_return(1, &_manager.page_alloc_inited) > 1)
return 0;

WARN_ON(_manager);

printk(KERN_INFO TTM_PFX "Initializing pool allocator.\n");

ttm_page_pool_init_locked(&_manager.wc_pool, GFP_HIGHUSER, "wc");
_manager = kzalloc(sizeof(*_manager), GFP_KERNEL);

ttm_page_pool_init_locked(&_manager.uc_pool, GFP_HIGHUSER, "uc");
ttm_page_pool_init_locked(&_manager->wc_pool, GFP_HIGHUSER, "wc");

ttm_page_pool_init_locked(&_manager.wc_pool_dma32, GFP_USER | GFP_DMA32,
"wc dma");
ttm_page_pool_init_locked(&_manager->uc_pool, GFP_HIGHUSER, "uc");

ttm_page_pool_init_locked(&_manager.uc_pool_dma32, GFP_USER | GFP_DMA32,
"uc dma");
ttm_page_pool_init_locked(&_manager->wc_pool_dma32,
GFP_USER | GFP_DMA32, "wc dma");

_manager.options.max_size = max_pages;
_manager.options.small = SMALL_ALLOCATION;
_manager.options.alloc_size = NUM_PAGES_TO_ALLOC;
ttm_page_pool_init_locked(&_manager->uc_pool_dma32,
GFP_USER | GFP_DMA32, "uc dma");

kobject_init(&_manager.kobj, &ttm_pool_kobj_type);
ret = kobject_add(&_manager.kobj, &glob->kobj, "pool");
_manager->options.max_size = max_pages;
_manager->options.small = SMALL_ALLOCATION;
_manager->options.alloc_size = NUM_PAGES_TO_ALLOC;

ret = kobject_init_and_add(&_manager->kobj, &ttm_pool_kobj_type,
&glob->kobj, "pool");
if (unlikely(ret != 0)) {
kobject_put(&_manager.kobj);
kobject_put(&_manager->kobj);
_manager = NULL;
return ret;
}

ttm_pool_mm_shrink_init(&_manager);
ttm_pool_mm_shrink_init(_manager);

return 0;
}
Expand All @@ -820,31 +820,29 @@ void ttm_page_alloc_fini()
{
int i;

if (atomic_sub_return(1, &_manager.page_alloc_inited) > 0)
return;

printk(KERN_INFO TTM_PFX "Finalizing pool allocator.\n");
ttm_pool_mm_shrink_fini(&_manager);
ttm_pool_mm_shrink_fini(_manager);

for (i = 0; i < NUM_POOLS; ++i)
ttm_page_pool_free(&_manager.pools[i], FREE_ALL_PAGES);
ttm_page_pool_free(&_manager->pools[i], FREE_ALL_PAGES);

kobject_put(&_manager.kobj);
kobject_put(&_manager->kobj);
_manager = NULL;
}

int ttm_page_alloc_debugfs(struct seq_file *m, void *data)
{
struct ttm_page_pool *p;
unsigned i;
char *h[] = {"pool", "refills", "pages freed", "size"};
if (atomic_read(&_manager.page_alloc_inited) == 0) {
if (!_manager) {
seq_printf(m, "No pool allocator running.\n");
return 0;
}
seq_printf(m, "%6s %12s %13s %8s\n",
h[0], h[1], h[2], h[3]);
for (i = 0; i < NUM_POOLS; ++i) {
p = &_manager.pools[i];
p = &_manager->pools[i];

seq_printf(m, "%6s %12ld %13ld %8d\n",
p->name, p->nrefills,
Expand Down
4 changes: 0 additions & 4 deletions include/drm/ttm/ttm_page_alloc.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -56,10 +56,6 @@ void ttm_put_pages(struct list_head *pages,
enum ttm_caching_state cstate);
/**
* Initialize pool allocator.
*
* Pool allocator is internaly reference counted so it can be initialized
* multiple times but ttm_page_alloc_fini has to be called same number of
* times.
*/
int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages);
/**
Expand Down

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