[PATCH] drm/ttm: Allocate the page pool manager in the heap.
Francisco Jerez
currojerez at riseup.net
Sat Jul 3 19:03:07 PDT 2010
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.
Signed-off-by: Francisco Jerez <currojerez at riseup.net>
---
drivers/gpu/drm/ttm/ttm_page_alloc.c | 68 ++++++++++++++++-----------------
include/drm/ttm/ttm_page_alloc.h | 4 --
2 files changed, 33 insertions(+), 39 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c b/drivers/gpu/drm/ttm/ttm_page_alloc.c
index ef91069..fc68a66 100644
--- a/drivers/gpu/drm/ttm/ttm_page_alloc.c
+++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c
@@ -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 {
@@ -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,
@@ -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)
@@ -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. */
@@ -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;
}
@@ -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 */
@@ -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
@@ -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)
@@ -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;
}
@@ -820,16 +820,14 @@ 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)
@@ -837,14 +835,14 @@ 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,
diff --git a/include/drm/ttm/ttm_page_alloc.h b/include/drm/ttm/ttm_page_alloc.h
index 8bb4de5..1168214 100644
--- a/include/drm/ttm/ttm_page_alloc.h
+++ b/include/drm/ttm/ttm_page_alloc.h
@@ -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);
/**
--
1.6.4.4
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