On 11.11.2012 18:22, Andrew Lunn wrote:
On Thu, Nov 08, 2012 at 07:38:57AM +0100, Marek Szyprowski wrote:
dmapool always calls dma_alloc_coherent() with GFP_ATOMIC flag,
regardless
the flags provided by the caller. This causes excessive pruning of emergency memory pools without any good reason. This patch changes
the code
to correctly use gfp flags provided by the dmapool caller. This should solve the dmapool usage on ARM architecture, where GFP_ATOMIC DMA allocations can be served only from the special, very limited memory
pool.
Reported-by: Soren Moch smoch@web.de
Please use Reported-by: Soeren Moch smoch@web.de
Reported-by: Thomas Petazzoni thomas.petazzoni@free-electrons.com Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com
Tested-by: Andrew Lunn andrew@lunn.ch
I tested this on a Kirkwood QNAP after removing the call to init_dma_coherent_pool_size().
Andrew
Tested-by: Soeren Moch smoch@web.de
Now I had a chance to test this patch on my Kirkwood guruplug system with linux-3.6.6 . It is running much better now, but with the original 256K coherent pool size I still see errors after several hours of runtime:
Nov 12 09:42:32 guru kernel: ERROR: 256 KiB atomic DMA coherent pool is too small! Nov 12 09:42:32 guru kernel: Please increase it with coherent_pool= kernel parameter!
Soeren
mm/dmapool.c | 27 +++++++-------------------- 1 file changed, 7 insertions(+), 20 deletions(-)
diff --git a/mm/dmapool.c b/mm/dmapool.c index c5ab33b..86de9b2 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -62,8 +62,6 @@ struct dma_page { /* cacheable header for
'allocation' bytes */
unsigned int offset;};
-#define POOL_TIMEOUT_JIFFIES ((100 /* msec */ * HZ) / 1000)
static DEFINE_MUTEX(pools_lock);
static ssize_t @@ -227,7 +225,6 @@ static struct dma_page *pool_alloc_page(struct
dma_pool *pool, gfp_t mem_flags)
memset(page->vaddr, POOL_POISON_FREED, pool->allocation);#endif pool_initialise_page(pool, page);
list_add(&page->page_list, &pool->page_list); page->in_use = 0; page->offset = 0;@@ -315,30 +312,21 @@ void *dma_pool_alloc(struct dma_pool *pool,
gfp_t mem_flags,
might_sleep_if(mem_flags & __GFP_WAIT); spin_lock_irqsave(&pool->lock, flags);
restart: list_for_each_entry(page, &pool->page_list, page_list) { if (page->offset < pool->allocation) goto ready; }
page = pool_alloc_page(pool, GFP_ATOMIC);
if (!page) {
if (mem_flags & __GFP_WAIT) {DECLARE_WAITQUEUE(wait, current);__set_current_state(TASK_UNINTERRUPTIBLE);__add_wait_queue(&pool->waitq, &wait);spin_unlock_irqrestore(&pool->lock, flags);
- /* pool_alloc_page() might sleep, so temporarily drop
&pool->lock */
- spin_unlock_irqrestore(&pool->lock, flags);
schedule_timeout(POOL_TIMEOUT_JIFFIES);
- page = pool_alloc_page(pool, mem_flags);
- if (!page)
return NULL;
spin_lock_irqsave(&pool->lock, flags);__remove_wait_queue(&pool->waitq, &wait);goto restart;}retval = NULL;goto done;- }
spin_lock_irqsave(&pool->lock, flags);
list_add(&page->page_list, &pool->page_list); ready: page->in_use++; offset = page->offset;
@@ -348,7 +336,6 @@ void *dma_pool_alloc(struct dma_pool *pool,
gfp_t mem_flags,
#ifdef DMAPOOL_DEBUG memset(retval, POOL_POISON_ALLOCATED, pool->size); #endif
- done: spin_unlock_irqrestore(&pool->lock, flags); return retval;
}
1.7.9.5