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* [PATCH] mm: dmapool: use provided gfp flags for all dma_alloc_coherent() calls
@ 2012-11-08  6:38 Marek Szyprowski
  2012-11-11 17:22 ` Andrew Lunn
  2012-11-19  0:18 ` Jason Cooper
  0 siblings, 2 replies; 59+ messages in thread
From: Marek Szyprowski @ 2012-11-08  6:38 UTC (permalink / raw)
  To: linux-arm-kernel, linaro-mm-sig, linux-mm, linux-kernel
  Cc: Marek Szyprowski, Kyungmin Park, Arnd Bergmann, Soren Moch,
	Thomas Petazzoni, Sebastian Hesselbarth, Andrew Lunn

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>
Reported-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 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;
 	} else {
@@ -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


^ permalink raw reply related	[flat|nested] 59+ messages in thread

end of thread, other threads:[~2013-01-29 11:52 UTC | newest]

Thread overview: 59+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-11-08  6:38 [PATCH] mm: dmapool: use provided gfp flags for all dma_alloc_coherent() calls Marek Szyprowski
2012-11-11 17:22 ` Andrew Lunn
2012-11-12  9:48   ` Soeren Moch
2012-11-12 10:38     ` Andrew Lunn
2012-11-12 11:03       ` Soeren Moch
2012-11-19  0:18 ` Jason Cooper
2012-11-19 22:48   ` Andrew Morton
2012-11-20 10:48     ` Marek Szyprowski
2012-11-20 19:52       ` Andrew Morton
2012-11-20 14:31     ` [PATCH v2] " Marek Szyprowski
2012-11-20 19:33       ` Andrew Morton
2012-11-20 20:27         ` Jason Cooper
2012-11-21  8:08         ` Marek Szyprowski
2012-11-21  8:36           ` Andrew Morton
2012-11-21  9:20             ` Marek Szyprowski
2012-11-21 19:17               ` Andrew Morton
2012-11-22 12:55                 ` Marek Szyprowski
2013-01-14 11:56       ` Soeren Moch
2013-01-15 16:56         ` Jason Cooper
2013-01-15 17:50           ` Greg KH
2013-01-15 20:16             ` Jason Cooper
2013-01-15 21:56               ` Jason Cooper
2013-01-16  0:17                 ` Soeren Moch
2013-01-16  2:40                   ` Jason Cooper
2013-01-16  3:24                     ` Soeren Moch
2013-01-16  8:55                       ` Soeren Moch
2013-01-16 15:50                         ` [PATCH] ata: sata_mv: fix sg_tbl_pool alignment Jason Cooper
2013-01-16 17:05                           ` Soeren Moch
2013-01-16 17:52                             ` Jason Cooper
2013-01-16 18:35                               ` Jason Cooper
2013-01-16 22:26                                 ` Soeren Moch
2013-01-16 23:10                               ` Soeren Moch
2013-01-17  9:11                               ` Soeren Moch
2013-01-16 17:32                         ` [PATCH v2] mm: dmapool: use provided gfp flags for all dma_alloc_coherent() calls Soeren Moch
2013-01-16 17:47                           ` Jason Cooper
2013-01-16 22:36                             ` Soeren Moch
2013-01-17 10:49                       ` Arnd Bergmann
2013-01-17 13:47                         ` Soeren Moch
2013-01-17 20:26                           ` Arnd Bergmann
2013-01-19 15:29                             ` Soeren Moch
2013-01-19 18:59                               ` Andrew Lunn
2013-01-23 15:30                                 ` Soeren Moch
2013-01-23 16:25                                   ` Andrew Lunn
2013-01-23 17:07                                     ` Soeren Moch
2013-01-23 17:20                                       ` Soeren Moch
2013-01-23 18:10                                         ` Andrew Lunn
2013-01-28 20:59                                           ` Soeren Moch
2013-01-29  0:13                                             ` Jason Cooper
2013-01-29 11:02                                             ` Andrew Lunn
2013-01-29 11:50                                               ` Soeren Moch
2013-01-19 20:05                               ` Arnd Bergmann
2013-01-21 15:01                                 ` Soeren Moch
2013-01-21 18:55                                   ` Arnd Bergmann
2013-01-21 21:01                                     ` Greg KH
2013-01-22 18:13                                       ` Arnd Bergmann
2013-01-23 14:37                                         ` Soeren Moch
2013-01-19 16:24                             ` Andrew Lunn
2013-01-15 20:05           ` Sebastian Hesselbarth
2013-01-15 20:19             ` Jason Cooper

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