[rfc 6/6] dma-remap: double the default DMA coherent pool size

[David Rientjes]

When AMD memory encryption is enabled, some devices may used more than
256KB/sec from the atomic pools.  Double the default size to make the
original size and expansion more appropriate.

This provides a slight optimization on initial expansion and is deemed
appropriate for all configs with CONFIG_DMA_REMAP enabled because of the
increased reliance on the atomic pools.

Alternatively, this could be done only when CONFIG_AMD_MEM_ENCRYPT is
enabled.

Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
---
 kernel/dma/remap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c
--- a/kernel/dma/remap.c
+++ b/kernel/dma/remap.c
@@ -105,7 +105,7 @@ static struct gen_pool *atomic_pool __ro_after_init;
 static struct gen_pool *atomic_pool_dma32 __ro_after_init;
 static struct gen_pool *atomic_pool_normal __ro_after_init;
 
-#define DEFAULT_DMA_COHERENT_POOL_SIZE  SZ_256K
+#define DEFAULT_DMA_COHERENT_POOL_SIZE  SZ_512K
 static size_t atomic_pool_size = DEFAULT_DMA_COHERENT_POOL_SIZE;
 
 /* Dynamic background expansion when the atomic pool is near capacity */