Currently a call to dma_pool_alloc() with a ___GFP_ZERO flag returns a non-zeroed memory region. This patchset adds support for the __GFP_ZERO flag to dma_pool_alloc(), adds 2 wrapper functions for allocing zeroed memory from a pool, and provides a coccinelle script for finding & replacing instances of dma_pool_alloc() followed by memset(0) with a single dma_pool_zalloc() call. Changes from v1 to v2: - don't memset() POOL_POISON_ALLOCATED in dma_pool_alloc() if __GFP_ZERO is set - Ran test to see how often pool_alloc_page() is called There was some concern that this always calls memset() to zero, instead of passing __GFP_ZERO into the page allocator. [https://lkml.org/lkml/2015/7/15/881] I ran a test on my system to get an idea of how often dma_pool_alloc() calls into pool_alloc_page(). After Boot: [ 30.119863] alloc_calls:541, page_allocs:7 After an hour: [ 3600.951031] alloc_calls:9566, page_allocs:12 After copying 1GB file onto a USB drive: [ 4260.657148] alloc_calls:17225, page_allocs:12 It doesn't look like dma_pool_alloc() calls down to the page allocator very often (at least on my system). Sean O. Stalley (4): mm: Add support for __GFP_ZERO flag to dma_pool_alloc() mm: Add dma_pool_zalloc() call to DMA API pci: mm: Add pci_pool_zalloc() call coccinelle: mm: scripts/coccinelle/api/alloc/pool_zalloc-simple.cocci Documentation/DMA-API.txt | 7 ++ include/linux/dmapool.h | 6 ++ include/linux/pci.h | 2 + mm/dmapool.c | 9 ++- .../coccinelle/api/alloc/pool_zalloc-simple.cocci | 84 ++++++++++++++++++++++ 5 files changed, 106 insertions(+), 2 deletions(-) create mode 100644 scripts/coccinelle/api/alloc/pool_zalloc-simple.cocci -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
