* [PATCH] dma-mapping: Reduce dma_mapping_error() inline bloat
@ 2017-07-24 17:29 ` Robin Murphy
2017-08-01 7:58 ` Marek Szyprowski
2017-08-25 14:56 ` Christoph Hellwig
0 siblings, 2 replies; 3+ messages in thread
From: Robin Murphy @ 2017-07-24 17:29 UTC (permalink / raw)
To: hch, m.szyprowski; +Cc: linux-kernel
Thanks to the nested inlining, all drivers correctly calling
dma_mapping_error() after a mapping a page or single buffer generate two
calls to get_arch_dma_ops() per callsite, which all adds up to a fair
old chunk of useless code, e.g. ~3KB for an arm64 defconfig plus extras:
text data bss dec hex filename
13051391 1503898 327768 14883057 e318f1 vmlinux.o.old
13050751 1503898 327768 14882417 e31671 vmlinux.o.new
Give the compiler a hand by making it clear we want the same ops.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
include/linux/dma-mapping.h | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 843ab866e0f4..239e53d12ee8 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -541,10 +541,11 @@ static inline void dma_free_noncoherent(struct device *dev, size_t size,
static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
- debug_dma_mapping_error(dev, dma_addr);
+ const struct dma_map_ops *ops = get_dma_ops(dev);
- if (get_dma_ops(dev)->mapping_error)
- return get_dma_ops(dev)->mapping_error(dev, dma_addr);
+ debug_dma_mapping_error(dev, dma_addr);
+ if (ops->mapping_error)
+ return ops->mapping_error(dev, dma_addr);
return 0;
}
--
2.12.2.dirty
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] dma-mapping: Reduce dma_mapping_error() inline bloat
2017-07-24 17:29 ` [PATCH] dma-mapping: Reduce dma_mapping_error() inline bloat Robin Murphy
@ 2017-08-01 7:58 ` Marek Szyprowski
2017-08-25 14:56 ` Christoph Hellwig
1 sibling, 0 replies; 3+ messages in thread
From: Marek Szyprowski @ 2017-08-01 7:58 UTC (permalink / raw)
To: Robin Murphy, hch; +Cc: linux-kernel
Hi Robin,
On 2017-07-24 19:29, Robin Murphy wrote:
> Thanks to the nested inlining, all drivers correctly calling
> dma_mapping_error() after a mapping a page or single buffer generate two
> calls to get_arch_dma_ops() per callsite, which all adds up to a fair
> old chunk of useless code, e.g. ~3KB for an arm64 defconfig plus extras:
>
> text data bss dec hex filename
> 13051391 1503898 327768 14883057 e318f1 vmlinux.o.old
> 13050751 1503898 327768 14882417 e31671 vmlinux.o.new
>
> Give the compiler a hand by making it clear we want the same ops.
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>
Similar pattern is used in drivers/xen/swiotlb-xen.c for mmap and
get_sgtable. This could be also fixed, although those are not used so
frequently as dma_mapping_error.
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
> include/linux/dma-mapping.h | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index 843ab866e0f4..239e53d12ee8 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -541,10 +541,11 @@ static inline void dma_free_noncoherent(struct device *dev, size_t size,
>
> static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
> {
> - debug_dma_mapping_error(dev, dma_addr);
> + const struct dma_map_ops *ops = get_dma_ops(dev);
>
> - if (get_dma_ops(dev)->mapping_error)
> - return get_dma_ops(dev)->mapping_error(dev, dma_addr);
> + debug_dma_mapping_error(dev, dma_addr);
> + if (ops->mapping_error)
> + return ops->mapping_error(dev, dma_addr);
> return 0;
> }
>
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] dma-mapping: Reduce dma_mapping_error() inline bloat
2017-07-24 17:29 ` [PATCH] dma-mapping: Reduce dma_mapping_error() inline bloat Robin Murphy
2017-08-01 7:58 ` Marek Szyprowski
@ 2017-08-25 14:56 ` Christoph Hellwig
1 sibling, 0 replies; 3+ messages in thread
From: Christoph Hellwig @ 2017-08-25 14:56 UTC (permalink / raw)
To: Robin Murphy; +Cc: hch, m.szyprowski, linux-kernel
Thanks,
applied to the dma-mapping-4.14 tree.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-07-24 17:29 ` [PATCH] dma-mapping: Reduce dma_mapping_error() inline bloat Robin Murphy
2017-08-01 7:58 ` Marek Szyprowski
2017-08-25 14:56 ` Christoph Hellwig
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