| Message ID | 20230524171904.3967031-16-catalin.marinas@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm, dma, arm64: Reduce ARCH_KMALLOC_MINALIGN to 8 | expand |
On 24/05/2023 6:19 pm, Catalin Marinas wrote: > With the DMA bouncing of unaligned kmalloc() buffers now in place, > enable it for arm64 to allow the kmalloc-{8,16,32,48,96} caches. In > addition, always create the swiotlb buffer even when the end of RAM is > within the 32-bit physical address range (the swiotlb buffer can still > be disabled on the kernel command line). > > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > --- > arch/arm64/Kconfig | 1 + > arch/arm64/mm/init.c | 7 ++++++- > 2 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index b1201d25a8a4..af42871431c0 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -120,6 +120,7 @@ config ARM64 > select CRC32 > select DCACHE_WORD_ACCESS > select DYNAMIC_FTRACE if FUNCTION_TRACER > + select DMA_BOUNCE_UNALIGNED_KMALLOC We may want to give the embedded folks an easier way of turning this off, since IIRC one of the reasons for the existing automatic behaviour was people not wanting to have to depend on the command line. Things with 256MB or so of RAM seem unlikely to get enough memory efficiency back from the smaller kmem caches to pay off the SWIOTLB allocation :) Cheers, Robin. > select DMA_DIRECT_REMAP > select EDAC_SUPPORT > select FRAME_POINTER > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index 66e70ca47680..3ac2e9d79ce4 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -442,7 +442,12 @@ void __init bootmem_init(void) > */ > void __init mem_init(void) > { > - swiotlb_init(max_pfn > PFN_DOWN(arm64_dma_phys_limit), SWIOTLB_VERBOSE); > + bool swiotlb = max_pfn > PFN_DOWN(arm64_dma_phys_limit); > + > + if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC)) > + swiotlb = true; > + > + swiotlb_init(swiotlb, SWIOTLB_VERBOSE); > > /* this will put all unused low memory onto the freelists */ > memblock_free_all();
On Thu, May 25, 2023 at 05:12:37PM +0100, Robin Murphy wrote: > On 24/05/2023 6:19 pm, Catalin Marinas wrote: > > With the DMA bouncing of unaligned kmalloc() buffers now in place, > > enable it for arm64 to allow the kmalloc-{8,16,32,48,96} caches. In > > addition, always create the swiotlb buffer even when the end of RAM is > > within the 32-bit physical address range (the swiotlb buffer can still > > be disabled on the kernel command line). > > > > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> > > Cc: Will Deacon <will@kernel.org> > > --- > > arch/arm64/Kconfig | 1 + > > arch/arm64/mm/init.c | 7 ++++++- > > 2 files changed, 7 insertions(+), 1 deletion(-) > > > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > > index b1201d25a8a4..af42871431c0 100644 > > --- a/arch/arm64/Kconfig > > +++ b/arch/arm64/Kconfig > > @@ -120,6 +120,7 @@ config ARM64 > > select CRC32 > > select DCACHE_WORD_ACCESS > > select DYNAMIC_FTRACE if FUNCTION_TRACER > > + select DMA_BOUNCE_UNALIGNED_KMALLOC > > We may want to give the embedded folks an easier way of turning this off, > since IIRC one of the reasons for the existing automatic behaviour was > people not wanting to have to depend on the command line. Things with 256MB > or so of RAM seem unlikely to get enough memory efficiency back from the > smaller kmem caches to pay off the SWIOTLB allocation :) I thought about this initially and that's why I had two options (ARCH_WANT_* and this one). But we already select SWIOTLB on arm64, so for the embedded folk the only option is swiotlb=noforce on the cmdline which, in turn, limits the kmalloc caches to kmalloc-64 (or whatever the cache line size is) irrespective of this new select.
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index b1201d25a8a4..af42871431c0 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -120,6 +120,7 @@ config ARM64 select CRC32 select DCACHE_WORD_ACCESS select DYNAMIC_FTRACE if FUNCTION_TRACER + select DMA_BOUNCE_UNALIGNED_KMALLOC select DMA_DIRECT_REMAP select EDAC_SUPPORT select FRAME_POINTER diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 66e70ca47680..3ac2e9d79ce4 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -442,7 +442,12 @@ void __init bootmem_init(void) */ void __init mem_init(void) { - swiotlb_init(max_pfn > PFN_DOWN(arm64_dma_phys_limit), SWIOTLB_VERBOSE); + bool swiotlb = max_pfn > PFN_DOWN(arm64_dma_phys_limit); + + if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC)) + swiotlb = true; + + swiotlb_init(swiotlb, SWIOTLB_VERBOSE); /* this will put all unused low memory onto the freelists */ memblock_free_all();
With the DMA bouncing of unaligned kmalloc() buffers now in place, enable it for arm64 to allow the kmalloc-{8,16,32,48,96} caches. In addition, always create the swiotlb buffer even when the end of RAM is within the 32-bit physical address range (the swiotlb buffer can still be disabled on the kernel command line). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> --- arch/arm64/Kconfig | 1 + arch/arm64/mm/init.c | 7 ++++++- 2 files changed, 7 insertions(+), 1 deletion(-)