| Message ID | 20240325110036.1564-1-jszhang@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | fc7a50eed9860d4b01e4ddc38f2a538d79f2e7b4 |
| Headers | show |
| Series | [v3,RESEND] riscv: mm: still create swiotlb buffer for kmalloc() bouncing if required | expand |
Hello: This patch was applied to riscv/linux.git (for-next) by Palmer Dabbelt <palmer@rivosinc.com>: On Mon, 25 Mar 2024 19:00:36 +0800 you wrote: > After commit f51f7a0fc2f4 ("riscv: enable DMA_BOUNCE_UNALIGNED_KMALLOC > for !dma_coherent"), for non-coherent platforms with less than 4GB > memory, we rely on users to pass "swiotlb=mmnn,force" kernel parameters > to enable DMA bouncing for unaligned kmalloc() buffers. Now let's go > further: If no bouncing needed for ZONE_DMA, let kernel automatically > allocate 1MB swiotlb buffer per 1GB of RAM for kmalloc() bouncing on > non-coherent platforms, so that no need to pass "swiotlb=mmnn,force" > any more. > > [...] Here is the summary with links: - [v3,RESEND] riscv: mm: still create swiotlb buffer for kmalloc() bouncing if required https://git.kernel.org/riscv/c/fc7a50eed986 You are awesome, thank you!
Hi Jisheng, On Mon, Mar 25, 2024 at 12:15 PM Jisheng Zhang <jszhang@kernel.org> wrote: > After commit f51f7a0fc2f4 ("riscv: enable DMA_BOUNCE_UNALIGNED_KMALLOC > for !dma_coherent"), for non-coherent platforms with less than 4GB > memory, we rely on users to pass "swiotlb=mmnn,force" kernel parameters > to enable DMA bouncing for unaligned kmalloc() buffers. Now let's go > further: If no bouncing needed for ZONE_DMA, let kernel automatically > allocate 1MB swiotlb buffer per 1GB of RAM for kmalloc() bouncing on > non-coherent platforms, so that no need to pass "swiotlb=mmnn,force" > any more. > > The math of "1MB swiotlb buffer per 1GB of RAM for kmalloc() bouncing" > is taken from arm64. Users can still force smaller swiotlb buffer by > passing "swiotlb=mmnn". > > Signed-off-by: Jisheng Zhang <jszhang@kernel.org> > Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Thanks for your patch, which is now commit fc7a50eed9860d4b ("riscv: mm: still create swiotlb buffer for kmalloc() bouncing if required") in riscv/for-next (next-20240429 and later). On RZ/Five, which has 1 GiB of RAM, i.e. a bit less for free use: Inode-cache hash table entries: 65536 (order: 7, 524288 bytes, linear) Built 1 zonelists, mobility grouping on. Total pages: 225792 mem auto-init: stack:off, heap alloc:off, heap free:off +software IO TLB: SWIOTLB bounce buffer size adjusted to 0MB ^^^ +software IO TLB: area num 1. +software IO TLB: mapped [mem 0x000000007ef56000-0x000000007f056000] (1MB) ^^^ Virtual kernel memory layout: I was a bit intrigued by the "0MB". However, that seems to be correct: mem_init: memblock_phys_mem_size() = 939524096 mem_init: size = 917504 mem_init: swiotlb_size_or_default() = 67108864 and it must be rounded up to 1 MB later. Apparently arm64 has the same discrepancy, which I never really noticed before (and I have no arm64 platforms with 1 GiB RAM or less): mem_init: memblock_phys_mem_size() = 2013265920 mem_init: size = 1966080 mem_init: swiotlb_size_or_default() = 67108864 software IO TLB: SWIOTLB bounce buffer size adjusted to 1MB ^^^ software IO TLB: area num 2. software IO TLB: mapped [mem 0x00000000b9400000-0x00000000b9600000] (2MB) ^^^ > --- a/arch/riscv/mm/init.c > +++ b/arch/riscv/mm/init.c > @@ -161,11 +161,25 @@ static void print_vm_layout(void) { } > > void __init mem_init(void) > { > + bool swiotlb = max_pfn > PFN_DOWN(dma32_phys_limit); > #ifdef CONFIG_FLATMEM > BUG_ON(!mem_map); > #endif /* CONFIG_FLATMEM */ > > - swiotlb_init(max_pfn > PFN_DOWN(dma32_phys_limit), SWIOTLB_VERBOSE); > + if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && !swiotlb && > + dma_cache_alignment != 1) { > + /* > + * If no bouncing needed for ZONE_DMA, allocate 1MB swiotlb > + * buffer per 1GB of RAM for kmalloc() bouncing on > + * non-coherent platforms. > + */ > + unsigned long size = > + DIV_ROUND_UP(memblock_phys_mem_size(), 1024); > + swiotlb_adjust_size(min(swiotlb_size_or_default(), size)); > + swiotlb = true; > + } > + > + swiotlb_init(swiotlb, SWIOTLB_VERBOSE); > memblock_free_all(); > > print_vm_layout(); Gr{oetje,eeting}s, Geert
diff --git a/arch/riscv/include/asm/cache.h b/arch/riscv/include/asm/cache.h index 2174fe7bac9a..570e9d8acad1 100644 --- a/arch/riscv/include/asm/cache.h +++ b/arch/riscv/include/asm/cache.h @@ -26,8 +26,8 @@ #ifndef __ASSEMBLY__ -#ifdef CONFIG_RISCV_DMA_NONCOHERENT extern int dma_cache_alignment; +#ifdef CONFIG_RISCV_DMA_NONCOHERENT #define dma_get_cache_alignment dma_get_cache_alignment static inline int dma_get_cache_alignment(void) { diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index fe8e159394d8..ac5e7f64c05c 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -161,11 +161,25 @@ static void print_vm_layout(void) { } void __init mem_init(void) { + bool swiotlb = max_pfn > PFN_DOWN(dma32_phys_limit); #ifdef CONFIG_FLATMEM BUG_ON(!mem_map); #endif /* CONFIG_FLATMEM */ - swiotlb_init(max_pfn > PFN_DOWN(dma32_phys_limit), SWIOTLB_VERBOSE); + if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && !swiotlb && + dma_cache_alignment != 1) { + /* + * If no bouncing needed for ZONE_DMA, allocate 1MB swiotlb + * buffer per 1GB of RAM for kmalloc() bouncing on + * non-coherent platforms. + */ + unsigned long size = + DIV_ROUND_UP(memblock_phys_mem_size(), 1024); + swiotlb_adjust_size(min(swiotlb_size_or_default(), size)); + swiotlb = true; + } + + swiotlb_init(swiotlb, SWIOTLB_VERBOSE); memblock_free_all(); print_vm_layout();
After commit f51f7a0fc2f4 ("riscv: enable DMA_BOUNCE_UNALIGNED_KMALLOC for !dma_coherent"), for non-coherent platforms with less than 4GB memory, we rely on users to pass "swiotlb=mmnn,force" kernel parameters to enable DMA bouncing for unaligned kmalloc() buffers. Now let's go further: If no bouncing needed for ZONE_DMA, let kernel automatically allocate 1MB swiotlb buffer per 1GB of RAM for kmalloc() bouncing on non-coherent platforms, so that no need to pass "swiotlb=mmnn,force" any more. The math of "1MB swiotlb buffer per 1GB of RAM for kmalloc() bouncing" is taken from arm64. Users can still force smaller swiotlb buffer by passing "swiotlb=mmnn". Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> --- since v2: - rebase on v6.8-rc1 - collect Reviewed-by tag since v1 - fix build error if CONFIG_RISCV_DMA_NONCOHERENT=n arch/riscv/include/asm/cache.h | 2 +- arch/riscv/mm/init.c | 16 +++++++++++++++- 2 files changed, 16 insertions(+), 2 deletions(-)