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 <[email protected]>
---
arch/riscv/mm/init.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 2e011cbddf3a..cbcb9918f721 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -162,11 +162,25 @@ 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();
--
2.42.0
Hi Jisheng,
kernel test robot noticed the following build errors:
[auto build test ERROR on linus/master]
[also build test ERROR on v6.7-rc2 next-20231124]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Jisheng-Zhang/riscv-mm-still-create-swiotlb-buffer-for-kmalloc-bouncing-if-required/20231127-014531
base: linus/master
patch link: https://lore.kernel.org/r/20231126162528.2411-1-jszhang%40kernel.org
patch subject: [PATCH] riscv: mm: still create swiotlb buffer for kmalloc() bouncing if required
config: riscv-allnoconfig (https://download.01.org/0day-ci/archive/20231127/[email protected]/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231127/[email protected]/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All errors (new ones prefixed by >>):
>> arch/riscv/mm/init.c:171:6: error: use of undeclared identifier 'dma_cache_alignment'; did you mean 'dma_get_cache_alignment'?
171 | dma_cache_alignment != 1) {
| ^~~~~~~~~~~~~~~~~~~
| dma_get_cache_alignment
include/linux/dma-mapping.h:541:19: note: 'dma_get_cache_alignment' declared here
541 | static inline int dma_get_cache_alignment(void)
| ^
1 error generated.
vim +171 arch/riscv/mm/init.c
169
170 if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && !swiotlb &&
> 171 dma_cache_alignment != 1) {
172 /*
173 * If no bouncing needed for ZONE_DMA, allocate 1MB swiotlb
174 * buffer per 1GB of RAM for kmalloc() bouncing on
175 * non-coherent platforms.
176 */
177 unsigned long size =
178 DIV_ROUND_UP(memblock_phys_mem_size(), 1024);
179 swiotlb_adjust_size(min(swiotlb_size_or_default(), size));
180 swiotlb = true;
181 }
182
183 swiotlb_init(swiotlb, SWIOTLB_VERBOSE);
184 memblock_free_all();
185
186 print_vm_layout();
187 }
188
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Hi Jisheng,
kernel test robot noticed the following build errors:
[auto build test ERROR on linus/master]
[also build test ERROR on v6.7-rc3 next-20231127]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Jisheng-Zhang/riscv-mm-still-create-swiotlb-buffer-for-kmalloc-bouncing-if-required/20231127-014531
base: linus/master
patch link: https://lore.kernel.org/r/20231126162528.2411-1-jszhang%40kernel.org
patch subject: [PATCH] riscv: mm: still create swiotlb buffer for kmalloc() bouncing if required
config: riscv-randconfig-002-20231127 (https://download.01.org/0day-ci/archive/20231127/[email protected]/config)
compiler: riscv64-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231127/[email protected]/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All errors (new ones prefixed by >>):
arch/riscv/mm/init.c: In function 'mem_init':
>> arch/riscv/mm/init.c:171:13: error: 'dma_cache_alignment' undeclared (first use in this function); did you mean 'dma_get_cache_alignment'?
171 | dma_cache_alignment != 1) {
| ^~~~~~~~~~~~~~~~~~~
| dma_get_cache_alignment
arch/riscv/mm/init.c:171:13: note: each undeclared identifier is reported only once for each function it appears in
vim +171 arch/riscv/mm/init.c
169
170 if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && !swiotlb &&
> 171 dma_cache_alignment != 1) {
172 /*
173 * If no bouncing needed for ZONE_DMA, allocate 1MB swiotlb
174 * buffer per 1GB of RAM for kmalloc() bouncing on
175 * non-coherent platforms.
176 */
177 unsigned long size =
178 DIV_ROUND_UP(memblock_phys_mem_size(), 1024);
179 swiotlb_adjust_size(min(swiotlb_size_or_default(), size));
180 swiotlb = true;
181 }
182
183 swiotlb_init(swiotlb, SWIOTLB_VERBOSE);
184 memblock_free_all();
185
186 print_vm_layout();
187 }
188
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki