On 5/31/23 17:48, Catalin Marinas wrote:
> Do not create kmalloc() caches which are not aligned to
> dma_get_cache_alignment(). There is no functional change since for
> current architectures defining ARCH_DMA_MINALIGN, ARCH_KMALLOC_MINALIGN
> equals ARCH_DMA_MINALIGN (and dma_get_cache_alignment()). On
> architectures without a specific ARCH_DMA_MINALIGN,
> dma_get_cache_alignment() is 1, so no change to the kmalloc() caches.
>
> If an architecture selects ARCH_HAS_DMA_CACHE_LINE_SIZE (introduced
> previously), the kmalloc() caches will be aligned to a cache line size.
It this part leftover from a previous version?
> Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Robin Murphy <robin.murphy@xxxxxxx>
Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
> ---
> mm/slab_common.c | 24 +++++++++++++++++++++---
> 1 file changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 7f069159aee2..7c6475847fdf 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -17,6 +17,7 @@
> #include <linux/cpu.h>
> #include <linux/uaccess.h>
> #include <linux/seq_file.h>
> +#include <linux/dma-mapping.h>
> #include <linux/proc_fs.h>
> #include <linux/debugfs.h>
> #include <linux/kasan.h>
> @@ -862,9 +863,18 @@ void __init setup_kmalloc_cache_index_table(void)
> }
> }
>
> +static unsigned int __kmalloc_minalign(void)
> +{
> + return dma_get_cache_alignment();
> +}
> +
> void __init
> new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
> {
> + unsigned int minalign = __kmalloc_minalign();
> + unsigned int aligned_size = kmalloc_info[idx].size;
> + int aligned_idx = idx;
> +
> if ((KMALLOC_RECLAIM != KMALLOC_NORMAL) && (type == KMALLOC_RECLAIM)) {
> flags |= SLAB_RECLAIM_ACCOUNT;
> } else if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_CGROUP)) {
> @@ -877,9 +887,17 @@ new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
> flags |= SLAB_CACHE_DMA;
> }
>
> - kmalloc_caches[type][idx] = create_kmalloc_cache(
> - kmalloc_info[idx].name[type],
> - kmalloc_info[idx].size, flags);
> + if (minalign > ARCH_KMALLOC_MINALIGN) {
> + aligned_size = ALIGN(aligned_size, minalign);
> + aligned_idx = __kmalloc_index(aligned_size, false);
> + }
> +
> + if (!kmalloc_caches[type][aligned_idx])
> + kmalloc_caches[type][aligned_idx] = create_kmalloc_cache(
> + kmalloc_info[aligned_idx].name[type],
> + aligned_size, flags);
> + if (idx != aligned_idx)
> + kmalloc_caches[type][idx] = kmalloc_caches[type][aligned_idx];
>
> /*
> * If CONFIG_MEMCG_KMEM is enabled, disable cache merging for
>
