The atomic DMA pools can dynamically expand based on non-blocking allocations that need to use it.
Export the sizes of each of these pools, in bytes, through debugfs for measurement. Suggested-by: Christoph Hellwig <h...@lst.de> Signed-off-by: David Rientjes <rient...@google.com> --- kernel/dma/pool.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c index cf052314d9e4..3e22022c933b 100644 --- a/kernel/dma/pool.c +++ b/kernel/dma/pool.c @@ -2,6 +2,7 @@ /* * Copyright (C) 2020 Google LLC */ +#include <linux/debugfs.h> #include <linux/dma-direct.h> #include <linux/dma-noncoherent.h> #include <linux/dma-contiguous.h> @@ -15,6 +16,11 @@ static struct gen_pool *atomic_pool_dma __ro_after_init; static struct gen_pool *atomic_pool_dma32 __ro_after_init; static struct gen_pool *atomic_pool_kernel __ro_after_init; +#ifdef CONFIG_DEBUG_FS +static unsigned long pool_size_dma; +static unsigned long pool_size_dma32; +static unsigned long pool_size_kernel; +#endif #define DEFAULT_DMA_COHERENT_POOL_SIZE SZ_256K static size_t atomic_pool_size = DEFAULT_DMA_COHERENT_POOL_SIZE; @@ -29,6 +35,38 @@ static int __init early_coherent_pool(char *p) } early_param("coherent_pool", early_coherent_pool); +#ifdef CONFIG_DEBUG_FS +static void __init dma_atomic_pool_debugfs_init(void) +{ + struct dentry *root; + + root = debugfs_create_dir("dma_pools", NULL); + if (IS_ERR_OR_NULL(root)) + return; + + debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma); + debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32); + debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel); +} + +static void dma_atomic_pool_size_add(gfp_t gfp, size_t size) +{ + if (gfp & __GFP_DMA) + pool_size_dma += size; + else if (gfp & __GFP_DMA32) + pool_size_dma32 += size; + else + pool_size_kernel += size; +} +#else +static inline void dma_atomic_pool_debugfs_init(void) +{ +} +static inline void dma_atomic_pool_size_add(gfp_t gfp, size_t size) +{ +} +#endif /* CONFIG_DEBUG_FS */ + static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, gfp_t gfp) { @@ -76,6 +114,7 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, if (ret) goto encrypt_mapping; + dma_atomic_pool_size_add(gfp, pool_size); return 0; encrypt_mapping: @@ -160,6 +199,8 @@ static int __init dma_atomic_pool_init(void) if (!atomic_pool_dma32) ret = -ENOMEM; } + + dma_atomic_pool_debugfs_init(); return ret; } postcore_initcall(dma_atomic_pool_init); _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu