From 02e765697038c596dc4a1126a13b018608365d81 Mon Sep 17 00:00:00 2001 From: ZhangPeng Date: Tue, 9 Jan 2024 15:04:56 +0800 Subject: swiotlb: add debugfs to track swiotlb transient pool usage Introduce a new debugfs interface io_tlb_transient_nslabs. The device driver can create a new swiotlb transient memory pool once default memory pool is full. To export the swiotlb transient memory pool usage via debugfs would help the user estimate the size of transient swiotlb memory pool or analyze device driver memory leak issue. Signed-off-by: ZhangPeng Signed-off-by: Christoph Hellwig --- kernel/dma/swiotlb.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) (limited to 'kernel/dma/swiotlb.c') diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index b079a9a8e087..77974cea3e69 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -956,6 +956,28 @@ static void dec_used(struct io_tlb_mem *mem, unsigned int nslots) } #endif /* CONFIG_DEBUG_FS */ +#ifdef CONFIG_SWIOTLB_DYNAMIC +#ifdef CONFIG_DEBUG_FS +static void inc_transient_used(struct io_tlb_mem *mem, unsigned int nslots) +{ + atomic_long_add(nslots, &mem->transient_nslabs); +} + +static void dec_transient_used(struct io_tlb_mem *mem, unsigned int nslots) +{ + atomic_long_sub(nslots, &mem->transient_nslabs); +} + +#else /* !CONFIG_DEBUG_FS */ +static void inc_transient_used(struct io_tlb_mem *mem, unsigned int nslots) +{ +} +static void dec_transient_used(struct io_tlb_mem *mem, unsigned int nslots) +{ +} +#endif /* CONFIG_DEBUG_FS */ +#endif /* CONFIG_SWIOTLB_DYNAMIC */ + /** * swiotlb_search_pool_area() - search one memory area in one pool * @dev: Device which maps the buffer. @@ -1170,6 +1192,7 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr, spin_lock_irqsave(&dev->dma_io_tlb_lock, flags); list_add_rcu(&pool->node, &dev->dma_io_tlb_pools); spin_unlock_irqrestore(&dev->dma_io_tlb_lock, flags); + inc_transient_used(mem, pool->nslabs); found: WRITE_ONCE(dev->dma_uses_io_tlb, true); @@ -1415,6 +1438,7 @@ static bool swiotlb_del_transient(struct device *dev, phys_addr_t tlb_addr) dec_used(dev->dma_io_tlb_mem, pool->nslabs); swiotlb_del_pool(dev, pool); + dec_transient_used(dev->dma_io_tlb_mem, pool->nslabs); return true; } @@ -1557,6 +1581,23 @@ phys_addr_t default_swiotlb_limit(void) } #ifdef CONFIG_DEBUG_FS +#ifdef CONFIG_SWIOTLB_DYNAMIC +static unsigned long mem_transient_used(struct io_tlb_mem *mem) +{ + return atomic_long_read(&mem->transient_nslabs); +} + +static int io_tlb_transient_used_get(void *data, u64 *val) +{ + struct io_tlb_mem *mem = data; + + *val = mem_transient_used(mem); + return 0; +} + +DEFINE_DEBUGFS_ATTRIBUTE(fops_io_tlb_transient_used, io_tlb_transient_used_get, + NULL, "%llu\n"); +#endif /* CONFIG_SWIOTLB_DYNAMIC */ static int io_tlb_used_get(void *data, u64 *val) { @@ -1605,6 +1646,11 @@ static void swiotlb_create_debugfs_files(struct io_tlb_mem *mem, &fops_io_tlb_used); debugfs_create_file("io_tlb_used_hiwater", 0600, mem->debugfs, mem, &fops_io_tlb_hiwater); +#ifdef CONFIG_SWIOTLB_DYNAMIC + atomic_long_set(&mem->transient_nslabs, 0); + debugfs_create_file("io_tlb_transient_nslabs", 0400, mem->debugfs, + mem, &fops_io_tlb_transient_used); +#endif } static int __init swiotlb_create_default_debugfs(void) -- cgit v1.2.3