We observed the error "cacheline tracking ENOMEM, dma-debug disabled" during a light system load (copying some files). The reason for this error is that the dma_active_cacheline radix tree uses GFP_NOWAIT allocation - so it can't access the emergency memory reserves and it fails as soon as anybody reaches the watermark.
This patch changes GFP_NOWAIT to GFP_ATOMIC, so that it can access the emergency memory reserves. Signed-off-by: Mikulas Patocka <[email protected]> --- kernel/dma/debug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linux-2.6/kernel/dma/debug.c =================================================================== --- linux-2.6.orig/kernel/dma/debug.c 2022-03-30 14:39:00.000000000 +0200 +++ linux-2.6/kernel/dma/debug.c 2022-05-09 16:32:07.000000000 +0200 @@ -448,7 +448,7 @@ void debug_dma_dump_mappings(struct devi * other hand, consumes a single dma_debug_entry, but inserts 'nents' * entries into the tree. */ -static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT); +static RADIX_TREE(dma_active_cacheline, GFP_ATOMIC); static DEFINE_SPINLOCK(radix_lock); #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1) #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT) _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
