在 2020/7/10 下午1:28, Mika Penttilä 写道: >> Thanks a lot for quick reply! >> What I am confusing is the call chain: __iommu_dma_alloc_pages() >> to split_huge_page(), in the func, splited page, >> page = alloc_pages_node(nid, alloc_flags, order); >> And if the pages were added into lru, they maybe reclaimed and lost, >> that would be a panic bug. But in fact, this never happened for long time. >> Also I put a BUG() at the line, it's nevre triggered in ltp, and run_vmtests > > In __iommu_dma_alloc_pages, after split_huge_page(), who is taking a > reference on tail pages? Seems tail pages are freed and the function > errornously returns them in pages[] array for use? > Why you say so? It looks like the tail page returned and be used pages = __iommu_dma_alloc_pages() in iommu_dma_alloc_remap() and still on node's lru. Is this right? thanks!
