On Mon 05-08-19 19:57:54, Fuqian Huang wrote: > In the implementation of kmalloc. > when the allocated size is larger than KMALLOC_MAX_CACHE_SIZE, > it will call kmalloc_large to allocate the memory. > kmalloc_large -> > kmalloc_order_trace->kmalloc_order->alloc_pages->alloc_pages_current->alloc_pages_nodemask->get_page_from_freelist->node_reclaim->__node_reclaim->shrink_node->shrink_node_memcg->get_scan_count
You shouldn't really get there when using GFP_NOWAIT/GFP_ATOMIC. > get_scan_count will call spin_unlock_irq which enables local interrupt. > As the local interrupt should be disabled in the interrupt handler. > It is safe to use kmalloc to allocate a large size of memory in > interrupt handler? It will work very unreliably because larger physically contiguous memory is not generally available without doing compaction after a longer runtime. In general I would recommend to use pre allocated buffers or defer the actual handling to a less restricted context if possible. -- Michal Hocko SUSE Labs
