On Mon, Mar 25, 2019 at 04:37:09PM +0800, Peter Chen wrote: > Hi Michal & Marek, > > I meet an issue that the DMA (CMA used) allocation failed if there is a user > signal, Eg Ctrl+C, it causes the USB xHCI stack fails to resume due to > dma_alloc_coherent > failed. It can be easy to reproduce if the user press Ctrl+C at > suspend/resume test. It has been possible in the past for cma_alloc() to take seconds or longer to allocate, depending on the size of the CMA area and the number of pinned GFP_MOVABLE pages within the CMA area. Whether that is true of today's CMA or not, I don't know. It's probably there to allow such a situation to be recoverable, but is not a good idea if we're expecting dma_alloc_*() not to fail in those scenarios. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up
