On 15/02/19 9:20 PM, Faiz Abbas wrote: > sdhci.c has two bottom halves implemented. A threaded_irq for handling > card insert/remove operations and a tasklet for finishing mmc requests. > With the addition of external dma support, dmaengine APIs need to > terminate in non-atomic context before unmapping the dma buffers. > > To facilitate this, remove the finish_tasklet and move the call of > sdhci_request_done() to the threaded_irq() callback.
The irq thread has a higher latency than the tasklet. The performance drop is measurable on the system I tried: Before: # dd if=/dev/mmcblk1 of=/dev/null bs=1G count=1 & 1+0 records in 1+0 records out 1073741824 bytes (1.1 GB) copied, 4.44502 s, 242 MB/s After: # dd if=/dev/mmcblk1 of=/dev/null bs=1G count=1 & 1+0 records in 1+0 records out 1073741824 bytes (1.1 GB) copied, 4.50898 s, 238 MB/s So we only want to resort to the thread for the error case.
