On 19 December 2015 at 21:30, Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> wrote: > Unnecessarily mapping and unmapping the align buffer for SD cards is > expensive: performance measurements on iMX6 show that this gives a hit > of 10% on hdparm buffered disk reads. > > MMC/SD card IO comes from the mm/vfs which gives us page based IO, so > for this case, the align buffer is not going to be used. However, we > still map and unmap this buffer. What about the SDIO case? How will this change affect SDIO data transfers? > > Eliminate this by switching the align buffer to be a DMA coherent > buffer, which needs no DMA maintanence to access the buffer. /s/maintanence/maintenance [...] Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
