Hi Alan, One Thousand Gnomes 於 2016/7/29 下午 08:48 寫道:
O+static int f81534_set_normal_register(struct usb_device *dev, u16 reg, u8 data) +{ + size_t count = F81534_USB_MAX_RETRY; + int status; + u8 *tmp; + + tmp = kmalloc(sizeof(u8), GFP_KERNEL); + if (!tmp) + return -ENOMEM;You end up doing huge numbers of tiny allocation and frees in some of the code paths. I think it would be better to allocate them at a higher level as they are not that cheap on CPU time.+static int f81534_read_data(struct usb_serial *usbserial, u32 address, + size_t size, unsigned char *buf) +{Is a particularly good example - you do 4 mallocs plus two per byte of data.
I'll re-factor the newest V9 patch with your suggestion. To malloc a byte within usb_serial privates, and make a mutex to protect it. I'll send it as V10 when I tested it. Thanks for your suggestion. -- With Best Regards, Peter Hong -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
