> From: "Christopher Hoover" <[EMAIL PROTECTED]> > Date: Fri, 6 Jun 2003 10:58:50 -0700
> > So all I/O buffers _must_ be allocated using kmalloc() > > Use GFP_DMA flag on the kmalloc() call, too, whenever possible. > This will help avoid bounce buffering on some systems. Wrong!!! Where did you get this idiotic idea? NEVER use GFP_DMA if you can help it. It allocates from zone[0] and creates pressure on it. -- Pete P.S. For the record, GFP_DMA is needed when a device does not have enough addressing capability to reach normal memory _and_ there is no MMU in the picture. Thus, it's a short list: 1. Non-busmastering DMA for ISA devices on x86 2. CCW on s390 (but not IDALs) 3. SAC PCI DMA on Itanic with no MMU, such as SGI SN-2 This is _it_! No more cases to use GFP_DMA! ------------------------------------------------------- This SF.net email is sponsored by: Etnus, makers of TotalView, The best thread debugger on the planet. Designed with thread debugging features you've never dreamed of, try TotalView 6 free at www.etnus.com. _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
