On 7/2/07, Greg KH <[EMAIL PROTECTED]> wrote: > On Mon, Jul 02, 2007 at 03:36:37PM -0700, Yinghai Lu wrote: > > [PATCH 3/4] usb: allocated usb releated dma buffer with kmalloc_node > > > > For amd64 based two way system. USB always on node0. but dma buffer for urb > > allocated via kmalloc always get ram on node1. So change to kmalloc_node to > > get dma_buffer on corresponding node > > Are all of these changes really necessary? You are doing this for some > allocations that take a _long_ time when sending to the device due to > the speed of the device. > > I could possibly see this making a difference on some drivers, but for > the core, and for the basic USB structures, I can't imagine it is really > worth it. > > Or do you have numbers showing the differences here? > > Patch included fully below for the benifit of the usb list, which you > should have cc:ed...
dma buffer could be allocated via alloc_pages_coherent. or kmalloc/dma_map_single. alloc_pages_coherent get the dma_buffer on corresponding node. but kmalloc/dma_map_single always get dma_buffer on last node. or say device is on HT chain node0, it will get dma buffer on node 7 of 8 socket system. also on two way system with 4G+4G RAM conf. device on node 0 will get dma_buffer above 4G, and if the dma_mask is less 32bit, will need extra iommu mapping. In my mcp55+io55 system, it show dma_map_single is keepping called by usb input: keyboard/mouse (8/0x40 bytes), and forcedeth. (0x670bytes) YH ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
