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
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