Christoph, Alan,
> If it is allocating / freeing this memory all the time in the hot path
> it should really use a dma pool (see include/ilinux/dmapool.h).
> The dma coherent APIs aren't really built for being called in the
> hot path.
hcd_buffer_free uses a combination of dma pools and dma coherent APIs:
...
for (i = 0; i < HCD_BUFFER_POOLS; i++) {
if (size <= pool_max[i]) {
dma_pool_free(hcd->pool[i], addr, dma);
return;
}
}
dma_free_coherent(hcd->self.sysdev, size, addr, dma);
Alan, can dma_free_coherent be delayed to a point when IRQs are enabled?
[ Links to previous messages on this topic are listed below. ]
Fredrik
https://www.spinics.net/lists/linux-usb/msg162817.html
https://lists.linuxfoundation.org/pipermail/iommu/2018-March/026334.html
https://lists.linuxfoundation.org/pipermail/iommu/2018-March/026335.html
https://lists.linuxfoundation.org/pipermail/iommu/2018-March/026336.html
https://lists.linuxfoundation.org/pipermail/iommu/2018-March/026337.html
https://lists.linuxfoundation.org/pipermail/iommu/2018-March/026338.html
https://lists.linuxfoundation.org/pipermail/iommu/2018-March/026339.html
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