Hi, On Fri, Mar 18, 2016 at 08:59:48AM +0200, Felipe Balbi wrote: > > Hi, > > Bin Liu <binmlist@xxxxxxxxx> writes: > > [ text/plain ] > > Hi, > > > > On Fri, Mar 11, 2016 at 6:54 AM, Felipe Balbi > > <felipe.balbi@xxxxxxxxxxxxxxx> wrote: > >> previously we were using a maximum of 32 TRBs per > >> endpoint. With each TRB being 16 bytes long, we were > >> using 512 bytes of memory for each endpoint. > >> > >> However, SLAB/SLUB will always allocate PAGE_SIZE > >> chunks. In order to better utilize the memory we > >> allocate and to allow deeper queues for gadgets > >> which would benefit from it (g_ether comes to mind), > >> let's increase the maximum to 256 TRBs which rounds > >> up to 4096 bytes for each endpoint. > > > > Do we want to increase the same for event ring buffers as > > while, which is allocated by dma_alloc_coherent(), which > > is also at PAGE_SIZE chunks, right? > > I could, but that's much less important. Currently we have up to 2 I agree it is less important, the only issue I see is wasting of memory. The device I am working on right now has two dwc3 controllers, each allocates 16 event buffers, so for the total of 128KB allocated pages, only 8KB is really used, 120KB is wasted. Seems dma pool makes more sense in here? Regards, -Bin. -- 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
