Hi, Bin Liu <b-liu@xxxxxx> writes: > [ text/plain ] > Hi, > > On Wed, Mar 30, 2016 at 09:14:18AM +0300, Felipe Balbi wrote: >> >> Hi again, >> >> Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> writes: >> > Bin Liu <b-liu@xxxxxx> writes: >> >> 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? >> > >> > I don't know. I think the real thing is that I really need to revisit >> > that part of the code/databook. The whole "multiple interrupters" seems >> > like it's only really necessary for host side. Which means that we could >> > drop all the loops for multiple event buffers and always use a single >> > one. >> > >> > Do you wanna test the following ? >> > >> > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c >> > index 17fd81447c9f..ebb3ee9c06f1 100644 >> > --- a/drivers/usb/dwc3/core.c >> > +++ b/drivers/usb/dwc3/core.c >> > @@ -237,8 +237,7 @@ static int dwc3_alloc_event_buffers(struct dwc3 *dwc, unsigned length) >> > int num; >> > int i; >> > >> > - num = DWC3_NUM_INT(dwc->hwparams.hwparams1); >> > - dwc->num_event_buffers = num; >> > + dwc->num_event_buffers = 1; >> > >> > dwc->ev_buffs = devm_kzalloc(dwc->dev, sizeof(*dwc->ev_buffs) * num, >> > GFP_KERNEL); >> > >> > I'll re-read what these bits actually mean. I have a strong feeling we >> > could (should?) be ignoring them for the peripheral side. >> >> Okay, so when we're configuring the endpoints, we could route endpoint >> interrupts to different event buffers. I really think that's really >> unimportant for us, specially since we end up using a single IRQ line. >> >> I guess I'll just go ahead and remove that code. If it turns out we >> decide to use it, we shouldn't really be using a loop in the hardirq >> handler anyway. > > Sounds good to me, I only see one evt buffer is used in all my devices, > even thought multi buffers are allocated based on hwparams1. I sent some patches yesterday. You might wanna give it a review ;-) -- balbi
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