On Mon, 2013-05-13 at 21:02 +0200, Geert Uytterhoeven wrote: > Hi Ben, > > On Mon, May 13, 2013 at 7:48 PM, Ben Hutchings > <bhutchings@xxxxxxxxxxxxxx> wrote: > > efx_start_datapath() asserts that we can fit 2 RX scatter buffers plus > > a software structure, each cache-aligned, into a single page. Where > > L1_CACHE_BYTES == 256 and PAGE_SIZE == 4096, which is the case on > > s390, this assertion fails. Reduce EFX_RX_USR_BUF_SIZE to make this > > work. > > > > This should also be good for performance, as it ensures that each RX > > scatter buffer covers whole cache lines and slightly reduces the use > > of DMA writes that can require a read-modify-write on inter-processor > > links. > > > > (We could use 2048 - L1_CACHE_BYTES, but EFX_RX_USR_BUF_SIZE also > > affects user-level networking where a larger amount of housekeeping > > data may be needed. Although this version of the driver does not > > support user-level networking, I prefer to keep scattering behaviour > > consistent with the out-of-tree version.) > > > > Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> > > Reported-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx> > > Signed-off-by: Ben Hutchings <bhutchings@xxxxxxxxxxxxxx> > > --- > > Heiko or Geert, please confirm that this really does fix the build > > Thanks! But unfortunately I still get the same error: > > CC [M] drivers/net/ethernet/sfc/efx.o > /scratch/geert/linux/linux-m68k/drivers/net/ethernet/sfc/efx.c: In > function 'efx_start_datapath': > /scratch/geert/linux/linux-m68k/drivers/net/ethernet/sfc/efx.c:646:3: > error: call to '__compiletime_assert_648' declared with attribute > error: BUILD_BUG_ON failed: sizeof(struct efx_rx_page_state) + > EFX_PAGE_IP_ALIGN + EFX_RX_USR_BUF_SIZE > PAGE_SIZE / 2 > make[4]: *** [drivers/net/ethernet/sfc/efx.o] Error 1 OK, this doesn't work because on s390 EFX_PAGE_IP_ALIGN == 2 (this macro is equivalent to NET_IP_ALIGN, though that wasn't always true). So DMA is going to be misaligned on s390 anyway. I'll see if I can work out a sensible definition that works for s390 while still being good for x86 and powerpc (which are the two we mostly care about). > > failure - I don't have an s390 toolchain. > > http://kernel.org/pub/tools/crosstool/files/bin/ I know, but this still takes time to set up. Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked. -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
