lkml.org 
[lkml]   [2013]   [May]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH net] sfc: Reduce RX scatter buffer size to multiple of 256
From
Hi Ben,

On Mon, May 13, 2013 at 7:48 PM, Ben Hutchings
<bhutchings@solarflare.com> 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@linux-m68k.org>
> Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
> Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
> ---
> 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

> failure - I don't have an s390 toolchain.

http://kernel.org/pub/tools/crosstool/files/bin/

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds


\
 
 \ /
  Last update: 2013-05-13 21:41    [W:0.054 / U:0.824 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site