Hi Sedat,
On Sun, Apr 17, 2011 at 12:27:58AM +0800, Sedat Dilek wrote:
> I pulled your tree into linux-next (next-20110415) on an i386 Debian host.
>
> My build breaks here:
> ...
> MODPOST vmlinux.o
> GEN .version
> CHK include/generated/compile.h
> UPD include/generated/compile.h
> CC init/version.o
> LD init/built-in.o
> LD .tmp_vmlinux1
> mm/built-in.o: In function `bdi_position_ratio':
> page-writeback.c:(.text+0x5c83): undefined reference to `__udivdi3'
Yes it can be fixed by the attached patch.
> mm/built-in.o: In function `calc_period_shift.part.10':
> page-writeback.c:(.text+0x6446): undefined reference to `____ilog2_NaN'
I cannot reproduce this error. In the git tree, calc_period_shift() is
actually quite simple:
static int calc_period_shift(void)
{
return 2 + ilog2(default_backing_dev_info.avg_write_bandwidth);
}
where avg_write_bandwidth is of type "unsigned long".
> make[4]: *** [.tmp_vmlinux1] Error
>
> BTW, which kernel-config options have to be set besides
> CONFIG_BLK_DEV_THROTTLING=y?
No. I used your kconfig on 2.6.39-rc3 and it compiles OK for i386.
I've pushed two patches into the git tree fixing the compile errors.
Thank you for trying it out and report!
Thanks,
Fengguang
Subject: writeback: i386 compile fix
Date: Sun Apr 17 09:04:44 CST 2011
mm/built-in.o: In function `bdi_position_ratio':
page-writeback.c:(.text+0x5c83): undefined reference to `__udivdi3'
mm/built-in.o: In function `calc_period_shift.part.10':
page-writeback.c:(.text+0x6446): undefined reference to `____ilog2_NaN'
make[4]: *** [.tmp_vmlinux1] Error
Reported-by: Sedat Dilek <sedat.dilek@xxxxxxxxxxxxxx>
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
---
mm/page-writeback.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- linux-next.orig/mm/page-writeback.c 2011-04-17 09:02:32.000000000 +0800
+++ linux-next/mm/page-writeback.c 2011-04-17 09:03:58.000000000 +0800
@@ -634,9 +634,10 @@ static unsigned long bdi_position_ratio(
origin = bdi->avg_write_bandwidth + 2 * MIN_WRITEBACK_PAGES;
origin = min(origin, thresh - thresh / DIRTY_FULL_SCOPE);
if (bdi_dirty < origin) {
- if (bdi_dirty > origin / 4)
- bw = bw * origin / bdi_dirty;
- else
+ if (bdi_dirty > origin / 4) {
+ bw *= origin;
+ do_div(bw, bdi_dirty);
+ } else
bw = bw * 4;
}