From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755152Ab0I1UQa (ORCPT ); Tue, 28 Sep 2010 16:16:30 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:45033 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752959Ab0I1UQ3 (ORCPT ); Tue, 28 Sep 2010 16:16:29 -0400 Message-ID: <4CA24CD9.8090202@oracle.com> Date: Tue, 28 Sep 2010 13:15:21 -0700 From: Randy Dunlap Organization: Oracle Linux Engineering User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.5) Gecko/20091209 Fedora/3.0-3.fc11 Thunderbird/3.0 MIME-Version: 1.0 To: Vivek Goyal CC: linux kernel mailing list , Jens Axboe Subject: Re: [PATCH] blkio-throttle: Fix linux-next compilation failure on i386 References: <20100928193446.GE8950@redhat.com> In-Reply-To: <20100928193446.GE8950@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/28/10 12:34, Vivek Goyal wrote: > Hi Jens, > > One more fix for throttling logic. After this fix I realized that there is > potential for integer overflow in my calculations. I need to figure out > how to take care of these overflow situations and will post a patch for > that later. > > Thanks > Vivek > > o Randy Dunlap reported following linux-next failure. This patch fixes it. > > on i386: > > blk-throttle.c:(.text+0x1abb8): undefined reference to `__udivdi3' > blk-throttle.c:(.text+0x1b1dc): undefined reference to `__udivdi3' > > o bytes_per_second interface is 64bit and I was continuing to do 64 bit > division even on 32bit platform without help of special macros/functions > hence the failure. > > Signed-off-by: Vivek Goyal Acked-by: Randy Dunlap Thanks. > --- > block/blk-throttle.c | 16 ++++++++++------ > 1 file changed, 10 insertions(+), 6 deletions(-) > > Index: linux-2.6-block/block/blk-throttle.c > =================================================================== > --- linux-2.6-block.orig/block/blk-throttle.c 2010-09-28 12:42:51.000000000 -0400 > +++ linux-2.6-block/block/blk-throttle.c 2010-09-28 14:16:05.000000000 -0400 > @@ -378,7 +378,8 @@ throtl_slice_used(struct throtl_data *td > static inline void > throtl_trim_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw) > { > - unsigned long nr_slices, bytes_trim, time_elapsed, io_trim; > + unsigned long nr_slices, time_elapsed, io_trim; > + u64 bytes_trim, tmp; > > BUG_ON(time_before(tg->slice_end[rw], tg->slice_start[rw])); > > @@ -396,8 +397,10 @@ throtl_trim_slice(struct throtl_data *td > > if (!nr_slices) > return; > + tmp = tg->bps[rw] * throtl_slice * nr_slices; > + do_div(tmp, HZ); > + bytes_trim = tmp; > > - bytes_trim = (tg->bps[rw] * throtl_slice * nr_slices)/HZ; > io_trim = (tg->iops[rw] * throtl_slice * nr_slices)/HZ; > > if (!bytes_trim && !io_trim) > @@ -415,7 +418,7 @@ throtl_trim_slice(struct throtl_data *td > > tg->slice_start[rw] += nr_slices * throtl_slice; > > - throtl_log_tg(td, tg, "[%c] trim slice nr=%lu bytes=%lu io=%lu" > + throtl_log_tg(td, tg, "[%c] trim slice nr=%lu bytes=%llu io=%lu" > " start=%lu end=%lu jiffies=%lu", > rw == READ ? 'R' : 'W', nr_slices, bytes_trim, io_trim, > tg->slice_start[rw], tg->slice_end[rw], jiffies); > @@ -462,7 +465,7 @@ static bool tg_with_in_bps_limit(struct > struct bio *bio, unsigned long *wait) > { > bool rw = bio_data_dir(bio); > - u64 bytes_allowed, extra_bytes; > + u64 bytes_allowed, extra_bytes, tmp; > unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; > > jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw]; > @@ -473,8 +476,9 @@ static bool tg_with_in_bps_limit(struct > > jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, throtl_slice); > > - bytes_allowed = (tg->bps[rw] * jiffies_to_msecs(jiffy_elapsed_rnd)) > - / MSEC_PER_SEC; > + tmp = tg->bps[rw] * jiffies_to_msecs(jiffy_elapsed_rnd); > + do_div(tmp, MSEC_PER_SEC); > + bytes_allowed = tmp; > > if (tg->bytes_disp[rw] + bio->bi_size <= bytes_allowed) { > if (wait) -- ~Randy *** Remember to use Documentation/SubmitChecklist when testing your code ***