Re: Suspicious error for CMA stress test

From	Joonsoo Kim <iamjoonsoo.kim@lge.com>
Newsgroups	linux.kernel
Subject	Re: Suspicious error for CMA stress test
Date	2016-03-17 08:00 +0100
Message-ID	<rdA4y-3K4-3@gated-at.bofh.it> (permalink)
References	(5 earlier) <rbyJz-11y-1@gated-at.bofh.it> <rcuue-8R-19@gated-at.bofh.it> <rcuNz-ve-3@gated-at.bofh.it> <rcuXf-yJ-1@gated-at.bofh.it> <rdgfv-7bg-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed, Mar 16, 2016 at 05:44:28PM +0800, Hanjun Guo wrote:
> On 2016/3/14 15:18, Joonsoo Kim wrote:
> > On Mon, Mar 14, 2016 at 08:06:16AM +0100, Vlastimil Babka wrote:
> >> On 03/14/2016 07:49 AM, Joonsoo Kim wrote:
> >>> On Fri, Mar 11, 2016 at 06:07:40PM +0100, Vlastimil Babka wrote:
> >>>> On 03/11/2016 04:00 PM, Joonsoo Kim wrote:
> >>>>
> >>>> How about something like this? Just and idea, probably buggy (off-by-one etc.).
> >>>> Should keep away cost from <pageblock_order iterations at the expense of the
> >>>> relatively fewer >pageblock_order iterations.
> >>> Hmm... I tested this and found that it's code size is a little bit
> >>> larger than mine. I'm not sure why this happens exactly but I guess it would be
> >>> related to compiler optimization. In this case, I'm in favor of my
> >>> implementation because it looks like well abstraction. It adds one
> >>> unlikely branch to the merge loop but compiler would optimize it to
> >>> check it once.
> >> I would be surprised if compiler optimized that to check it once, as
> >> order increases with each loop iteration. But maybe it's smart
> >> enough to do something like I did by hand? Guess I'll check the
> >> disassembly.
> > Okay. I used following slightly optimized version and I need to
> > add 'max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1)'
> > to yours. Please consider it, too.
> 
> Hmm, this one is not work, I still can see the bug is there after applying
> this patch, did I miss something?

I may find that there is a bug which was introduced by me some time
ago. Could you test following change in __free_one_page() on top of
Vlastimil's patch?

-page_idx = pfn & ((1 << max_order) - 1);
+page_idx = pfn & ((1 << MAX_ORDER) - 1);

Thanks.

Thread

Re: Suspicious error for CMA stress test Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-03-07 05:40 +0100
  Re: Suspicious error for CMA stress test "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com> - 2016-03-07 09:20 +0100
    Re: Suspicious error for CMA stress test Laura Abbott <labbott@redhat.com> - 2016-03-07 19:50 +0100
      Re: Suspicious error for CMA stress test "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com> - 2016-03-08 03:00 +0100
        Re: Suspicious error for CMA stress test "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com> - 2016-03-09 02:30 +0100
          Re: Suspicious error for CMA stress test Joonsoo Kim <js1304@gmail.com> - 2016-03-11 16:10 +0100
            Re: Suspicious error for CMA stress test Vlastimil Babka <vbabka@suse.cz> - 2016-03-11 18:10 +0100
              Re: Suspicious error for CMA stress test Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-03-14 07:50 +0100
                Re: Suspicious error for CMA stress test Vlastimil Babka <vbabka@suse.cz> - 2016-03-14 08:10 +0100
                Re: Suspicious error for CMA stress test Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-03-14 08:20 +0100
                Re: Suspicious error for CMA stress test Vlastimil Babka <vbabka@suse.cz> - 2016-03-14 13:40 +0100
                Re: Suspicious error for CMA stress test Joonsoo Kim <js1304@gmail.com> - 2016-03-14 15:20 +0100
                Re: Suspicious error for CMA stress test Vlastimil Babka <vbabka@suse.cz> - 2016-03-16 13:10 +0100
                Re: Suspicious error for CMA stress test Hanjun Guo <guohanjun@huawei.com> - 2016-03-16 10:50 +0100
                Re: Suspicious error for CMA stress test Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-03-17 08:00 +0100
                Re: Suspicious error for CMA stress test Hanjun Guo <guohanjun@huawei.com> - 2016-03-17 10:30 +0100
                Re: Suspicious error for CMA stress test Joonsoo Kim <js1304@gmail.com> - 2016-03-17 16:40 +0100
                Re: Suspicious error for CMA stress test Hanjun Guo <guohanjun@huawei.com> - 2016-03-18 03:20 +0100
                Re: Suspicious error for CMA stress test Vlastimil Babka <vbabka@suse.cz> - 2016-03-17 16:50 +0100
                Re: Suspicious error for CMA stress test Joonsoo Kim <js1304@gmail.com> - 2016-03-17 17:00 +0100
                Re: Suspicious error for CMA stress test Lucas Stach <l.stach@pengutronix.de> - 2016-03-18 14:40 +0100
                Re: Suspicious error for CMA stress test Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-03-21 05:50 +0100
                Re: Suspicious error for CMA stress test Lucas Stach <l.stach@pengutronix.de> - 2016-03-22 16:00 +0100
                Re: Suspicious error for CMA stress test Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-03-23 05:50 +0100
                Re: Suspicious error for CMA stress test Vlastimil Babka <vbabka@suse.cz> - 2016-03-18 15:20 +0100
                Re: Suspicious error for CMA stress test Lucas Stach <l.stach@pengutronix.de> - 2016-03-18 15:50 +0100
                Re: Suspicious error for CMA stress test Vlastimil Babka <vbabka@suse.cz> - 2016-03-18 22:00 +0100
                Re: Suspicious error for CMA stress test Lucas Stach <l.stach@pengutronix.de> - 2016-03-22 15:50 +0100
                Re: Suspicious error for CMA stress test Hanjun Guo <guohanjun@huawei.com> - 2016-03-19 08:30 +0100
                Re: Suspicious error for CMA stress test Vlastimil Babka <vbabka@suse.cz> - 2016-03-19 23:20 +0100
                Re: Suspicious error for CMA stress test Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-03-23 05:50 +0100
                Re: Suspicious error for CMA stress test Vlastimil Babka <vbabka@suse.cz> - 2016-03-23 09:30 +0100
                Re: Suspicious error for CMA stress test Joonsoo Kim <js1304@gmail.com> - 2016-03-23 09:40 +0100
                Re: Suspicious error for CMA stress test Vlastimil Babka <vbabka@suse.cz> - 2016-03-18 13:30 +0100
    Re: Suspicious error for CMA stress test Hanjun Guo <hanjun.guo@linaro.org> - 2016-03-08 05:10 +0100
  Re: Suspicious error for CMA stress test Vlastimil Babka <vbabka@suse.cz> - 2016-03-07 14:00 +0100
    Re: Suspicious error for CMA stress test Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-03-08 08:50 +0100
      Re: Suspicious error for CMA stress test Xishi Qiu <qiuxishi@huawei.com> - 2016-03-08 11:50 +0100
        Re: Suspicious error for CMA stress test Joonsoo Kim <js1304@gmail.com> - 2016-03-08 16:40 +0100
          Re: Suspicious error for CMA stress test Xishi Qiu <qiuxishi@huawei.com> - 2016-03-09 03:20 +0100

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