linux-kernel - Re: [PATCH 17/17] vsprintf: rework bitmap_list

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Message-ID: <YSgAmjvwscaRb8PT@yury-ThinkPad>
Date:   Thu, 26 Aug 2021 13:59:06 -0700
From:   Yury Norov <yury.norov@...il.com>
To:     Petr Mladek <pmladek@...e.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        linux-arch@...r.kernel.org, linux-kselftest@...r.kernel.org,
        linux-mmc@...r.kernel.org, linux-perf-users@...r.kernel.org,
        kvm@...r.kernel.org,
        "James E.J. Bottomley" <James.Bottomley@...senpartnership.com>,
        Alexander Lobakin <alobakin@...me>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Alexey Klimov <aklimov@...hat.com>,
        Andrea Merello <andrea.merello@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Arnd Bergmann <arnd@...db.de>, Ben Gardon <bgardon@...gle.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Brian Cain <bcain@...eaurora.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Christoph Lameter <cl@...ux.com>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        David Hildenbrand <david@...hat.com>,
        Dennis Zhou <dennis@...nel.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Ian Rogers <irogers@...gle.com>,
        Ingo Molnar <mingo@...hat.com>,
        Jaegeuk Kim <jaegeuk@...nel.org>,
        Jakub Kicinski <kuba@...nel.org>, Jiri Olsa <jolsa@...hat.com>,
        Joe Perches <joe@...ches.com>, Jonas Bonn <jonas@...thpole.se>,
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        Namhyung Kim <namhyung@...nel.org>,
        Palmer Dabbelt <palmer@...belt.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Peter Xu <peterx@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Rich Felker <dalias@...c.org>,
        Samuel Mendoza-Jonas <sam@...dozajonas.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Sergey Senozhatsky <senozhatsky@...omium.org>,
        Shuah Khan <shuah@...nel.org>,
        Stefan Kristiansson <stefan.kristiansson@...nalahti.fi>,
        Steven Rostedt <rostedt@...dmis.org>,
        Tejun Heo <tj@...nel.org>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Will Deacon <will@...nel.org>,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>
Subject: Re: [PATCH 17/17] vsprintf: rework bitmap_list_string

On Thu, Aug 26, 2021 at 04:15:09PM +0200, Petr Mladek wrote:
> On Sat 2021-08-14 14:17:13, Yury Norov wrote:
> > bitmap_list_string() is very ineffective when printing bitmaps with long
> > ranges of set bits because it calls find_next_bit for each bit in the
> > bitmap.  We can do better by detecting ranges of set bits.
> > 
> > In my environment, before/after is 943008/31008 ns.
> > 
> > Signed-off-by: Yury Norov <yury.norov@...il.com>
> > Tested-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
> 
> I like the patch. The new code is much easier to follow.
> Feel free to use:
> 
> Reviewed-by: Petr Mladek <pmladek@...e.com>
> 
> Best Regards,
> Petr

Thanks Petr! The patch is already in the linux-next.

Andrew, Stephen, can you please append Petr's reviewed-by?

Thanks,
Yury