From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B733FC433ED for ; Thu, 1 Apr 2021 08:59:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 70812610A5 for ; Thu, 1 Apr 2021 08:59:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233637AbhDAI6f (ORCPT ); Thu, 1 Apr 2021 04:58:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59348 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233732AbhDAI62 (ORCPT ); Thu, 1 Apr 2021 04:58:28 -0400 Received: from mail-pl1-x62e.google.com (mail-pl1-x62e.google.com [IPv6:2607:f8b0:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC6B8C0613E6; Thu, 1 Apr 2021 01:58:26 -0700 (PDT) Received: by mail-pl1-x62e.google.com with SMTP id h20so694614plr.4; Thu, 01 Apr 2021 01:58:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dNcEUdL+Y2EFFIxydzK2lkO73+Grx7yUTd4+U1ZR2Co=; b=iepTEBY9UHxW4HJcHM3NpviYdGyMD0zHQy1yz3FTDDFpVHSlie5TVN2fqTwFoVmwXY s8hnEeMYsY1/vIIMf8gNvNHpKpz7nP+DdMLiZ10i8zV9QugSWJm3zBcReBIX/FcrEse3 wbVcqdJ95Fvl8ggf+nJgOpptWWaHk3Feyyp1t9En7lgS7mHxEGZ8sNL0xKHeJROmUL++ vA2FUfHy9qcFo4CCRB46y61NYmj/nBmEDcTW6TrBPzgAUxVH9dy9fyLJmWlCfPm4nqef PTh78fLB4zKNg2+LHreObaXnzKnloJdCbKa1laozju8t7ue+iv7zwJWwJFel1O+WnyEH kt4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=dNcEUdL+Y2EFFIxydzK2lkO73+Grx7yUTd4+U1ZR2Co=; b=bfvnfEoP2EcfjgqsFhm7pu5ghKx5X+62bYM8gEJkO2rnw95dqtFrJYxo/M35GPHVXs ajGemffbunBShHvMrKKzLjGjIKxCpMLz9UEtZR5d05bqKisnsuL9EzapDY/Z9rmFB6JX GRpocU7bnd6bxD42VdRkrQyDft6EpC4XPTQD0bcuLMYKsnnrTiy/Bs40hjSotl7QiQAt +KrIoImmOJfjyW+wkUW2goSKHy9EstnU2sh5oHUamifSEIgUJix2Won/VXHboeCpPmGj SfxnaYWAm/WmtM0KH2LAWZSv39wqejAKVqkIG5cEbJzTHDJUgHUsR84VbhLHOdgcXP8u Pcxg== X-Gm-Message-State: AOAM533wsPRkBE6B/77LGzvg+wFOnTDbishUn5wHlHZUP+sMjeVygZWM hFZoWgO29Q3KsSDb7s1oj0yXLKfmiSQcwPIZkPw= X-Google-Smtp-Source: ABdhPJzEzb75COZ6+ksiycIV+rVeckcELZI+Vey5LZL67pRGO8TjUwA3qD9uZ3Ar7unIpfcrYoM4GH6Fkky8CnYszPc= X-Received: by 2002:a17:90a:db49:: with SMTP id u9mr8124742pjx.181.1617267506376; Thu, 01 Apr 2021 01:58:26 -0700 (PDT) MIME-Version: 1.0 References: <20210401003153.97325-1-yury.norov@gmail.com> <20210401003153.97325-11-yury.norov@gmail.com> In-Reply-To: <20210401003153.97325-11-yury.norov@gmail.com> From: Andy Shevchenko Date: Thu, 1 Apr 2021 11:58:10 +0300 Message-ID: Subject: Re: [PATCH 10/12] lib: add fast path for find_first_*_bit() and find_last_bit() To: Yury Norov Cc: Linux Kernel Mailing List , Andrew Morton , linux-m68k , Linux-Arch , Linux-SH , Alexey Klimov , Andy Shevchenko , Arnd Bergmann , David Sterba , Dennis Zhou , Geert Uytterhoeven , Jianpeng Ma , Joe Perches , John Paul Adrian Glaubitz , Josh Poimboeuf , Rasmus Villemoes , Rich Felker , Stefano Brivio , Wei Yang , Wolfram Sang , Yoshinori Sato Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org On Thu, Apr 1, 2021 at 3:41 AM Yury Norov wrote: > > Similarly to bitmap functions, users would benefit if we'll handle > a case of small-size bitmaps that fit into a single word. > > While here, move the find_last_bit() declaration to bitops/find.h > where other find_*_bit() functions sit. Acked-by: Andy Shevchenko > Signed-off-by: Yury Norov > Acked-by: Rasmus Villemoes > --- > include/asm-generic/bitops/find.h | 50 ++++++++++++++++++++++++++++--- > include/linux/bitops.h | 12 -------- > lib/find_bit.c | 12 ++++---- > 3 files changed, 52 insertions(+), 22 deletions(-) > > diff --git a/include/asm-generic/bitops/find.h b/include/asm-generic/bitops/find.h > index 4148c74a1e4d..0d132ee2a291 100644 > --- a/include/asm-generic/bitops/find.h > +++ b/include/asm-generic/bitops/find.h > @@ -5,6 +5,9 @@ > extern unsigned long _find_next_bit(const unsigned long *addr1, > const unsigned long *addr2, unsigned long nbits, > unsigned long start, unsigned long invert, unsigned long le); > +extern unsigned long _find_first_bit(const unsigned long *addr, unsigned long size); > +extern unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size); > +extern unsigned long _find_last_bit(const unsigned long *addr, unsigned long size); > > #ifndef find_next_bit > /** > @@ -102,8 +105,17 @@ unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, > * Returns the bit number of the first set bit. > * If no bits are set, returns @size. > */ > -extern unsigned long find_first_bit(const unsigned long *addr, > - unsigned long size); > +static inline > +unsigned long find_first_bit(const unsigned long *addr, unsigned long size) > +{ > + if (small_const_nbits(size)) { > + unsigned long val = *addr & GENMASK(size - 1, 0); > + > + return val ? __ffs(val) : size; > + } > + > + return _find_first_bit(addr, size); > +} > > /** > * find_first_zero_bit - find the first cleared bit in a memory region > @@ -113,8 +125,17 @@ extern unsigned long find_first_bit(const unsigned long *addr, > * Returns the bit number of the first cleared bit. > * If no bits are zero, returns @size. > */ > -extern unsigned long find_first_zero_bit(const unsigned long *addr, > - unsigned long size); > +static inline > +unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size) > +{ > + if (small_const_nbits(size)) { > + unsigned long val = *addr | ~GENMASK(size - 1, 0); > + > + return val == ~0UL ? size : ffz(val); > + } > + > + return _find_first_zero_bit(addr, size); > +} > #else /* CONFIG_GENERIC_FIND_FIRST_BIT */ > > #ifndef find_first_bit > @@ -126,6 +147,27 @@ extern unsigned long find_first_zero_bit(const unsigned long *addr, > > #endif /* CONFIG_GENERIC_FIND_FIRST_BIT */ > > +#ifndef find_last_bit > +/** > + * find_last_bit - find the last set bit in a memory region > + * @addr: The address to start the search at > + * @size: The number of bits to search > + * > + * Returns the bit number of the last set bit, or size. > + */ > +static inline > +unsigned long find_last_bit(const unsigned long *addr, unsigned long size) > +{ > + if (small_const_nbits(size)) { > + unsigned long val = *addr & GENMASK(size - 1, 0); > + > + return val ? __fls(val) : size; > + } > + > + return _find_last_bit(addr, size); > +} > +#endif > + > /** > * find_next_clump8 - find next 8-bit clump with set bits in a memory region > * @clump: location to store copy of found clump > diff --git a/include/linux/bitops.h b/include/linux/bitops.h > index a5a48303b0f1..26bf15e6cd35 100644 > --- a/include/linux/bitops.h > +++ b/include/linux/bitops.h > @@ -286,17 +286,5 @@ static __always_inline void __assign_bit(long nr, volatile unsigned long *addr, > }) > #endif > > -#ifndef find_last_bit > -/** > - * find_last_bit - find the last set bit in a memory region > - * @addr: The address to start the search at > - * @size: The number of bits to search > - * > - * Returns the bit number of the last set bit, or size. > - */ > -extern unsigned long find_last_bit(const unsigned long *addr, > - unsigned long size); > -#endif > - > #endif /* __KERNEL__ */ > #endif > diff --git a/lib/find_bit.c b/lib/find_bit.c > index b03a101367f8..0f8e2e369b1d 100644 > --- a/lib/find_bit.c > +++ b/lib/find_bit.c > @@ -75,7 +75,7 @@ EXPORT_SYMBOL(_find_next_bit); > /* > * Find the first set bit in a memory region. > */ > -unsigned long find_first_bit(const unsigned long *addr, unsigned long size) > +unsigned long _find_first_bit(const unsigned long *addr, unsigned long size) > { > unsigned long idx; > > @@ -86,14 +86,14 @@ unsigned long find_first_bit(const unsigned long *addr, unsigned long size) > > return size; > } > -EXPORT_SYMBOL(find_first_bit); > +EXPORT_SYMBOL(_find_first_bit); > #endif > > #ifndef find_first_zero_bit > /* > * Find the first cleared bit in a memory region. > */ > -unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size) > +unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size) > { > unsigned long idx; > > @@ -104,11 +104,11 @@ unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size) > > return size; > } > -EXPORT_SYMBOL(find_first_zero_bit); > +EXPORT_SYMBOL(_find_first_zero_bit); > #endif > > #ifndef find_last_bit > -unsigned long find_last_bit(const unsigned long *addr, unsigned long size) > +unsigned long _find_last_bit(const unsigned long *addr, unsigned long size) > { > if (size) { > unsigned long val = BITMAP_LAST_WORD_MASK(size); > @@ -124,7 +124,7 @@ unsigned long find_last_bit(const unsigned long *addr, unsigned long size) > } > return size; > } > -EXPORT_SYMBOL(find_last_bit); > +EXPORT_SYMBOL(_find_last_bit); > #endif > > unsigned long find_next_clump8(unsigned long *clump, const unsigned long *addr, > -- > 2.25.1 > -- With Best Regards, Andy Shevchenko