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=-15.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 5FA08C43460 for ; Tue, 6 Apr 2021 16:03:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3E23F613C4 for ; Tue, 6 Apr 2021 16:03:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232350AbhDFQDm (ORCPT ); Tue, 6 Apr 2021 12:03:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36004 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346130AbhDFQDk (ORCPT ); Tue, 6 Apr 2021 12:03:40 -0400 Received: from mail-oi1-x22d.google.com (mail-oi1-x22d.google.com [IPv6:2607:f8b0:4864:20::22d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8BA24C06174A; Tue, 6 Apr 2021 09:03:30 -0700 (PDT) Received: by mail-oi1-x22d.google.com with SMTP id m13so15605007oiw.13; Tue, 06 Apr 2021 09:03:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=DXuMvybWpRt4PM+Qgqf16jsNWFOgCO9JLNdluWmfwc4=; b=rSCmibMZ1dZuqDCb7K7iRXGaa8DLdSW4UpceS/oPeHg+aAa3Z5dA+LFLCLjP+BjCFr pzg8FZHT4DPAPK5dQ5Hqx7gh6IraXjbGQl/mWrYWcEJhOpuDuNQnkLc8cEVurIJ+7qbc ZDTTh7llH8wy3gRD8aGWRRRHICrI1AnHgo3Di5+K0fiPTayiM9VJzzrrDeikkbgndhoi b9bBgIPbHAYOfmCffNl/DyIday9v8t4AuQ559y4y8zEQEbVM8uK/XLMobgkBuExjzARa XilwGSaxZ4wGJKOwVg60GyAT7QLU9T8/g8beUCVGMhoO9xsC7SaLIIsI9oswNuEFVOvD tWHw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=DXuMvybWpRt4PM+Qgqf16jsNWFOgCO9JLNdluWmfwc4=; b=pFeapIRO+AR1GyIJnjkmLFrttRnz5TNpb8gnY2bBG8cmGMUOWizcG26UiWb/Mnr8Bp UzXvHvHxye7BPy8E4EqtYc8zbDWMHgEyQiQKza7XufVsj+CJzbyo+WKTdI29qKK+mYCC 6tY7VItm+cXaLqdbYN2XEDFFHtIS9iM7ISqAYCJ35S+kVkHeyZnvP3SUBcleN+wzI/R0 mQjZYOFhIWj9wnRCX+7zOk6ZZVBxi9bQ0ADFHaOkOdyEXLgYilL8EkfrI7gP8cFGsNcC v2dzVPpn32Y665AcoCq39iMztxNrKApLwETd6puxxntCLNQFLRteyT6pMshMEJuAyl4M Xo/w== X-Gm-Message-State: AOAM530IONOdKkTEPmnB7pPyO6MiMzqfKawyphLkdss3vmoaT/TKGTw0 W5zd0DC5t69aJIpiBXB0OiU= X-Google-Smtp-Source: ABdhPJwtPQ3FMWZbLH53D6bk91CTQ7Dnfs4MpY6aB20C8cA1Che99rkav8rsszNojUM6Cj43TZKsGw== X-Received: by 2002:aca:1b01:: with SMTP id b1mr3652063oib.177.1617725009996; Tue, 06 Apr 2021 09:03:29 -0700 (PDT) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id f8sm4630528otp.71.2021.04.06.09.03.28 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Tue, 06 Apr 2021 09:03:29 -0700 (PDT) Sender: Guenter Roeck Date: Tue, 6 Apr 2021 09:03:27 -0700 From: Guenter Roeck To: Yury Norov Cc: linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-arch@vger.kernel.org, linux-sh@vger.kernel.org, Alexey Klimov , Andrew Morton , 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 Subject: Re: [PATCH 11/13] lib: add fast path for find_first_*_bit() and find_last_bit() Message-ID: <20210406160327.GA180841@roeck-us.net> References: <20210316015424.1999082-1-yury.norov@gmail.com> <20210316015424.1999082-12-yury.norov@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210316015424.1999082-12-yury.norov@gmail.com> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 15, 2021 at 06:54:22PM -0700, 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. > > Signed-off-by: Yury Norov > --- > 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..8d818b304869 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 & BITS_FIRST(size - 1); > + > + return val ? __ffs(val) : size; This patch results in: include/asm-generic/bitops/find.h: In function 'find_last_bit': include/asm-generic/bitops/find.h:164:16: error: implicit declaration of function '__fls'; did you mean '__ffs'? and: ./include/asm-generic/bitops/__fls.h: At top level: ./include/asm-generic/bitops/__fls.h:13:38: error: conflicting types for '__fls' when building scripts/mod/devicetable-offsets.o. Seen with h8300 builds. Guenter > + } > + > + 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 | ~BITS_FIRST(size - 1); > + > + 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 & BITS_FIRST(size - 1); > + > + 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 2470ae390f3c..e2c301d28568 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 = BITS_FIRST_MASK(size - 1); > @@ -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,