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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 679ACC001DE for ; Fri, 4 Aug 2023 20:05:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=2vq/lLCnwJ6XkD8xc1ccrTqXc9qp2URLFTsdYvJsPRw=; b=k5heuwkslJXEly Lu5rIiN1DIWyTtjqsdkGd2PCoKjTqxKz06tSPIg+kDW/Bdn+VLuyEQ+4/ybhAvJIHecAcwoRNXF9x ElO/2xz/Jqw2emOxUL1iyrwi4GgFRdakYvi5Kgo1pUD7YfNdwITHTVJF2UPTL0vH7FRY+jsqgO7jh 4jySYkSF3SThUffH5CqDY4ujwrWq+VIih35VOsJ1S/pRcPtaK1eTP75TU3T7PGp0fuIFJoAgji6NO 5fYGQPd3hVa6YipKd0aweVTJofKbpqTtRhgv68JX6FGyIGLJ81nR8/tir4Pn2Ntg3CH3SMudseRsy s0Wi9qxFPz4sTUSgnXtg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qS13B-00DATD-0r; Fri, 04 Aug 2023 20:05:29 +0000 Received: from mgamail.intel.com ([192.55.52.115]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qS138-00DASM-36 for linux-arm-kernel@lists.infradead.org; Fri, 04 Aug 2023 20:05:28 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1691179526; x=1722715526; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=61/5zzRVpmjuaeQ+th73cerqMU4YQpzyb5WsNL6XhHg=; b=behz/+Gax4WQEinXL35vTlmKsEMI5cmMK8AyXLI64pptarUBzVHrDDIt Wy1n8G65HvvfR+GDIGGmwm8gaSxVUpMZdktxbgovTu/Q8Ly59bBgp+lD6 x3EGpsccHN/CaZ+9ufOALqK0lsC9ENyYbHoHEZbAauGsWN5mQftjQVKEP 5Lb3Xv97lC64ic8t5wuvFDjJ0k/krtRhKFUuJ2x89R5sA2OgxS1ByqKHz YXKtTwdSmsH0FX4JxsoEP9Utp8/BV/Et1eEuOHgYYiLhr2J0+Jb3ObcCs gTZsApeTaWW6U1M8+JKAcHB7vujAWGLH1wOmL+dkkEhsEHFDxJ49JVVZy Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10792"; a="370225977" X-IronPort-AV: E=Sophos;i="6.01,255,1684825200"; d="scan'208";a="370225977" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Aug 2023 13:05:25 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.01,202,1684825200"; d="scan'208";a="873510290" Received: from smile.fi.intel.com ([10.237.72.54]) by fmsmga001.fm.intel.com with ESMTP; 04 Aug 2023 13:05:24 -0700 Received: from andy by smile.fi.intel.com with local (Exim 4.96) (envelope-from ) id 1qS131-0061z2-3D; Fri, 04 Aug 2023 23:05:19 +0300 Date: Fri, 4 Aug 2023 23:05:19 +0300 From: Andy Shevchenko To: Yury Norov Cc: Alexander Potapenko , catalin.marinas@arm.com, will@kernel.org, pcc@google.com, andreyknvl@gmail.com, linux@rasmusvillemoes.dk, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, eugenis@google.com, syednwaris@gmail.com, william.gray@linaro.org, Arnd Bergmann Subject: Re: [PATCH v4 1/5] lib/bitmap: add bitmap_{set,get}_value() Message-ID: References: <20230720173956.3674987-1-glider@google.com> <20230720173956.3674987-2-glider@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230804_130527_068794_532064B6 X-CRM114-Status: GOOD ( 13.42 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Aug 04, 2023 at 12:55:01PM -0700, Yury Norov wrote: > On Fri, Aug 04, 2023 at 06:07:00PM +0200, Alexander Potapenko wrote: > > > > ~BITMAP_FIRST_WORD_MASK(start)); > > > > > > As I said, ~BITMAP_FIRST_WORD_MASK() is the same as BITMAP_LAST_WORD_MASK() > > > and vise-versa. > > > > Surprisingly, ~BITMAP_FIRST_WORD_MASK() generates better code than > > BITMAP_LAST_WORD_MASK(). > > Wow... If that's consistent across different compilers/arches, we'd > just drop the latter. Thanks for pointing that. I'll check. It might be... ... > > map[index] &= (fit ? (~(GENMASK(nbits - 1, 0) << offset)) : > > ~BITMAP_FIRST_WORD_MASK(start)); ...that both parts of ternary are using negation. So compiler may use negation only once. (Haven't looked at the assembly.) -- With Best Regards, Andy Shevchenko _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel