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[209.132.180.67]) by mx.google.com with ESMTP id e22si11402548pgi.66.2019.04.02.12.48.58; Tue, 02 Apr 2019 12:49:14 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@yandex.ru header.s=mail header.b=K4cmJ8+F; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=yandex.ru Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729815AbfDBTLZ (ORCPT + 99 others); Tue, 2 Apr 2019 15:11:25 -0400 Received: from forward501o.mail.yandex.net ([37.140.190.203]:41671 "EHLO forward501o.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726083AbfDBTLZ (ORCPT ); Tue, 2 Apr 2019 15:11:25 -0400 Received: from mxback7o.mail.yandex.net (mxback7o.mail.yandex.net [IPv6:2a02:6b8:0:1a2d::21]) by forward501o.mail.yandex.net (Yandex) with ESMTP id B44261E80271; Tue, 2 Apr 2019 22:11:21 +0300 (MSK) Received: from localhost (localhost [::1]) by mxback7o.mail.yandex.net (nwsmtp/Yandex) with ESMTP id hJLkrDDClS-BJU4Mjb7; Tue, 02 Apr 2019 22:11:21 +0300 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.ru; s=mail; t=1554232281; bh=ujdYPjeV/k1ZxMLKlIqsUF9I3AeNKWX+BJCImrB51nY=; h=Message-Id:Cc:Subject:In-Reply-To:Date:References:To:From; b=K4cmJ8+FtC23oBXGjXYJouLDsm4nEfPnj+IoYBgQuS2+aLqI0UVdVQE9274xtQHPO tJffbZxdbE9Bm+SvFBl78GU2s7fVxFtuglDyhBqc5P+dwmBzBxtZZT8DVKvyCoXOlu rrcLYUL629dwyUGATiaUcAgo5JxMqYs9MGjO+29w= Authentication-Results: mxback7o.mail.yandex.net; dkim=pass header.i=@yandex.ru Received: by sas1-633109cb7707.qloud-c.yandex.net with HTTP; Tue, 02 Apr 2019 22:11:19 +0300 From: Andrey Abramov To: Michael Ellerman Cc: "linuxppc-dev@lists.ozlabs.org" , "linux-kernel@vger.kernel.org" In-Reply-To: <87zhpaox14.fsf@concordia.ellerman.id.au> References: <18626931553963861@sas1-b3ec53dbc12b.qloud-c.yandex.net> <21287961553964090@iva7-8a22bc446c12.qloud-c.yandex.net> <87zhpaox14.fsf@concordia.ellerman.id.au> Subject: Re: [PATCH 2/5] powerpc: module_[32|64].c: replace swap function with built-in one MIME-Version: 1.0 X-Mailer: Yamail [ http://yandex.ru ] 5.0 Date: Tue, 02 Apr 2019 22:11:19 +0300 Message-Id: <673731554232279@sas1-633109cb7707.qloud-c.yandex.net> Content-Transfer-Encoding: 7bit Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 01.04.2019, 13:11, "Michael Ellerman" : > This looks OK. It's a bit of a pity to replace the 8-byte-at-a-time copy > with a byte-at-a-time copy, but I suspect it's insignificant compared to > the overhead of calling the comparison and swap functions. > > And we could always add a generic 8-byte-at-a-time swap function if it's > a bottleneck. I am sorry, I forgot to quickly comment on your letter. Now (after George Spelvin's patches) the generic swap is able to use u64 or u32 if the alignment and size are divisible by 4 or 8, so we lose nothing here.