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=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 B89B9C33CAF for ; Fri, 17 Jan 2020 01:33:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8DAAF2072E for ; Fri, 17 Jan 2020 01:33:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Ah4TFo6I" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388414AbgAQBdY (ORCPT ); Thu, 16 Jan 2020 20:33:24 -0500 Received: from mail-lf1-f65.google.com ([209.85.167.65]:45155 "EHLO mail-lf1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730070AbgAQBdY (ORCPT ); Thu, 16 Jan 2020 20:33:24 -0500 Received: by mail-lf1-f65.google.com with SMTP id 203so17067914lfa.12; Thu, 16 Jan 2020 17:33:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=Vv41OytkG2lm8SDKlOhg/H6yihO/V8R0f5z4QUp0HiY=; b=Ah4TFo6IAW4T2As4EOtGEwjyCC4a/sieRz+Y9ll6/X1YfVcWC45I32GbSnGbdYDCbA PmwYVbh8mD6sH146gnqDd9pPR1E6Wq/Nq+0qVafy5jYXBBII88hwa9iBwTiZV7vqrRId 1Wrii4CzY7JPvxuGQgCME78phMA22NwqzOojZy+oSzxK2ADHsH9kRkkDpFjXeTZBm5zf WF21SQmP/Gxcg9oxq7ylsx5S8xywWyAqoRb/aloJyaCiP1+z5T1+uaxRxL0c30rjTESI 4OyJorxOeoHIDMq1K0uow3O9+S8DnQ/2PY5qoNGc/ioUXKJ3s4FZHjgaA2QdicF47S1s EFLA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Vv41OytkG2lm8SDKlOhg/H6yihO/V8R0f5z4QUp0HiY=; b=uOi99bAAaazzG0IL3qwUG7I/1PX17QvwtvsAWqV+cFx72PmTaQtrLm14oWTW/+REP3 UJfDDnWfOuJsqJHyDz5BK1SWQ35SolbWhd/d0WYv2P277XlbiJRhoFsT/qAKlssyJL7z ekRoQ7bjprYT8YJXE9PZVGHU2JVnpXzZrW/0oouhhRnMBgNGhN2hS80X6caW0T6b7S0m uRR6zoqujdUkBmDM4GgXmNN+PRHK5+k3CsyVVv46lqhqYsZy9s3CMfIlvXdnxWPsjd6j lPjV0m821Nph+ZapwZfRvk9niqYRxC0kHHHVN28MA0OZcgCZRd1FK4OYTtSTcUx7/zz+ lydw== X-Gm-Message-State: APjAAAU1gzFLg5lnMN1vHF7RTF/zrT/uWNJk+f/edFWv4HwYG24VJ/wm v9xXBAPyuTjS8i3gp+q/oQ4= X-Google-Smtp-Source: APXvYqxw8NkIQQimSy+3i2QsgTXNgXe3GdPb4+CIflp9GmK5A8gUyzNBZXzEBOPS4cO2XeJFaBceUQ== X-Received: by 2002:a19:c1c1:: with SMTP id r184mr4172932lff.128.1579224801780; Thu, 16 Jan 2020 17:33:21 -0800 (PST) Received: from localhost.localdomain ([109.126.145.157]) by smtp.gmail.com with ESMTPSA id q10sm11608696ljj.60.2020.01.16.17.33.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Jan 2020 17:33:21 -0800 (PST) From: Pavel Begunkov To: Alexander Viro , willy@infradead.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] fs: optimise kiocb_set_rw_flags() Date: Fri, 17 Jan 2020 04:32:37 +0300 Message-Id: <5328b35d948ea2a3aa5df2b1d740c7cb1f38c846.1579224594.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: <8cecd243-38aa-292d-15cd-49b485f9253f@gmail.com> References: <8cecd243-38aa-292d-15cd-49b485f9253f@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org kiocb_set_rw_flags() generates a poor code with several memory writes and a lot of jumps. Help compilers to optimise it. Tested with gcc 9.2 on x64-86, and as a result, it its output now is a plain code without jumps accumulating in a register before a memory write. Signed-off-by: Pavel Begunkov --- v2: check for 0 flags in advance (Matthew Wilcox) include/linux/fs.h | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index 98e0349adb52..22b46fc8fdfa 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3402,22 +3402,28 @@ static inline int iocb_flags(struct file *file) static inline int kiocb_set_rw_flags(struct kiocb *ki, rwf_t flags) { + int kiocb_flags = 0; + + if (!flags) + return 0; if (unlikely(flags & ~RWF_SUPPORTED)) return -EOPNOTSUPP; if (flags & RWF_NOWAIT) { if (!(ki->ki_filp->f_mode & FMODE_NOWAIT)) return -EOPNOTSUPP; - ki->ki_flags |= IOCB_NOWAIT; + kiocb_flags |= IOCB_NOWAIT; } if (flags & RWF_HIPRI) - ki->ki_flags |= IOCB_HIPRI; + kiocb_flags |= IOCB_HIPRI; if (flags & RWF_DSYNC) - ki->ki_flags |= IOCB_DSYNC; + kiocb_flags |= IOCB_DSYNC; if (flags & RWF_SYNC) - ki->ki_flags |= (IOCB_DSYNC | IOCB_SYNC); + kiocb_flags |= (IOCB_DSYNC | IOCB_SYNC); if (flags & RWF_APPEND) - ki->ki_flags |= IOCB_APPEND; + kiocb_flags |= IOCB_APPEND; + + ki->ki_flags |= kiocb_flags; return 0; } -- 2.24.0