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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED 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 A9019C07520 for ; Thu, 13 Sep 2018 13:52:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 64EF120854 for ; Thu, 13 Sep 2018 13:52:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="xAgadjPE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 64EF120854 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=zx2c4.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731012AbeIMTCM (ORCPT ); Thu, 13 Sep 2018 15:02:12 -0400 Received: from frisell.zx2c4.com ([192.95.5.64]:44283 "EHLO frisell.zx2c4.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730619AbeIMTCL (ORCPT ); Thu, 13 Sep 2018 15:02:11 -0400 Received: by frisell.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 83f960ba; Thu, 13 Sep 2018 13:35:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=zx2c4.com; h=mime-version :references:in-reply-to:from:date:message-id:subject:to:cc :content-type; s=mail; bh=HVtgmTjepFQpsbnrlNn210uyvC4=; b=xAgadj PEP6dkcRLdtamfJdIG+EB80RZhYGweC1qtxkl0zhMX6mfuheTkGBdAtUZlX/l4jF DBO+XponjWms25gDNOlCDA1HZ1bvt2n6WQggLE2abaGrLLMzAQAtkfMwI9u+27Tm OfiuTjG3ds9IxrLhVbZuOxt7YBP8jsuZEMos3yeH8eI9mM83yMkR0AhHAvinfFxH TpohsiWncx3bgpNbkv7WoGk8gOdr/RimpzclItAzWpaazVIReYY1k3e0CxupS6Ls Rb7m/99huGlMUZ60hrImv3NNo6ifbdGzx0IgqXgGgUTlR2NxFFSQ3ZCLISMyW/4G AMTXTL894omaJDDw== Received: by frisell.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id e75e1bbc (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128:NO); Thu, 13 Sep 2018 13:35:39 +0000 (UTC) Received: by mail-oi0-f44.google.com with SMTP id x197-v6so9473428oix.5; Thu, 13 Sep 2018 06:52:34 -0700 (PDT) X-Gm-Message-State: APzg51D0Xy3aN1b7QgY9zb7tTmXFt8SL8laUuvyxsaTNLnELUSydRkNf +g8b0og3bRO0+B0yXjTbzuGBcdtnL65mP5KtwXY= X-Google-Smtp-Source: ANB0VdYb/Eff09pnZ9EP0hQ9vzDJWKr/rfcFStefrJRVFMjL9LDF4VgZ8Ug9sVbRMGzZwIqaqVmRh6oE0iKeeQfv/8o= X-Received: by 2002:aca:310b:: with SMTP id x11-v6mr6581223oix.74.1536846753360; Thu, 13 Sep 2018 06:52:33 -0700 (PDT) MIME-Version: 1.0 References: <20180911010838.8818-1-Jason@zx2c4.com> <20180911010838.8818-2-Jason@zx2c4.com> <20180912061433.GA8484@ip-172-31-15-78> <20180913050301.GA26367@ip-172-31-15-78> In-Reply-To: <20180913050301.GA26367@ip-172-31-15-78> From: "Jason A. Donenfeld" Date: Thu, 13 Sep 2018 15:52:21 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH net-next v3 01/17] asm: simd context helper API To: kevin@guarana.org, Andrew Lutomirski Cc: LKML , Netdev , David Miller , Greg Kroah-Hartman , Thomas Gleixner , Samuel Neves , linux-arch@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 13, 2018 at 7:03 AM Kevin Easton wrote: > Yes. It's also how most get/put APIs already work in the kernel, eg > kref_get/put (mostly because they tend to be 'getting/putting' an > already-initialized object, though). Right; in this case the object wouldn't be initialized yet, which might defeat the purpose, since one advantage of the & way you mentioned is _put modifies the context. Andy - any opinions on this? The tl;dr is: 1) what we have now: simd_context_t simd_context = simd_get(); for (item in items) { do_something(item); simd_context = simd_relax(simd_context); } simd_put(); 2) what kevin is proposing: simd_context_t simd_context; simd_get(&simd_context); for (item in items) { do_something(item); simd_relax(&simd_context); } simd_put(&simd_context); I can see pros and cons of each approach.