From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Easton Subject: Re: [PATCH net-next v3 01/17] asm: simd context helper API Date: Thu, 13 Sep 2018 05:03:01 +0000 Message-ID: <20180913050301.GA26367@ip-172-31-15-78> References: <20180911010838.8818-1-Jason@zx2c4.com> <20180911010838.8818-2-Jason@zx2c4.com> <20180912061433.GA8484@ip-172-31-15-78> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: LKML , Netdev , David Miller , Greg Kroah-Hartman , Andrew Lutomirski , Thomas Gleixner , Samuel Neves , linux-arch@vger.kernel.org To: "Jason A. Donenfeld" Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Wed, Sep 12, 2018 at 08:10:41PM +0200, Jason A. Donenfeld wrote: > On Wed, Sep 12, 2018 at 8:14 AM Kevin Easton wrote: > > Given that it's always supposed to be used like that, mightn't it be > > better if simd_relax() took a pointer to the context, so the call is > > just > > > > simd_relax(&simd_context); > > > > ? > > > > The inlining means that there won't actually be a pointer dereference in > > the emitted code. > > > > If simd_put() also took a pointer then it could set the context back to > > HAVE_NO_SIMD as well? > > That's sort of a neat idea. I guess in this scheme, you'd envision: > > simd_context_t simd_context; > > simd_get(&simd_context); > simd_relax(&simd_context); > simd_put(&simd_context); > > And this way, if simd_context ever becomes a heavier struct, it can be > modified in place rather than returned by value from the function. On > the other hand, it's a little bit more annoying to type and makes it > harder to do declaration and initialization on the same line. 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). - Kevin